|  | Index Entry |  | Section | 
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| 
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| # |  |  | 
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|  | #pragma: |  | Pragmas | 
|  | #pragma implementation: |  | C++ Interface | 
|  | #pragma implementation, implied: |  | C++ Interface | 
|  | #pragma interface: |  | C++ Interface | 
| 
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| $ |  |  | 
|---|
|  | $: |  | Dollar Signs | 
| 
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| % |  |  | 
|---|
|  | ‘%’ in constraint: |  | Modifiers | 
|  | %include: |  | Spec Files | 
|  | %include_noerr: |  | Spec Files | 
|  | %rename: |  | Spec Files | 
| 
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| & |  |  | 
|---|
|  | ‘&’ in constraint: |  | Modifiers | 
| 
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| ' |  |  | 
|---|
|  | ': |  | Incompatibilities | 
| 
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| * |  |  | 
|---|
|  | *__builtin_alloca: |  | Other Builtins | 
|  | *__builtin_alloca_with_align: |  | Other Builtins | 
|  | *__builtin_alloca_with_align_and_max: |  | Other Builtins | 
| 
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| + |  |  | 
|---|
|  | ‘+’ in constraint: |  | Modifiers | 
| 
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| - |  |  | 
|---|
|  | -lgcc, use with -nodefaultlibs: |  | Link Options | 
|  | -lgcc, use with -nostdlib: |  | Link Options | 
|  | -march feature modifiers: |  | AArch64 Options | 
|  | -mcpu feature modifiers: |  | AArch64 Options | 
|  | -nodefaultlibs and unresolved references: |  | Link Options | 
|  | -nostdlib and unresolved references: |  | Link Options | 
| 
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| . |  |  | 
|---|
|  | .sdata/.sdata2 references (PowerPC): |  | RS/6000 and PowerPC Options | 
| 
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| / |  |  | 
|---|
|  | //: |  | C++ Comments | 
| 
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| 0 |  |  | 
|---|
|  | ‘0’ in constraint: |  | Simple Constraints | 
| 
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| < |  |  | 
|---|
|  | ‘<’ in constraint: |  | Simple Constraints | 
| 
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| = |  |  | 
|---|
|  | ‘=’ in constraint: |  | Modifiers | 
| 
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| > |  |  | 
|---|
|  | ‘>’ in constraint: |  | Simple Constraints | 
| 
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| ? |  |  | 
|---|
|  | ?:extensions: |  | Conditionals | 
|  | ?:side effect: |  | Conditionals | 
| 
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| _ |  |  | 
|---|
|  | ‘_’ in variables in macros: |  | Typeof | 
|  | _Accumdata type: |  | Fixed-Point | 
|  | _Complexkeyword: |  | Complex | 
|  | _Decimal128data type: |  | Decimal Float | 
|  | _Decimal32data type: |  | Decimal Float | 
|  | _Decimal64data type: |  | Decimal Float | 
|  | _Exit: |  | Other Builtins | 
|  | _exit: |  | Other Builtins | 
|  | _Floatndata types: |  | Floating Types | 
|  | _Floatnxdata types: |  | Floating Types | 
|  | _Fractdata type: |  | Fixed-Point | 
|  | _get_ssp: |  | x86 control-flow protection intrinsics | 
|  | _HTM_FIRST_USER_ABORT_CODE: |  | S/390 System z Built-in Functions | 
|  | _inc_ssp: |  | x86 control-flow protection intrinsics | 
|  | _Satdata type: |  | Fixed-Point | 
|  | _xabort: |  | x86 transactional memory intrinsics | 
|  | _xbegin: |  | x86 transactional memory intrinsics | 
|  | _xend: |  | x86 transactional memory intrinsics | 
|  | _xtest: |  | x86 transactional memory intrinsics | 
|  | __atomic_add_fetch: |  | __atomic Builtins | 
|  | __atomic_always_lock_free: |  | __atomic Builtins | 
|  | __atomic_and_fetch: |  | __atomic Builtins | 
|  | __atomic_clear: |  | __atomic Builtins | 
|  | __atomic_compare_exchange: |  | __atomic Builtins | 
|  | __atomic_compare_exchange_n: |  | __atomic Builtins | 
|  | __atomic_exchange: |  | __atomic Builtins | 
|  | __atomic_exchange_n: |  | __atomic Builtins | 
|  | __atomic_fetch_add: |  | __atomic Builtins | 
|  | __atomic_fetch_and: |  | __atomic Builtins | 
|  | __atomic_fetch_nand: |  | __atomic Builtins | 
|  | __atomic_fetch_or: |  | __atomic Builtins | 
|  | __atomic_fetch_sub: |  | __atomic Builtins | 
|  | __atomic_fetch_xor: |  | __atomic Builtins | 
|  | __atomic_is_lock_free: |  | __atomic Builtins | 
|  | __atomic_load: |  | __atomic Builtins | 
|  | __atomic_load_n: |  | __atomic Builtins | 
|  | __atomic_nand_fetch: |  | __atomic Builtins | 
|  | __atomic_or_fetch: |  | __atomic Builtins | 
|  | __atomic_signal_fence: |  | __atomic Builtins | 
|  | __atomic_store: |  | __atomic Builtins | 
|  | __atomic_store_n: |  | __atomic Builtins | 
|  | __atomic_sub_fetch: |  | __atomic Builtins | 
|  | __atomic_test_and_set: |  | __atomic Builtins | 
|  | __atomic_thread_fence: |  | __atomic Builtins | 
|  | __atomic_xor_fetch: |  | __atomic Builtins | 
|  | __builtin_addf128_round_to_odd: |  | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
|  | __builtin_add_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_add_overflow_p: |  | Integer Overflow Builtins | 
|  | __builtin_alloca: |  | Other Builtins | 
|  | __builtin_alloca_with_align: |  | Other Builtins | 
|  | __builtin_alloca_with_align_and_max: |  | Other Builtins | 
|  | __builtin_apply: |  | Constructing Calls | 
|  | __builtin_apply_args: |  | Constructing Calls | 
|  | __builtin_arc_aligned: |  | ARC Built-in Functions | 
|  | __builtin_arc_brk: |  | ARC Built-in Functions | 
|  | __builtin_arc_core_read: |  | ARC Built-in Functions | 
|  | __builtin_arc_core_write: |  | ARC Built-in Functions | 
|  | __builtin_arc_divaw: |  | ARC Built-in Functions | 
|  | __builtin_arc_flag: |  | ARC Built-in Functions | 
|  | __builtin_arc_lr: |  | ARC Built-in Functions | 
|  | __builtin_arc_mul64: |  | ARC Built-in Functions | 
|  | __builtin_arc_mulu64: |  | ARC Built-in Functions | 
|  | __builtin_arc_nop: |  | ARC Built-in Functions | 
|  | __builtin_arc_norm: |  | ARC Built-in Functions | 
|  | __builtin_arc_normw: |  | ARC Built-in Functions | 
|  | __builtin_arc_rtie: |  | ARC Built-in Functions | 
|  | __builtin_arc_sleep: |  | ARC Built-in Functions | 
|  | __builtin_arc_sr: |  | ARC Built-in Functions | 
|  | __builtin_arc_swap: |  | ARC Built-in Functions | 
|  | __builtin_arc_swi: |  | ARC Built-in Functions | 
|  | __builtin_arc_sync: |  | ARC Built-in Functions | 
|  | __builtin_arc_trap_s: |  | ARC Built-in Functions | 
|  | __builtin_arc_unimp_s: |  | ARC Built-in Functions | 
|  | __builtin_assume_aligned: |  | Other Builtins | 
|  | __builtin_bswap16: |  | Other Builtins | 
|  | __builtin_bswap32: |  | Other Builtins | 
|  | __builtin_bswap64: |  | Other Builtins | 
|  | __builtin_call_with_static_chain: |  | Other Builtins | 
|  | __builtin_call_with_static_chain: |  | Other Builtins | 
|  | __builtin_choose_expr: |  | Other Builtins | 
|  | __builtin_clrsb: |  | Other Builtins | 
|  | __builtin_clrsbl: |  | Other Builtins | 
|  | __builtin_clrsbll: |  | Other Builtins | 
|  | __builtin_clz: |  | Other Builtins | 
|  | __builtin_clzl: |  | Other Builtins | 
|  | __builtin_clzll: |  | Other Builtins | 
|  | __builtin_complex: |  | Other Builtins | 
|  | __builtin_constant_p: |  | Other Builtins | 
|  | __builtin_convertvector: |  | Vector Extensions | 
|  | __builtin_cpu_init: |  | Basic PowerPC Built-in Functions Available on all Configurations | 
|  | __builtin_cpu_init: |  | x86 Built-in Functions | 
|  | __builtin_cpu_is: |  | Basic PowerPC Built-in Functions Available on all Configurations | 
|  | __builtin_cpu_is: |  | x86 Built-in Functions | 
|  | __builtin_cpu_supports: |  | Basic PowerPC Built-in Functions Available on all Configurations | 
|  | __builtin_cpu_supports: |  | x86 Built-in Functions | 
|  | __builtin_ctz: |  | Other Builtins | 
|  | __builtin_ctzl: |  | Other Builtins | 
|  | __builtin_ctzll: |  | Other Builtins | 
|  | __builtin_divf128_round_to_odd: |  | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
|  | __builtin_expect: |  | Other Builtins | 
|  | __builtin_expect_with_probability: |  | Other Builtins | 
|  | __builtin_extend_pointer: |  | Other Builtins | 
|  | __builtin_extend_pointer: |  | Other Builtins | 
|  | __builtin_extract_return_addr: |  | Return Address | 
|  | __builtin_ffs: |  | Other Builtins | 
|  | __builtin_ffsl: |  | Other Builtins | 
|  | __builtin_ffsll: |  | Other Builtins | 
|  | __builtin_FILE: |  | Other Builtins | 
|  | __builtin_fmaf128_round_to_odd: |  | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
|  | __builtin_fpclassify: |  | Other Builtins | 
|  | __builtin_fpclassify: |  | Other Builtins | 
|  | __builtin_frame_address: |  | Return Address | 
|  | __builtin_frob_return_address: |  | Return Address | 
|  | __builtin_FUNCTION: |  | Other Builtins | 
|  | __builtin_goacc_parlevel_id: |  | Other Builtins | 
|  | __builtin_goacc_parlevel_size: |  | Other Builtins | 
|  | __builtin_has_attribute: |  | Other Builtins | 
|  | __builtin_has_attribute: |  | Other Builtins | 
|  | __builtin_huge_val: |  | Other Builtins | 
|  | __builtin_huge_valf: |  | Other Builtins | 
|  | __builtin_huge_valfn: |  | Other Builtins | 
|  | __builtin_huge_valfnx: |  | Other Builtins | 
|  | __builtin_huge_vall: |  | Other Builtins | 
|  | __builtin_huge_valq: |  | x86 Built-in Functions | 
|  | __builtin_inf: |  | Other Builtins | 
|  | __builtin_infd128: |  | Other Builtins | 
|  | __builtin_infd32: |  | Other Builtins | 
|  | __builtin_infd64: |  | Other Builtins | 
|  | __builtin_inff: |  | Other Builtins | 
|  | __builtin_inffn: |  | Other Builtins | 
|  | __builtin_inffnx: |  | Other Builtins | 
|  | __builtin_infl: |  | Other Builtins | 
|  | __builtin_infq: |  | x86 Built-in Functions | 
|  | __builtin_isfinite: |  | Other Builtins | 
|  | __builtin_isgreater: |  | Other Builtins | 
|  | __builtin_isgreaterequal: |  | Other Builtins | 
|  | __builtin_isinf_sign: |  | Other Builtins | 
|  | __builtin_isinf_sign: |  | Other Builtins | 
|  | __builtin_isless: |  | Other Builtins | 
|  | __builtin_islessequal: |  | Other Builtins | 
|  | __builtin_islessgreater: |  | Other Builtins | 
|  | __builtin_isnormal: |  | Other Builtins | 
|  | __builtin_isunordered: |  | Other Builtins | 
|  | __builtin_is_constant_evaluated: |  | Other Builtins | 
|  | __builtin_LINE: |  | Other Builtins | 
|  | __builtin_longjmp: |  | Nonlocal Gotos | 
|  | __builtin_mulf128_round_to_odd: |  | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
|  | __builtin_mul_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_mul_overflow_p: |  | Integer Overflow Builtins | 
|  | __builtin_nan: |  | Other Builtins | 
|  | __builtin_nand128: |  | Other Builtins | 
|  | __builtin_nand32: |  | Other Builtins | 
|  | __builtin_nand64: |  | Other Builtins | 
|  | __builtin_nanf: |  | Other Builtins | 
|  | __builtin_nanfn: |  | Other Builtins | 
|  | __builtin_nanfnx: |  | Other Builtins | 
|  | __builtin_nanl: |  | Other Builtins | 
|  | __builtin_nanq: |  | x86 Built-in Functions | 
|  | __builtin_nans: |  | Other Builtins | 
|  | __builtin_nansf: |  | Other Builtins | 
|  | __builtin_nansfn: |  | Other Builtins | 
|  | __builtin_nansfnx: |  | Other Builtins | 
|  | __builtin_nansl: |  | Other Builtins | 
|  | __builtin_nansq: |  | x86 Built-in Functions | 
|  | __builtin_nds32_isb: |  | NDS32 Built-in Functions | 
|  | __builtin_nds32_isync: |  | NDS32 Built-in Functions | 
|  | __builtin_nds32_mfsr: |  | NDS32 Built-in Functions | 
|  | __builtin_nds32_mfusr: |  | NDS32 Built-in Functions | 
|  | __builtin_nds32_mtsr: |  | NDS32 Built-in Functions | 
|  | __builtin_nds32_mtusr: |  | NDS32 Built-in Functions | 
|  | __builtin_nds32_setgie_dis: |  | NDS32 Built-in Functions | 
|  | __builtin_nds32_setgie_en: |  | NDS32 Built-in Functions | 
|  | __builtin_non_tx_store: |  | S/390 System z Built-in Functions | 
|  | __builtin_object_size: |  | Object Size Checking | 
|  | __builtin_object_size: |  | Object Size Checking | 
|  | __builtin_object_size: |  | Other Builtins | 
|  | __builtin_object_size: |  | Other Builtins | 
|  | __builtin_offsetof: |  | Offsetof | 
|  | __builtin_parity: |  | Other Builtins | 
|  | __builtin_parityl: |  | Other Builtins | 
|  | __builtin_parityll: |  | Other Builtins | 
|  | __builtin_popcount: |  | Other Builtins | 
|  | __builtin_popcountl: |  | Other Builtins | 
|  | __builtin_popcountll: |  | Other Builtins | 
|  | __builtin_powi: |  | Other Builtins | 
|  | __builtin_powi: |  | Other Builtins | 
|  | __builtin_powif: |  | Other Builtins | 
|  | __builtin_powif: |  | Other Builtins | 
|  | __builtin_powil: |  | Other Builtins | 
|  | __builtin_powil: |  | Other Builtins | 
|  | __builtin_prefetch: |  | Other Builtins | 
|  | __builtin_return: |  | Constructing Calls | 
|  | __builtin_return_address: |  | Return Address | 
|  | __builtin_rx_brk: |  | RX Built-in Functions | 
|  | __builtin_rx_clrpsw: |  | RX Built-in Functions | 
|  | __builtin_rx_int: |  | RX Built-in Functions | 
|  | __builtin_rx_machi: |  | RX Built-in Functions | 
|  | __builtin_rx_maclo: |  | RX Built-in Functions | 
|  | __builtin_rx_mulhi: |  | RX Built-in Functions | 
|  | __builtin_rx_mullo: |  | RX Built-in Functions | 
|  | __builtin_rx_mvfachi: |  | RX Built-in Functions | 
|  | __builtin_rx_mvfacmi: |  | RX Built-in Functions | 
|  | __builtin_rx_mvfc: |  | RX Built-in Functions | 
|  | __builtin_rx_mvtachi: |  | RX Built-in Functions | 
|  | __builtin_rx_mvtaclo: |  | RX Built-in Functions | 
|  | __builtin_rx_mvtc: |  | RX Built-in Functions | 
|  | __builtin_rx_mvtipl: |  | RX Built-in Functions | 
|  | __builtin_rx_racw: |  | RX Built-in Functions | 
|  | __builtin_rx_revw: |  | RX Built-in Functions | 
|  | __builtin_rx_rmpa: |  | RX Built-in Functions | 
|  | __builtin_rx_round: |  | RX Built-in Functions | 
|  | __builtin_rx_sat: |  | RX Built-in Functions | 
|  | __builtin_rx_setpsw: |  | RX Built-in Functions | 
|  | __builtin_rx_wait: |  | RX Built-in Functions | 
|  | __builtin_saddll_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_saddl_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_sadd_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_setjmp: |  | Nonlocal Gotos | 
|  | __builtin_set_thread_pointer: |  | SH Built-in Functions | 
|  | __builtin_shuffle: |  | Vector Extensions | 
|  | __builtin_sh_get_fpscr: |  | SH Built-in Functions | 
|  | __builtin_sh_set_fpscr: |  | SH Built-in Functions | 
|  | __builtin_smulll_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_smull_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_smul_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_speculation_safe_value: |  | Other Builtins | 
|  | __builtin_speculation_safe_value: |  | Other Builtins | 
|  | __builtin_sqrtf128_round_to_odd: |  | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
|  | __builtin_ssubll_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_ssubl_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_ssub_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_subf128_round_to_odd: |  | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
|  | __builtin_sub_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_sub_overflow_p: |  | Integer Overflow Builtins | 
|  | __builtin_tabort: |  | S/390 System z Built-in Functions | 
|  | __builtin_tbegin: |  | S/390 System z Built-in Functions | 
|  | __builtin_tbeginc: |  | S/390 System z Built-in Functions | 
|  | __builtin_tbegin_nofloat: |  | S/390 System z Built-in Functions | 
|  | __builtin_tbegin_retry: |  | S/390 System z Built-in Functions | 
|  | __builtin_tbegin_retry_nofloat: |  | S/390 System z Built-in Functions | 
|  | __builtin_tend: |  | S/390 System z Built-in Functions | 
|  | __builtin_tgmath: |  | Other Builtins | 
|  | __builtin_thread_pointer: |  | SH Built-in Functions | 
|  | __builtin_trap: |  | Other Builtins | 
|  | __builtin_truncf128_round_to_odd: |  | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
|  | __builtin_tx_assist: |  | S/390 System z Built-in Functions | 
|  | __builtin_tx_nesting_depth: |  | S/390 System z Built-in Functions | 
|  | __builtin_types_compatible_p: |  | Other Builtins | 
|  | __builtin_uaddll_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_uaddl_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_uadd_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_umulll_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_umull_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_umul_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_unreachable: |  | Other Builtins | 
|  | __builtin_usubll_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_usubl_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_usub_overflow: |  | Integer Overflow Builtins | 
|  | __builtin_va_arg_pack: |  | Constructing Calls | 
|  | __builtin_va_arg_pack_len: |  | Constructing Calls | 
|  | __builtin___clear_cache: |  | Other Builtins | 
|  | __builtin___fprintf_chk: |  | Object Size Checking | 
|  | __builtin___memcpy_chk: |  | Object Size Checking | 
|  | __builtin___memmove_chk: |  | Object Size Checking | 
|  | __builtin___mempcpy_chk: |  | Object Size Checking | 
|  | __builtin___memset_chk: |  | Object Size Checking | 
|  | __builtin___printf_chk: |  | Object Size Checking | 
|  | __builtin___snprintf_chk: |  | Object Size Checking | 
|  | __builtin___sprintf_chk: |  | Object Size Checking | 
|  | __builtin___stpcpy_chk: |  | Object Size Checking | 
|  | __builtin___strcat_chk: |  | Object Size Checking | 
|  | __builtin___strcpy_chk: |  | Object Size Checking | 
|  | __builtin___strncat_chk: |  | Object Size Checking | 
|  | __builtin___strncpy_chk: |  | Object Size Checking | 
|  | __builtin___vfprintf_chk: |  | Object Size Checking | 
|  | __builtin___vprintf_chk: |  | Object Size Checking | 
|  | __builtin___vsnprintf_chk: |  | Object Size Checking | 
|  | __builtin___vsprintf_chk: |  | Object Size Checking | 
|  | __complex__keyword: |  | Complex | 
|  | __declspec(dllexport): |  | Microsoft Windows Function Attributes | 
|  | __declspec(dllimport): |  | Microsoft Windows Function Attributes | 
|  | __eaSPU Named Address Spaces: |  | Named Address Spaces | 
|  | __extension__: |  | Alternate Keywords | 
|  | __farM32C Named Address Spaces: |  | Named Address Spaces | 
|  | __farRL78 Named Address Spaces: |  | Named Address Spaces | 
|  | __flashAVR Named Address Spaces: |  | Named Address Spaces | 
|  | __flash1AVR Named Address Spaces: |  | Named Address Spaces | 
|  | __flash2AVR Named Address Spaces: |  | Named Address Spaces | 
|  | __flash3AVR Named Address Spaces: |  | Named Address Spaces | 
|  | __flash4AVR Named Address Spaces: |  | Named Address Spaces | 
|  | __flash5AVR Named Address Spaces: |  | Named Address Spaces | 
|  | __float128data type: |  | Floating Types | 
|  | __float80data type: |  | Floating Types | 
|  | __fp16data type: |  | Half-Precision | 
|  | __FUNCTION__identifier: |  | Function Names | 
|  | __func__identifier: |  | Function Names | 
|  | __ibm128data type: |  | Floating Types | 
|  | __imag__keyword: |  | Complex | 
|  | __int128data types: |  | __int128 | 
|  | __memxAVR Named Address Spaces: |  | Named Address Spaces | 
|  | __PRETTY_FUNCTION__identifier: |  | Function Names | 
|  | __real__keyword: |  | Complex | 
|  | __seg_fsx86 named address space: |  | Named Address Spaces | 
|  | __seg_gsx86 named address space: |  | Named Address Spaces | 
|  | __STDC_HOSTED__: |  | Standards | 
|  | __sync_add_and_fetch: |  | __sync Builtins | 
|  | __sync_and_and_fetch: |  | __sync Builtins | 
|  | __sync_bool_compare_and_swap: |  | __sync Builtins | 
|  | __sync_fetch_and_add: |  | __sync Builtins | 
|  | __sync_fetch_and_and: |  | __sync Builtins | 
|  | __sync_fetch_and_nand: |  | __sync Builtins | 
|  | __sync_fetch_and_or: |  | __sync Builtins | 
|  | __sync_fetch_and_sub: |  | __sync Builtins | 
|  | __sync_fetch_and_xor: |  | __sync Builtins | 
|  | __sync_lock_release: |  | __sync Builtins | 
|  | __sync_lock_test_and_set: |  | __sync Builtins | 
|  | __sync_nand_and_fetch: |  | __sync Builtins | 
|  | __sync_or_and_fetch: |  | __sync Builtins | 
|  | __sync_sub_and_fetch: |  | __sync Builtins | 
|  | __sync_synchronize: |  | __sync Builtins | 
|  | __sync_val_compare_and_swap: |  | __sync Builtins | 
|  | __sync_xor_and_fetch: |  | __sync Builtins | 
|  | __thread: |  | Thread-Local | 
| 
 | 
| A |  |  | 
|---|
|  | AArch64 Options: |  | AArch64 Options | 
|  | ABI: |  | Compatibility | 
|  | abi_tagfunction attribute: |  | C++ Attributes | 
|  | abi_tagtype attribute: |  | C++ Attributes | 
|  | abi_tagvariable attribute: |  | C++ Attributes | 
|  | abort: |  | Other Builtins | 
|  | abs: |  | Other Builtins | 
|  | absdatavariable attribute, AVR: |  | AVR Variable Attributes | 
|  | accessing volatiles: |  | Volatiles | 
|  | accessing volatiles: |  | C++ Volatiles | 
|  | acos: |  | Other Builtins | 
|  | acosf: |  | Other Builtins | 
|  | acosh: |  | Other Builtins | 
|  | acoshf: |  | Other Builtins | 
|  | acoshl: |  | Other Builtins | 
|  | acosl: |  | Other Builtins | 
|  | Ada: |  | G++ and GCC | 
|  | Ada: |  | G++ and GCC | 
|  | additional floating types: |  | Floating Types | 
|  | address constraints: |  | Simple Constraints | 
|  | address of a label: |  | Labels as Values | 
|  | addressvariable attribute, AVR: |  | AVR Variable Attributes | 
|  | address_operand: |  | Simple Constraints | 
|  | aliasfunction attribute: |  | Common Function Attributes | 
|  | aliasvariable attribute: |  | Common Variable Attributes | 
|  | alignedfunction attribute: |  | Common Function Attributes | 
|  | alignedtype attribute: |  | Common Type Attributes | 
|  | alignedvariable attribute: |  | Common Variable Attributes | 
|  | alignment: |  | Alignment | 
|  | alloca: |  | Other Builtins | 
|  | allocavs variable-length arrays: |  | Variable Length | 
|  | alloc_alignfunction attribute: |  | Common Function Attributes | 
|  | alloc_sizefunction attribute: |  | Common Function Attributes | 
|  | alloc_sizetype attribute: |  | Common Type Attributes | 
|  | alloc_sizevariable attribute: |  | Common Variable Attributes | 
|  | Allow nesting in an interrupt handler on the Blackfin processor: |  | Blackfin Function Attributes | 
|  | Altera Nios II options: |  | Nios II Options | 
|  | alternate keywords: |  | Alternate Keywords | 
|  | altivectype attribute, PowerPC: |  | PowerPC Type Attributes | 
|  | altivecvariable attribute, PowerPC: |  | PowerPC Variable Attributes | 
|  | always_inlinefunction attribute: |  | Common Function Attributes | 
|  | AMD GCN Options: |  | AMD GCN Options | 
|  | AMD1: |  | Standards | 
|  | amdgpu_hsa_kernelfunction attribute, AMD GCN: |  | AMD GCN Function Attributes | 
|  | ANSI C: |  | Standards | 
|  | ANSI C standard: |  | Standards | 
|  | ANSI C89: |  | Standards | 
|  | ANSI support: |  | C Dialect Options | 
|  | ANSI X3.159-1989: |  | Standards | 
|  | apostrophes: |  | Incompatibilities | 
|  | application binary interface: |  | Compatibility | 
|  | ARC options: |  | ARC Options | 
|  | arch=function attribute, AArch64: |  | AArch64 Function Attributes | 
|  | arch=function attribute, ARM: |  | ARM Function Attributes | 
|  | ARM options: |  | ARM Options | 
|  | ARM [Annotated C++ Reference Manual]: |  | Backwards Compatibility | 
|  | arrays of length zero: |  | Zero Length | 
|  | arrays of variable length: |  | Variable Length | 
|  | arrays, non-lvalue: |  | Subscripting | 
|  | artificialfunction attribute: |  | Common Function Attributes | 
|  | asin: |  | Other Builtins | 
|  | asinf: |  | Other Builtins | 
|  | asinh: |  | Other Builtins | 
|  | asinhf: |  | Other Builtins | 
|  | asinhl: |  | Other Builtins | 
|  | asinl: |  | Other Builtins | 
|  | asmassembler template: |  | Extended Asm | 
|  | asmclobbers: |  | Extended Asm | 
|  | asmconstraints: |  | Constraints | 
|  | asmexpressions: |  | Extended Asm | 
|  | asmflag output operands: |  | Extended Asm | 
|  | asmgoto labels: |  | Extended Asm | 
|  | asm inline: |  | Size of an asm | 
|  | asminput operands: |  | Extended Asm | 
|  | asmkeyword: |  | Using Assembly Language with C | 
|  | asmoutput operands: |  | Extended Asm | 
|  | asmscratch registers: |  | Extended Asm | 
|  | asmvolatile: |  | Extended Asm | 
|  | assembler names for identifiers: |  | Asm Labels | 
|  | assembly code, invalid: |  | Bug Criteria | 
|  | assembly language in C: |  | Using Assembly Language with C | 
|  | assembly language in C, basic: |  | Basic Asm | 
|  | assembly language in C, extended: |  | Extended Asm | 
|  | assume_alignedfunction attribute: |  | Common Function Attributes | 
|  | atan: |  | Other Builtins | 
|  | atan2: |  | Other Builtins | 
|  | atan2f: |  | Other Builtins | 
|  | atan2l: |  | Other Builtins | 
|  | atanf: |  | Other Builtins | 
|  | atanh: |  | Other Builtins | 
|  | atanhf: |  | Other Builtins | 
|  | atanhl: |  | Other Builtins | 
|  | atanl: |  | Other Builtins | 
|  | attribute of types: |  | Type Attributes | 
|  | attribute of variables: |  | Variable Attributes | 
|  | attribute syntax: |  | Attribute Syntax | 
|  | autoincrement/decrement addressing: |  | Simple Constraints | 
|  | automatic inlinefor C++ member fns: |  | Inline | 
|  | auxvariable attribute, ARC: |  | ARC Variable Attributes | 
|  | AVR Options: |  | AVR Options | 
| 
 | 
| B |  |  | 
|---|
|  | Backwards Compatibility: |  | Backwards Compatibility | 
|  | bank_switchfunction attribute, M32C: |  | M32C Function Attributes | 
|  | base class members: |  | Name lookup | 
|  | basedtype attribute, MeP: |  | MeP Type Attributes | 
|  | basedvariable attribute, MeP: |  | MeP Variable Attributes | 
|  | basic asm: |  | Basic Asm | 
|  | bcmp: |  | Other Builtins | 
|  | below100variable attribute, Xstormy16: |  | Xstormy16 Variable Attributes | 
|  | binary compatibility: |  | Compatibility | 
|  | Binary constants using the ‘0b’ prefix: |  | Binary constants | 
|  | Blackfin Options: |  | Blackfin Options | 
|  | bound pointer to member function: |  | Bound member functions | 
|  | branch-protectionfunction attribute, AArch64: |  | AArch64 Function Attributes | 
|  | break handler functions: |  | MicroBlaze Function Attributes | 
|  | break_handlerfunction attribute, MicroBlaze: |  | MicroBlaze Function Attributes | 
|  | brk_interruptfunction attribute, RL78: |  | RL78 Function Attributes | 
|  | bug criteria: |  | Bug Criteria | 
|  | bugs: |  | Bugs | 
|  | bugs, known: |  | Trouble | 
|  | built-in functions: |  | C Dialect Options | 
|  | built-in functions: |  | Other Builtins | 
|  | bzero: |  | Other Builtins | 
| 
 | 
| C |  |  | 
|---|
|  | C compilation options: |  | Invoking GCC | 
|  | C intermediate output, nonexistent: |  | G++ and GCC | 
|  | C language extensions: |  | C Extensions | 
|  | C language, traditional: |  | Preprocessor Options | 
|  | C standard: |  | Standards | 
|  | C standards: |  | Standards | 
|  | c++: |  | Invoking G++ | 
|  | C++: |  | G++ and GCC | 
|  | C++ comments: |  | C++ Comments | 
|  | C++ interface and implementation headers: |  | C++ Interface | 
|  | C++ language extensions: |  | C++ Extensions | 
|  | C++ member fns, automatically inline: |  | Inline | 
|  | C++ misunderstandings: |  | C++ Misunderstandings | 
|  | C++ options, command-line: |  | C++ Dialect Options | 
|  | C++ pragmas, effect on inlining: |  | C++ Interface | 
|  | C++ source file suffixes: |  | Invoking G++ | 
|  | C++ static data, declaring and defining: |  | Static Definitions | 
|  | C-SKY Options: |  | C-SKY Options | 
|  | C11: |  | Standards | 
|  | C17: |  | Standards | 
|  | C1X: |  | Standards | 
|  | C2X: |  | Standards | 
|  | C6X Options: |  | C6X Options | 
|  | C89: |  | Standards | 
|  | C90: |  | Standards | 
|  | C94: |  | Standards | 
|  | C95: |  | Standards | 
|  | C99: |  | Standards | 
|  | C9X: |  | Standards | 
|  | cabs: |  | Other Builtins | 
|  | cabsf: |  | Other Builtins | 
|  | cabsl: |  | Other Builtins | 
|  | cacos: |  | Other Builtins | 
|  | cacosf: |  | Other Builtins | 
|  | cacosh: |  | Other Builtins | 
|  | cacoshf: |  | Other Builtins | 
|  | cacoshl: |  | Other Builtins | 
|  | cacosl: |  | Other Builtins | 
|  | callee_pop_aggregate_returnfunction attribute, x86: |  | x86 Function Attributes | 
|  | calling functions through the function vector on SH2A: |  | SH Function Attributes | 
|  | calloc: |  | Other Builtins | 
|  | carg: |  | Other Builtins | 
|  | cargf: |  | Other Builtins | 
|  | cargl: |  | Other Builtins | 
|  | case labels in initializers: |  | Designated Inits | 
|  | case ranges: |  | Case Ranges | 
|  | casin: |  | Other Builtins | 
|  | casinf: |  | Other Builtins | 
|  | casinh: |  | Other Builtins | 
|  | casinhf: |  | Other Builtins | 
|  | casinhl: |  | Other Builtins | 
|  | casinl: |  | Other Builtins | 
|  | cast to a union: |  | Cast to Union | 
|  | catan: |  | Other Builtins | 
|  | catanf: |  | Other Builtins | 
|  | catanh: |  | Other Builtins | 
|  | catanhf: |  | Other Builtins | 
|  | catanhl: |  | Other Builtins | 
|  | catanl: |  | Other Builtins | 
|  | cbvariable attribute, MeP: |  | MeP Variable Attributes | 
|  | cbrt: |  | Other Builtins | 
|  | cbrtf: |  | Other Builtins | 
|  | cbrtl: |  | Other Builtins | 
|  | ccos: |  | Other Builtins | 
|  | ccosf: |  | Other Builtins | 
|  | ccosh: |  | Other Builtins | 
|  | ccoshf: |  | Other Builtins | 
|  | ccoshl: |  | Other Builtins | 
|  | ccosl: |  | Other Builtins | 
|  | cdeclfunction attribute, x86-32: |  | x86 Function Attributes | 
|  | ceil: |  | Other Builtins | 
|  | ceilf: |  | Other Builtins | 
|  | ceill: |  | Other Builtins | 
|  | cexp: |  | Other Builtins | 
|  | cexpf: |  | Other Builtins | 
|  | cexpl: |  | Other Builtins | 
|  | cf_checkfunction attribute, x86: |  | x86 Function Attributes | 
|  | character set, execution: |  | Preprocessor Options | 
|  | character set, input: |  | Preprocessor Options | 
|  | character set, input normalization: |  | Warning Options | 
|  | character set, wide execution: |  | Preprocessor Options | 
|  | cimag: |  | Other Builtins | 
|  | cimagf: |  | Other Builtins | 
|  | cimagl: |  | Other Builtins | 
|  | cleanupvariable attribute: |  | Common Variable Attributes | 
|  | clog: |  | Other Builtins | 
|  | clog10: |  | Other Builtins | 
|  | clog10f: |  | Other Builtins | 
|  | clog10l: |  | Other Builtins | 
|  | clogf: |  | Other Builtins | 
|  | clogl: |  | Other Builtins | 
|  | cmodel=function attribute, AArch64: |  | AArch64 Function Attributes | 
|  | COBOL: |  | G++ and GCC | 
|  | code generation conventions: |  | Code Gen Options | 
|  | code, mixed with declarations: |  | Mixed Declarations | 
|  | coldfunction attribute: |  | Common Function Attributes | 
|  | coldlabel attribute: |  | Label Attributes | 
|  | command options: |  | Invoking GCC | 
|  | comments, C++ style: |  | C++ Comments | 
|  | commonvariable attribute: |  | Common Variable Attributes | 
|  | comparison of signed and unsigned values, warning: |  | Warning Options | 
|  | compilation statistics: |  | Developer Options | 
|  | compiler bugs, reporting: |  | Bug Reporting | 
|  | compiler compared to C++ preprocessor: |  | G++ and GCC | 
|  | compiler options, C++: |  | C++ Dialect Options | 
|  | compiler options, Objective-C and Objective-C++: |  | Objective-C and Objective-C++ Dialect Options | 
|  | compiler version, specifying: |  | Invoking GCC | 
|  | COMPILER_PATH: |  | Environment Variables | 
|  | complex conjugation: |  | Complex | 
|  | complex numbers: |  | Complex | 
|  | compound literals: |  | Compound Literals | 
|  | computed gotos: |  | Labels as Values | 
|  | conditional expressions, extensions: |  | Conditionals | 
|  | conflicting types: |  | Disappointments | 
|  | conj: |  | Other Builtins | 
|  | conjf: |  | Other Builtins | 
|  | conjl: |  | Other Builtins | 
|  | constapplied to function: |  | Function Attributes | 
|  | constfunction attribute: |  | Common Function Attributes | 
|  | const qualifier: |  | Pointers to Arrays | 
|  | constants in constraints: |  | Simple Constraints | 
|  | constraint modifier characters: |  | Modifiers | 
|  | constraint, matching: |  | Simple Constraints | 
|  | constraints, asm: |  | Constraints | 
|  | constraints, machine specific: |  | Machine Constraints | 
|  | constructing calls: |  | Constructing Calls | 
|  | constructor expressions: |  | Compound Literals | 
|  | constructorfunction attribute: |  | Common Function Attributes | 
|  | contributors: |  | Contributors | 
|  | copyfunction attribute: |  | Common Function Attributes | 
|  | copytype attribute: |  | Common Type Attributes | 
|  | copyvariable attribute: |  | Common Variable Attributes | 
|  | copysign: |  | Other Builtins | 
|  | copysignf: |  | Other Builtins | 
|  | copysignl: |  | Other Builtins | 
|  | core dump: |  | Bug Criteria | 
|  | cos: |  | Other Builtins | 
|  | cosf: |  | Other Builtins | 
|  | cosh: |  | Other Builtins | 
|  | coshf: |  | Other Builtins | 
|  | coshl: |  | Other Builtins | 
|  | cosl: |  | Other Builtins | 
|  | CPATH: |  | Environment Variables | 
|  | CPLUS_INCLUDE_PATH: |  | Environment Variables | 
|  | cpow: |  | Other Builtins | 
|  | cpowf: |  | Other Builtins | 
|  | cpowl: |  | Other Builtins | 
|  | cproj: |  | Other Builtins | 
|  | cprojf: |  | Other Builtins | 
|  | cprojl: |  | Other Builtins | 
|  | cpu=function attribute, AArch64: |  | AArch64 Function Attributes | 
|  | CR16 Options: |  | CR16 Options | 
|  | creal: |  | Other Builtins | 
|  | crealf: |  | Other Builtins | 
|  | creall: |  | Other Builtins | 
|  | CRIS Options: |  | CRIS Options | 
|  | criticalfunction attribute, MSP430: |  | MSP430 Function Attributes | 
|  | cross compiling: |  | Invoking GCC | 
|  | csin: |  | Other Builtins | 
|  | csinf: |  | Other Builtins | 
|  | csinh: |  | Other Builtins | 
|  | csinhf: |  | Other Builtins | 
|  | csinhl: |  | Other Builtins | 
|  | csinl: |  | Other Builtins | 
|  | csqrt: |  | Other Builtins | 
|  | csqrtf: |  | Other Builtins | 
|  | csqrtl: |  | Other Builtins | 
|  | ctan: |  | Other Builtins | 
|  | ctanf: |  | Other Builtins | 
|  | ctanh: |  | Other Builtins | 
|  | ctanhf: |  | Other Builtins | 
|  | ctanhl: |  | Other Builtins | 
|  | ctanl: |  | Other Builtins | 
|  | C_INCLUDE_PATH: |  | Environment Variables | 
| 
 | 
| D |  |  | 
|---|
|  | D: |  | G++ and GCC | 
|  | Darwin options: |  | Darwin Options | 
|  | dcgettext: |  | Other Builtins | 
|  | ddinteger suffix: |  | Decimal Float | 
|  | DDinteger suffix: |  | Decimal Float | 
|  | deallocating variable length arrays: |  | Variable Length | 
|  | debug dump options: |  | Developer Options | 
|  | debugging GCC: |  | Developer Options | 
|  | debugging information options: |  | Debugging Options | 
|  | decimal floating types: |  | Decimal Float | 
|  | declaration scope: |  | Incompatibilities | 
|  | declarations inside expressions: |  | Statement Exprs | 
|  | declarations, mixed with code: |  | Mixed Declarations | 
|  | declaring attributes of functions: |  | Function Attributes | 
|  | declaring static data in C++: |  | Static Definitions | 
|  | defining static data in C++: |  | Static Definitions | 
|  | dependencies for make as output: |  | Environment Variables | 
|  | dependencies for make as output: |  | Environment Variables | 
|  | dependencies, make: |  | Preprocessor Options | 
|  | DEPENDENCIES_OUTPUT: |  | Environment Variables | 
|  | dependent name lookup: |  | Name lookup | 
|  | deprecatedenumerator attribute: |  | Enumerator Attributes | 
|  | deprecatedfunction attribute: |  | Common Function Attributes | 
|  | deprecatedtype attribute: |  | Common Type Attributes | 
|  | deprecatedvariable attribute: |  | Common Variable Attributes | 
|  | designated initializers: |  | Designated Inits | 
|  | designated_inittype attribute: |  | Common Type Attributes | 
|  | designator lists: |  | Designated Inits | 
|  | designators: |  | Designated Inits | 
|  | destructorfunction attribute: |  | Common Function Attributes | 
|  | developer options: |  | Developer Options | 
|  | dfinteger suffix: |  | Decimal Float | 
|  | DFinteger suffix: |  | Decimal Float | 
|  | dgettext: |  | Other Builtins | 
|  | diagnostic messages: |  | Diagnostic Message Formatting Options | 
|  | dialect options: |  | C Dialect Options | 
|  | diff-delete GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | diff-filename GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | diff-hunk GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | diff-insert GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | digits in constraint: |  | Simple Constraints | 
|  | directory options: |  | Directory Options | 
|  | disinterruptfunction attribute, Epiphany: |  | Epiphany Function Attributes | 
|  | disinterruptfunction attribute, MeP: |  | MeP Function Attributes | 
|  | dlinteger suffix: |  | Decimal Float | 
|  | DLinteger suffix: |  | Decimal Float | 
|  | dllexportfunction attribute: |  | Microsoft Windows Function Attributes | 
|  | dllexportvariable attribute: |  | Microsoft Windows Variable Attributes | 
|  | dllimportfunction attribute: |  | Microsoft Windows Function Attributes | 
|  | dllimportvariable attribute: |  | Microsoft Windows Variable Attributes | 
|  | dollar signs in identifier names: |  | Dollar Signs | 
|  | double-word arithmetic: |  | Long Long | 
|  | downward funargs: |  | Nested Functions | 
|  | drem: |  | Other Builtins | 
|  | dremf: |  | Other Builtins | 
|  | dreml: |  | Other Builtins | 
|  | dump options: |  | Developer Options | 
| 
 | 
| E |  |  | 
|---|
|  | ‘E’ in constraint: |  | Simple Constraints | 
|  | earlyclobber operand: |  | Modifiers | 
|  | eight-bit data on the H8/300, H8/300H, and H8S: |  | H8/300 Variable Attributes | 
|  | eightbit_datavariable attribute, H8/300: |  | H8/300 Variable Attributes | 
|  | EIND: |  | AVR Options | 
|  | eitherfunction attribute, MSP430: |  | MSP430 Function Attributes | 
|  | eithervariable attribute, MSP430: |  | MSP430 Variable Attributes | 
|  | empty structures: |  | Empty Structures | 
|  | Enumerator Attributes: |  | Enumerator Attributes | 
|  | environment variables: |  | Environment Variables | 
|  | erf: |  | Other Builtins | 
|  | erfc: |  | Other Builtins | 
|  | erfcf: |  | Other Builtins | 
|  | erfcl: |  | Other Builtins | 
|  | erff: |  | Other Builtins | 
|  | erfl: |  | Other Builtins | 
|  | errorfunction attribute: |  | Common Function Attributes | 
|  | error GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | error messages: |  | Warnings and Errors | 
|  | escaped newlines: |  | Escaped Newlines | 
|  | exceptionfunction attribute: |  | NDS32 Function Attributes | 
|  | exception handler functions, Blackfin: |  | Blackfin Function Attributes | 
|  | exception handler functions, NDS32: |  | NDS32 Function Attributes | 
|  | exception_handlerfunction attribute: |  | Blackfin Function Attributes | 
|  | exit: |  | Other Builtins | 
|  | exp: |  | Other Builtins | 
|  | exp10: |  | Other Builtins | 
|  | exp10f: |  | Other Builtins | 
|  | exp10l: |  | Other Builtins | 
|  | exp2: |  | Other Builtins | 
|  | exp2f: |  | Other Builtins | 
|  | exp2l: |  | Other Builtins | 
|  | expf: |  | Other Builtins | 
|  | expl: |  | Other Builtins | 
|  | explicit register variables: |  | Explicit Register Variables | 
|  | expm1: |  | Other Builtins | 
|  | expm1f: |  | Other Builtins | 
|  | expm1l: |  | Other Builtins | 
|  | expressions containing statements: |  | Statement Exprs | 
|  | expressions, constructor: |  | Compound Literals | 
|  | extended asm: |  | Extended Asm | 
|  | extensible constraints: |  | Simple Constraints | 
|  | extensions, ?:: |  | Conditionals | 
|  | extensions, C language: |  | C Extensions | 
|  | extensions, C++ language: |  | C++ Extensions | 
|  | external declaration scope: |  | Incompatibilities | 
|  | externally_visiblefunction attribute: |  | Common Function Attributes | 
|  | extra NOP instructions at the function entry point: |  | Common Function Attributes | 
| 
 | 
| F |  |  | 
|---|
|  | ‘F’ in constraint: |  | Simple Constraints | 
|  | fabs: |  | Other Builtins | 
|  | fabsf: |  | Other Builtins | 
|  | fabsl: |  | Other Builtins | 
|  | fallthroughstatement attribute: |  | Statement Attributes | 
|  | farfunction attribute, MeP: |  | MeP Function Attributes | 
|  | farfunction attribute, MIPS: |  | MIPS Function Attributes | 
|  | fartype attribute, MeP: |  | MeP Type Attributes | 
|  | farvariable attribute, MeP: |  | MeP Variable Attributes | 
|  | fastcallfunction attribute, x86-32: |  | x86 Function Attributes | 
|  | fast_interruptfunction attribute, M32C: |  | M32C Function Attributes | 
|  | fast_interruptfunction attribute, MicroBlaze: |  | MicroBlaze Function Attributes | 
|  | fast_interruptfunction attribute, RX: |  | RX Function Attributes | 
|  | fatal signal: |  | Bug Criteria | 
|  | fdim: |  | Other Builtins | 
|  | fdimf: |  | Other Builtins | 
|  | fdiml: |  | Other Builtins | 
|  | FDL, GNU Free Documentation License: |  | GNU Free Documentation License | 
|  | fentry_namefunction attribute, x86: |  | x86 Function Attributes | 
|  | fentry_sectionfunction attribute, x86: |  | x86 Function Attributes | 
|  | ffs: |  | Other Builtins | 
|  | file name suffix: |  | Overall Options | 
|  | file names: |  | Link Options | 
|  | fix-cortex-a53-835769function attribute, AArch64: |  | AArch64 Function Attributes | 
|  | fixed-point types: |  | Fixed-Point | 
|  | fixit-delete GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | fixit-insert GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | flattenfunction attribute: |  | Common Function Attributes | 
|  | flexible array members: |  | Zero Length | 
|  | floatas function value type: |  | Incompatibilities | 
|  | floating point precision: |  | Disappointments | 
|  | floating-point precision: |  | Optimize Options | 
|  | floor: |  | Other Builtins | 
|  | floorf: |  | Other Builtins | 
|  | floorl: |  | Other Builtins | 
|  | fma: |  | Other Builtins | 
|  | fmaf: |  | Other Builtins | 
|  | fmal: |  | Other Builtins | 
|  | fmax: |  | Other Builtins | 
|  | fmaxf: |  | Other Builtins | 
|  | fmaxl: |  | Other Builtins | 
|  | fmin: |  | Other Builtins | 
|  | fminf: |  | Other Builtins | 
|  | fminl: |  | Other Builtins | 
|  | fmod: |  | Other Builtins | 
|  | fmodf: |  | Other Builtins | 
|  | fmodl: |  | Other Builtins | 
|  | force_align_arg_pointerfunction attribute, x86: |  | x86 Function Attributes | 
|  | formatfunction attribute: |  | Common Function Attributes | 
|  | format_argfunction attribute: |  | Common Function Attributes | 
|  | Fortran: |  | G++ and GCC | 
|  | forwarder_sectionfunction attribute, Epiphany: |  | Epiphany Function Attributes | 
|  | forwarding calls: |  | Constructing Calls | 
|  | fprintf: |  | Other Builtins | 
|  | fprintf_unlocked: |  | Other Builtins | 
|  | fputs: |  | Other Builtins | 
|  | fputs_unlocked: |  | Other Builtins | 
|  | FR30 Options: |  | FR30 Options | 
|  | freestanding environment: |  | Standards | 
|  | freestanding implementation: |  | Standards | 
|  | frexp: |  | Other Builtins | 
|  | frexpf: |  | Other Builtins | 
|  | frexpl: |  | Other Builtins | 
|  | FRV Options: |  | FRV Options | 
|  | fscanf: |  | Other Builtins | 
|  | fscanf, and constant strings: |  | Incompatibilities | 
|  | FT32 Options: |  | FT32 Options | 
|  | function addressability on the M32R/D: |  | M32R/D Function Attributes | 
|  | function attributes: |  | Function Attributes | 
|  | function pointers, arithmetic: |  | Pointer Arith | 
|  | function prototype declarations: |  | Function Prototypes | 
|  | function versions: |  | Function Multiversioning | 
|  | function, size of pointer to: |  | Pointer Arith | 
|  | functions in arbitrary sections: |  | Common Function Attributes | 
|  | functions that are dynamically resolved: |  | Common Function Attributes | 
|  | functions that are passed arguments in registers on x86-32: |  | x86 Function Attributes | 
|  | functions that behave like malloc: |  | Common Function Attributes | 
|  | functions that have no side effects: |  | Common Function Attributes | 
|  | functions that have no side effects: |  | Common Function Attributes | 
|  | functions that never return: |  | Common Function Attributes | 
|  | functions that pop the argument stack on x86-32: |  | x86 Function Attributes | 
|  | functions that pop the argument stack on x86-32: |  | x86 Function Attributes | 
|  | functions that pop the argument stack on x86-32: |  | x86 Function Attributes | 
|  | functions that pop the argument stack on x86-32: |  | x86 Function Attributes | 
|  | functions that return more than once: |  | Common Function Attributes | 
|  | functions with non-null pointer arguments: |  | Common Function Attributes | 
|  | functions with printf,scanf,strftimeorstrfmonstyle arguments: |  | Common Function Attributes | 
|  | function_returnfunction attribute, x86: |  | x86 Function Attributes | 
|  | function_vectorfunction attribute, H8/300: |  | H8/300 Function Attributes | 
|  | function_vectorfunction attribute, M16C/M32C: |  | M32C Function Attributes | 
|  | function_vectorfunction attribute, SH: |  | SH Function Attributes | 
| 
 | 
| G |  |  | 
|---|
|  | ‘G’ in constraint: |  | Simple Constraints | 
|  | ‘g’ in constraint: |  | Simple Constraints | 
|  | g++: |  | Invoking G++ | 
|  | G++: |  | G++ and GCC | 
|  | gamma: |  | Other Builtins | 
|  | gammaf: |  | Other Builtins | 
|  | gammaf_r: |  | Other Builtins | 
|  | gammal: |  | Other Builtins | 
|  | gammal_r: |  | Other Builtins | 
|  | gamma_r: |  | Other Builtins | 
|  | GCC: |  | G++ and GCC | 
|  | GCC command options: |  | Invoking GCC | 
|  | GCC_COLORS environment variable: |  | Diagnostic Message Formatting Options | 
|  | GCC_COMPARE_DEBUG: |  | Environment Variables | 
|  | GCC_EXEC_PREFIX: |  | Environment Variables | 
|  | gcc_structtype attribute, PowerPC: |  | PowerPC Type Attributes | 
|  | gcc_structtype attribute, x86: |  | x86 Type Attributes | 
|  | gcc_structvariable attribute, PowerPC: |  | PowerPC Variable Attributes | 
|  | gcc_structvariable attribute, x86: |  | x86 Variable Attributes | 
|  | gcov: |  | Instrumentation Options | 
|  | general-regs-onlyfunction attribute, AArch64: |  | AArch64 Function Attributes | 
|  | general-regs-onlyfunction attribute, ARM: |  | ARM Function Attributes | 
|  | gettext: |  | Other Builtins | 
|  | global offset table: |  | Code Gen Options | 
|  | global register after longjmp: |  | Global Register Variables | 
|  | global register variables: |  | Global Register Variables | 
|  | GNAT: |  | G++ and GCC | 
|  | GNU C Compiler: |  | G++ and GCC | 
|  | GNU Compiler Collection: |  | G++ and GCC | 
|  | gnu_inlinefunction attribute: |  | Common Function Attributes | 
|  | Go: |  | G++ and GCC | 
|  | goto with computed label: |  | Labels as Values | 
|  | gprof: |  | Instrumentation Options | 
|  | grouping options: |  | Invoking GCC | 
| 
 | 
| H |  |  | 
|---|
|  | ‘H’ in constraint: |  | Simple Constraints | 
|  | half-precision floating point: |  | Half-Precision | 
|  | hardware models and configurations, specifying: |  | Submodel Options | 
|  | hex floats: |  | Hex Floats | 
|  | highlight, color: |  | Diagnostic Message Formatting Options | 
|  | hkfixed-suffix: |  | Fixed-Point | 
|  | HKfixed-suffix: |  | Fixed-Point | 
|  | hosted environment: |  | Standards | 
|  | hosted environment: |  | C Dialect Options | 
|  | hosted environment: |  | C Dialect Options | 
|  | hosted implementation: |  | Standards | 
|  | hotfunction attribute: |  | Common Function Attributes | 
|  | hotlabel attribute: |  | Label Attributes | 
|  | hotpatchfunction attribute, S/390: |  | S/390 Function Attributes | 
|  | HPPA Options: |  | HPPA Options | 
|  | hrfixed-suffix: |  | Fixed-Point | 
|  | HRfixed-suffix: |  | Fixed-Point | 
|  | hypot: |  | Other Builtins | 
|  | hypotf: |  | Other Builtins | 
|  | hypotl: |  | Other Builtins | 
| 
 | 
| I |  |  | 
|---|
|  | ‘i’ in constraint: |  | Simple Constraints | 
|  | ‘I’ in constraint: |  | Simple Constraints | 
|  | IA-64 Options: |  | IA-64 Options | 
|  | IBM RS/6000 and PowerPC Options: |  | RS/6000 and PowerPC Options | 
|  | identifier names, dollar signs in: |  | Dollar Signs | 
|  | identifiers, names in assembler code: |  | Asm Labels | 
|  | ifuncfunction attribute: |  | Common Function Attributes | 
|  | ilogb: |  | Other Builtins | 
|  | ilogbf: |  | Other Builtins | 
|  | ilogbl: |  | Other Builtins | 
|  | imaxabs: |  | Other Builtins | 
|  | implementation-defined behavior, C language: |  | C Implementation | 
|  | implementation-defined behavior, C++ language: |  | C++ Implementation | 
|  | implied #pragma implementation: |  | C++ Interface | 
|  | incompatibilities of GCC: |  | Incompatibilities | 
|  | increment operators: |  | Bug Criteria | 
|  | index: |  | Other Builtins | 
|  | indirect calls, ARC: |  | ARC Function Attributes | 
|  | indirect calls, ARM: |  | ARM Function Attributes | 
|  | indirect calls, Blackfin: |  | Blackfin Function Attributes | 
|  | indirect calls, Epiphany: |  | Epiphany Function Attributes | 
|  | indirect calls, MIPS: |  | MIPS Function Attributes | 
|  | indirect calls, PowerPC: |  | PowerPC Function Attributes | 
|  | indirect functions: |  | Common Function Attributes | 
|  | indirect_branchfunction attribute, x86: |  | x86 Function Attributes | 
|  | indirect_returnfunction attribute, x86: |  | x86 Function Attributes | 
|  | initializations in expressions: |  | Compound Literals | 
|  | initializers with labeled elements: |  | Designated Inits | 
|  | initializers, non-constant: |  | Initializers | 
|  | init_priorityvariable attribute: |  | C++ Attributes | 
|  | inline assembly language: |  | Using Assembly Language with C | 
|  | inlineautomatic for C++ member fns: |  | Inline | 
|  | inline functions: |  | Inline | 
|  | inline functions, omission of: |  | Inline | 
|  | inlining and C++ pragmas: |  | C++ Interface | 
|  | installation trouble: |  | Trouble | 
|  | instrumentation options: |  | Instrumentation Options | 
|  | integrating function code: |  | Inline | 
|  | interface and implementation headers, C++: |  | C++ Interface | 
|  | intermediate C version, nonexistent: |  | G++ and GCC | 
|  | interruptfunction attribute, ARC: |  | ARC Function Attributes | 
|  | interruptfunction attribute, ARM: |  | ARM Function Attributes | 
|  | interruptfunction attribute, AVR: |  | AVR Function Attributes | 
|  | interruptfunction attribute, C-SKY: |  | C-SKY Function Attributes | 
|  | interruptfunction attribute, CR16: |  | CR16 Function Attributes | 
|  | interruptfunction attribute, Epiphany: |  | Epiphany Function Attributes | 
|  | interruptfunction attribute, M32C: |  | M32C Function Attributes | 
|  | interruptfunction attribute, M32R/D: |  | M32R/D Function Attributes | 
|  | interruptfunction attribute, m68k: |  | m68k Function Attributes | 
|  | interruptfunction attribute, MeP: |  | MeP Function Attributes | 
|  | interruptfunction attribute, MIPS: |  | MIPS Function Attributes | 
|  | interruptfunction attribute, MSP430: |  | MSP430 Function Attributes | 
|  | interruptfunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | interruptfunction attribute, RISC-V: |  | RISC-V Function Attributes | 
|  | interruptfunction attribute, RL78: |  | RL78 Function Attributes | 
|  | interruptfunction attribute, RX: |  | RX Function Attributes | 
|  | interruptfunction attribute, V850: |  | V850 Function Attributes | 
|  | interruptfunction attribute, Visium: |  | Visium Function Attributes | 
|  | interruptfunction attribute, x86: |  | x86 Function Attributes | 
|  | interruptfunction attribute, Xstormy16: |  | Xstormy16 Function Attributes | 
|  | interrupt_handlerfunction attribute, Blackfin: |  | Blackfin Function Attributes | 
|  | interrupt_handlerfunction attribute, H8/300: |  | H8/300 Function Attributes | 
|  | interrupt_handlerfunction attribute, m68k: |  | m68k Function Attributes | 
|  | interrupt_handlerfunction attribute, MicroBlaze: |  | MicroBlaze Function Attributes | 
|  | interrupt_handlerfunction attribute, SH: |  | SH Function Attributes | 
|  | interrupt_handlerfunction attribute, V850: |  | V850 Function Attributes | 
|  | interrupt_threadfunction attribute, fido: |  | m68k Function Attributes | 
|  | introduction: |  | Top | 
|  | invalid assembly code: |  | Bug Criteria | 
|  | invalid input: |  | Bug Criteria | 
|  | invoking g++: |  | Invoking G++ | 
|  | iovariable attribute, AVR: |  | AVR Variable Attributes | 
|  | iovariable attribute, MeP: |  | MeP Variable Attributes | 
|  | io_lowvariable attribute, AVR: |  | AVR Variable Attributes | 
|  | isalnum: |  | Other Builtins | 
|  | isalpha: |  | Other Builtins | 
|  | isascii: |  | Other Builtins | 
|  | isblank: |  | Other Builtins | 
|  | iscntrl: |  | Other Builtins | 
|  | isdigit: |  | Other Builtins | 
|  | isgraph: |  | Other Builtins | 
|  | islower: |  | Other Builtins | 
|  | ISO 9899: |  | Standards | 
|  | ISO C: |  | Standards | 
|  | ISO C standard: |  | Standards | 
|  | ISO C11: |  | Standards | 
|  | ISO C17: |  | Standards | 
|  | ISO C1X: |  | Standards | 
|  | ISO C2X: |  | Standards | 
|  | ISO C90: |  | Standards | 
|  | ISO C94: |  | Standards | 
|  | ISO C95: |  | Standards | 
|  | ISO C99: |  | Standards | 
|  | ISO C9X: |  | Standards | 
|  | ISO support: |  | C Dialect Options | 
|  | ISO/IEC 9899: |  | Standards | 
|  | isprint: |  | Other Builtins | 
|  | ispunct: |  | Other Builtins | 
|  | isrfunction attribute, ARM: |  | ARM Function Attributes | 
|  | isrfunction attribute, C-SKY: |  | C-SKY Function Attributes | 
|  | isspace: |  | Other Builtins | 
|  | isupper: |  | Other Builtins | 
|  | iswalnum: |  | Other Builtins | 
|  | iswalpha: |  | Other Builtins | 
|  | iswblank: |  | Other Builtins | 
|  | iswcntrl: |  | Other Builtins | 
|  | iswdigit: |  | Other Builtins | 
|  | iswgraph: |  | Other Builtins | 
|  | iswlower: |  | Other Builtins | 
|  | iswprint: |  | Other Builtins | 
|  | iswpunct: |  | Other Builtins | 
|  | iswspace: |  | Other Builtins | 
|  | iswupper: |  | Other Builtins | 
|  | iswxdigit: |  | Other Builtins | 
|  | isxdigit: |  | Other Builtins | 
| 
 | 
| J |  |  | 
|---|
|  | j0: |  | Other Builtins | 
|  | j0f: |  | Other Builtins | 
|  | j0l: |  | Other Builtins | 
|  | j1: |  | Other Builtins | 
|  | j1f: |  | Other Builtins | 
|  | j1l: |  | Other Builtins | 
|  | jli_alwaysfunction attribute, ARC: |  | ARC Function Attributes | 
|  | jli_fixedfunction attribute, ARC: |  | ARC Function Attributes | 
|  | jn: |  | Other Builtins | 
|  | jnf: |  | Other Builtins | 
|  | jnl: |  | Other Builtins | 
| 
 | 
| K |  |  | 
|---|
|  | kfixed-suffix: |  | Fixed-Point | 
|  | Kfixed-suffix: |  | Fixed-Point | 
|  | keep_interrupts_maskedfunction attribute, MIPS: |  | MIPS Function Attributes | 
|  | kernelattribute, Nvidia PTX: |  | Nvidia PTX Function Attributes | 
|  | keywords, alternate: |  | Alternate Keywords | 
|  | known causes of trouble: |  | Trouble | 
|  | kspisuspfunction attribute, Blackfin: |  | Blackfin Function Attributes | 
| 
 | 
| L |  |  | 
|---|
|  | l1_datavariable attribute, Blackfin: |  | Blackfin Variable Attributes | 
|  | l1_data_Avariable attribute, Blackfin: |  | Blackfin Variable Attributes | 
|  | l1_data_Bvariable attribute, Blackfin: |  | Blackfin Variable Attributes | 
|  | l1_textfunction attribute, Blackfin: |  | Blackfin Function Attributes | 
|  | l2function attribute, Blackfin: |  | Blackfin Function Attributes | 
|  | l2variable attribute, Blackfin: |  | Blackfin Variable Attributes | 
|  | Label Attributes: |  | Label Attributes | 
|  | labeled elements in initializers: |  | Designated Inits | 
|  | labels as values: |  | Labels as Values | 
|  | labs: |  | Other Builtins | 
|  | LANG: |  | Environment Variables | 
|  | LANG: |  | Environment Variables | 
|  | language dialect options: |  | C Dialect Options | 
|  | LC_ALL: |  | Environment Variables | 
|  | LC_CTYPE: |  | Environment Variables | 
|  | LC_MESSAGES: |  | Environment Variables | 
|  | ldexp: |  | Other Builtins | 
|  | ldexpf: |  | Other Builtins | 
|  | ldexpl: |  | Other Builtins | 
|  | leaffunction attribute: |  | Common Function Attributes | 
|  | length-zero arrays: |  | Zero Length | 
|  | lgamma: |  | Other Builtins | 
|  | lgammaf: |  | Other Builtins | 
|  | lgammaf_r: |  | Other Builtins | 
|  | lgammal: |  | Other Builtins | 
|  | lgammal_r: |  | Other Builtins | 
|  | lgamma_r: |  | Other Builtins | 
|  | Libraries: |  | Link Options | 
|  | LIBRARY_PATH: |  | Environment Variables | 
|  | link options: |  | Link Options | 
|  | linker script: |  | Link Options | 
|  | lkfixed-suffix: |  | Fixed-Point | 
|  | LKfixed-suffix: |  | Fixed-Point | 
|  | LLinteger suffix: |  | Long Long | 
|  | llabs: |  | Other Builtins | 
|  | llkfixed-suffix: |  | Fixed-Point | 
|  | LLKfixed-suffix: |  | Fixed-Point | 
|  | llrfixed-suffix: |  | Fixed-Point | 
|  | LLRfixed-suffix: |  | Fixed-Point | 
|  | llrint: |  | Other Builtins | 
|  | llrintf: |  | Other Builtins | 
|  | llrintl: |  | Other Builtins | 
|  | llround: |  | Other Builtins | 
|  | llroundf: |  | Other Builtins | 
|  | llroundl: |  | Other Builtins | 
|  | LM32 options: |  | LM32 Options | 
|  | load address instruction: |  | Simple Constraints | 
|  | local labels: |  | Local Labels | 
|  | local variables in macros: |  | Typeof | 
|  | local variables, specifying registers: |  | Local Register Variables | 
|  | locale: |  | Environment Variables | 
|  | locale definition: |  | Environment Variables | 
|  | locus GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | log: |  | Other Builtins | 
|  | log10: |  | Other Builtins | 
|  | log10f: |  | Other Builtins | 
|  | log10l: |  | Other Builtins | 
|  | log1p: |  | Other Builtins | 
|  | log1pf: |  | Other Builtins | 
|  | log1pl: |  | Other Builtins | 
|  | log2: |  | Other Builtins | 
|  | log2f: |  | Other Builtins | 
|  | log2l: |  | Other Builtins | 
|  | logb: |  | Other Builtins | 
|  | logbf: |  | Other Builtins | 
|  | logbl: |  | Other Builtins | 
|  | logf: |  | Other Builtins | 
|  | logl: |  | Other Builtins | 
|  | long longdata types: |  | Long Long | 
|  | longcallfunction attribute, Blackfin: |  | Blackfin Function Attributes | 
|  | longcallfunction attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | longjmp: |  | Global Register Variables | 
|  | longjmpincompatibilities: |  | Incompatibilities | 
|  | longjmpwarnings: |  | Warning Options | 
|  | long_callfunction attribute, ARC: |  | ARC Function Attributes | 
|  | long_callfunction attribute, ARM: |  | ARM Function Attributes | 
|  | long_callfunction attribute, Epiphany: |  | Epiphany Function Attributes | 
|  | long_callfunction attribute, MIPS: |  | MIPS Function Attributes | 
|  | lowerfunction attribute, MSP430: |  | MSP430 Function Attributes | 
|  | lowervariable attribute, MSP430: |  | MSP430 Variable Attributes | 
|  | lrfixed-suffix: |  | Fixed-Point | 
|  | LRfixed-suffix: |  | Fixed-Point | 
|  | lrint: |  | Other Builtins | 
|  | lrintf: |  | Other Builtins | 
|  | lrintl: |  | Other Builtins | 
|  | lround: |  | Other Builtins | 
|  | lroundf: |  | Other Builtins | 
|  | lroundl: |  | Other Builtins | 
| 
 | 
| M |  |  | 
|---|
|  | ‘m’ in constraint: |  | Simple Constraints | 
|  | M32C options: |  | M32C Options | 
|  | M32R/D options: |  | M32R/D Options | 
|  | M680x0 options: |  | M680x0 Options | 
|  | machine specific constraints: |  | Machine Constraints | 
|  | machine-dependent options: |  | Submodel Options | 
|  | macro with variable arguments: |  | Variadic Macros | 
|  | macros, inline alternative: |  | Inline | 
|  | macros, local labels: |  | Local Labels | 
|  | macros, local variables in: |  | Typeof | 
|  | macros, statements in expressions: |  | Statement Exprs | 
|  | macros, types of arguments: |  | Typeof | 
|  | make: |  | Preprocessor Options | 
|  | malloc: |  | Other Builtins | 
|  | mallocfunction attribute: |  | Common Function Attributes | 
|  | matching constraint: |  | Simple Constraints | 
|  | may_aliastype attribute: |  | Common Type Attributes | 
|  | MCore options: |  | MCore Options | 
|  | medium_callfunction attribute, ARC: |  | ARC Function Attributes | 
|  | member fns, automatically inline: |  | Inline | 
|  | memchr: |  | Other Builtins | 
|  | memcmp: |  | Other Builtins | 
|  | memcpy: |  | Other Builtins | 
|  | memory references in constraints: |  | Simple Constraints | 
|  | mempcpy: |  | Other Builtins | 
|  | memset: |  | Other Builtins | 
|  | MeP options: |  | MeP Options | 
|  | Mercury: |  | G++ and GCC | 
|  | message formatting: |  | Diagnostic Message Formatting Options | 
|  | messages, warning: |  | Warning Options | 
|  | messages, warning and error: |  | Warnings and Errors | 
|  | MicroBlaze Options: |  | MicroBlaze Options | 
|  | micromipsfunction attribute: |  | MIPS Function Attributes | 
|  | middle-operands, omitted: |  | Conditionals | 
|  | MIPS options: |  | MIPS Options | 
|  | mips16function attribute, MIPS: |  | MIPS Function Attributes | 
|  | misunderstandings in C++: |  | C++ Misunderstandings | 
|  | mixed declarations and code: |  | Mixed Declarations | 
|  | mixing assembly language and C: |  | Using Assembly Language with C | 
|  | mktemp, and constant strings: |  | Incompatibilities | 
|  | MMIX Options: |  | MMIX Options | 
|  | MN10300 options: |  | MN10300 Options | 
|  | modetype attribute: |  | Common Type Attributes | 
|  | modevariable attribute: |  | Common Variable Attributes | 
|  | modelfunction attribute, M32R/D: |  | M32R/D Function Attributes | 
|  | modelvariable attribute, IA-64: |  | IA-64 Variable Attributes | 
|  | model-namevariable attribute, M32R/D: |  | M32R/D Variable Attributes | 
|  | modf: |  | Other Builtins | 
|  | modff: |  | Other Builtins | 
|  | modfl: |  | Other Builtins | 
|  | modifiers in constraints: |  | Modifiers | 
|  | Moxie Options: |  | Moxie Options | 
|  | MSP430 Options: |  | MSP430 Options | 
|  | ms_abifunction attribute, x86: |  | x86 Function Attributes | 
|  | ms_hook_prologuefunction attribute, x86: |  | x86 Function Attributes | 
|  | ms_structtype attribute, PowerPC: |  | PowerPC Type Attributes | 
|  | ms_structtype attribute, x86: |  | x86 Type Attributes | 
|  | ms_structvariable attribute, PowerPC: |  | PowerPC Variable Attributes | 
|  | ms_structvariable attribute, x86: |  | x86 Variable Attributes | 
|  | multiple alternative constraints: |  | Multi-Alternative | 
|  | multiprecision arithmetic: |  | Long Long | 
| 
 | 
| N |  |  | 
|---|
|  | ‘n’ in constraint: |  | Simple Constraints | 
|  | nakedfunction attribute, ARM: |  | ARM Function Attributes | 
|  | nakedfunction attribute, AVR: |  | AVR Function Attributes | 
|  | nakedfunction attribute, C-SKY: |  | C-SKY Function Attributes | 
|  | nakedfunction attribute, MCORE: |  | MCORE Function Attributes | 
|  | nakedfunction attribute, MSP430: |  | MSP430 Function Attributes | 
|  | nakedfunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | nakedfunction attribute, RISC-V: |  | RISC-V Function Attributes | 
|  | nakedfunction attribute, RL78: |  | RL78 Function Attributes | 
|  | nakedfunction attribute, RX: |  | RX Function Attributes | 
|  | nakedfunction attribute, SPU: |  | SPU Function Attributes | 
|  | nakedfunction attribute, x86: |  | x86 Function Attributes | 
|  | Named Address Spaces: |  | Named Address Spaces | 
|  | names used in assembler code: |  | Asm Labels | 
|  | naming convention, implementation headers: |  | C++ Interface | 
|  | NDS32 Options: |  | NDS32 Options | 
|  | nearfunction attribute, MeP: |  | MeP Function Attributes | 
|  | nearfunction attribute, MIPS: |  | MIPS Function Attributes | 
|  | neartype attribute, MeP: |  | MeP Type Attributes | 
|  | nearvariable attribute, MeP: |  | MeP Variable Attributes | 
|  | nearbyint: |  | Other Builtins | 
|  | nearbyintf: |  | Other Builtins | 
|  | nearbyintl: |  | Other Builtins | 
|  | nestedfunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | nested functions: |  | Nested Functions | 
|  | nested_readyfunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | nestingfunction attribute, Blackfin: |  | Blackfin Function Attributes | 
|  | newlines (escaped): |  | Escaped Newlines | 
|  | nextafter: |  | Other Builtins | 
|  | nextafterf: |  | Other Builtins | 
|  | nextafterl: |  | Other Builtins | 
|  | nexttoward: |  | Other Builtins | 
|  | nexttowardf: |  | Other Builtins | 
|  | nexttowardl: |  | Other Builtins | 
|  | NFC: |  | Warning Options | 
|  | NFKC: |  | Warning Options | 
|  | Nios II options: |  | Nios II Options | 
|  | nmifunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | NMI handler functions on the Blackfin processor: |  | Blackfin Function Attributes | 
|  | nmi_handlerfunction attribute, Blackfin: |  | Blackfin Function Attributes | 
|  | nocf_checkfunction attribute: |  | x86 Function Attributes | 
|  | noclonefunction attribute: |  | Common Function Attributes | 
|  | nocommonvariable attribute: |  | Common Variable Attributes | 
|  | nocompressionfunction attribute, MIPS: |  | MIPS Function Attributes | 
|  | noinitvariable attribute, MSP430: |  | MSP430 Variable Attributes | 
|  | noinlinefunction attribute: |  | Common Function Attributes | 
|  | noipafunction attribute: |  | Common Function Attributes | 
|  | nomicromipsfunction attribute: |  | MIPS Function Attributes | 
|  | nomips16function attribute, MIPS: |  | MIPS Function Attributes | 
|  | non-constant initializers: |  | Initializers | 
|  | non-static inline function: |  | Inline | 
|  | nonlocal gotos: |  | Nonlocal Gotos | 
|  | nonnullfunction attribute: |  | Common Function Attributes | 
|  | nonstringvariable attribute: |  | Common Variable Attributes | 
|  | nopltfunction attribute: |  | Common Function Attributes | 
|  | noreturnfunction attribute: |  | Common Function Attributes | 
|  | nosave_low_regsfunction attribute, SH: |  | SH Function Attributes | 
|  | note GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | nothrowfunction attribute: |  | Common Function Attributes | 
|  | notsharedtype attribute, ARM: |  | ARM Type Attributes | 
|  | not_nestedfunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | no_caller_saved_registersfunction attribute, x86: |  | x86 Function Attributes | 
|  | no_gccisrfunction attribute, AVR: |  | AVR Function Attributes | 
|  | no_icffunction attribute: |  | Common Function Attributes | 
|  | no_instrument_functionfunction attribute: |  | Common Function Attributes | 
|  | no_profile_instrument_functionfunction attribute: |  | Common Function Attributes | 
|  | no_reorderfunction attribute: |  | Common Function Attributes | 
|  | no_sanitizefunction attribute: |  | Common Function Attributes | 
|  | no_sanitize_addressfunction attribute: |  | Common Function Attributes | 
|  | no_sanitize_threadfunction attribute: |  | Common Function Attributes | 
|  | no_sanitize_undefinedfunction attribute: |  | Common Function Attributes | 
|  | no_split_stackfunction attribute: |  | Common Function Attributes | 
|  | no_stack_limitfunction attribute: |  | Common Function Attributes | 
|  | Nvidia PTX options: |  | Nvidia PTX Options | 
|  | nvptx options: |  | Nvidia PTX Options | 
| 
 | 
| O |  |  | 
|---|
|  | ‘o’ in constraint: |  | Simple Constraints | 
|  | OBJC_INCLUDE_PATH: |  | Environment Variables | 
|  | Objective-C: |  | G++ and GCC | 
|  | Objective-C: |  | Standards | 
|  | Objective-C and Objective-C++ options, command-line: |  | Objective-C and Objective-C++ Dialect Options | 
|  | Objective-C++: |  | G++ and GCC | 
|  | Objective-C++: |  | Standards | 
|  | offsettable address: |  | Simple Constraints | 
|  | old-style function definitions: |  | Function Prototypes | 
|  | omit-leaf-frame-pointerfunction attribute, AArch64: |  | AArch64 Function Attributes | 
|  | omitted middle-operands: |  | Conditionals | 
|  | open coding: |  | Inline | 
|  | OpenACC accelerator programming: |  | C Dialect Options | 
|  | OpenACC accelerator programming: |  | C Dialect Options | 
|  | OpenMP parallel: |  | C Dialect Options | 
|  | OpenMP SIMD: |  | C Dialect Options | 
|  | OpenRISC Options: |  | OpenRISC Options | 
|  | operand constraints, asm: |  | Constraints | 
|  | optimizefunction attribute: |  | Common Function Attributes | 
|  | optimize options: |  | Optimize Options | 
|  | options to control diagnostics formatting: |  | Diagnostic Message Formatting Options | 
|  | options to control warnings: |  | Warning Options | 
|  | options, C++: |  | C++ Dialect Options | 
|  | options, code generation: |  | Code Gen Options | 
|  | options, debugging: |  | Debugging Options | 
|  | options, dialect: |  | C Dialect Options | 
|  | options, directory search: |  | Directory Options | 
|  | options, GCC command: |  | Invoking GCC | 
|  | options, grouping: |  | Invoking GCC | 
|  | options, linking: |  | Link Options | 
|  | options, Objective-C and Objective-C++: |  | Objective-C and Objective-C++ Dialect Options | 
|  | options, optimization: |  | Optimize Options | 
|  | options, order: |  | Invoking GCC | 
|  | options, preprocessor: |  | Preprocessor Options | 
|  | options, profiling: |  | Instrumentation Options | 
|  | options, program instrumentation: |  | Instrumentation Options | 
|  | options, run-time error checking: |  | Instrumentation Options | 
|  | order of evaluation, side effects: |  | Non-bugs | 
|  | order of options: |  | Invoking GCC | 
|  | OS_mainfunction attribute, AVR: |  | AVR Function Attributes | 
|  | OS_taskfunction attribute, AVR: |  | AVR Function Attributes | 
|  | other register constraints: |  | Simple Constraints | 
|  | output file option: |  | Overall Options | 
|  | overloaded virtual function, warning: |  | C++ Dialect Options | 
| 
 | 
| P |  |  | 
|---|
|  | ‘p’ in constraint: |  | Simple Constraints | 
|  | packedtype attribute: |  | Common Type Attributes | 
|  | packedvariable attribute: |  | Common Variable Attributes | 
|  | parameter forward declaration: |  | Variable Length | 
|  | partial_savefunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | patchable_function_entryfunction attribute: |  | Common Function Attributes | 
|  | pcsfunction attribute, ARM: |  | ARM Function Attributes | 
|  | PDP-11 Options: |  | PDP-11 Options | 
|  | persistentvariable attribute, MSP430: |  | MSP430 Variable Attributes | 
|  | PIC: |  | Code Gen Options | 
|  | picoChip options: |  | picoChip Options | 
|  | pmf: |  | Bound member functions | 
|  | pointer arguments: |  | Common Function Attributes | 
|  | pointer arguments in variadic functions: |  | Variadic Pointer Args | 
|  | pointer to member function: |  | Bound member functions | 
|  | pointers to arrays: |  | Pointers to Arrays | 
|  | portions of temporary objects, pointers to: |  | Temporaries | 
|  | pow: |  | Other Builtins | 
|  | pow10: |  | Other Builtins | 
|  | pow10f: |  | Other Builtins | 
|  | pow10l: |  | Other Builtins | 
|  | PowerPC options: |  | PowerPC Options | 
|  | powf: |  | Other Builtins | 
|  | powl: |  | Other Builtins | 
|  | pragma GCC ivdep: |  | Loop-Specific Pragmas | 
|  | pragma GCC optimize: |  | Function Specific Option Pragmas | 
|  | pragma GCC pop_options: |  | Function Specific Option Pragmas | 
|  | pragma GCC push_options: |  | Function Specific Option Pragmas | 
|  | pragma GCC reset_options: |  | Function Specific Option Pragmas | 
|  | pragma GCC target: |  | Function Specific Option Pragmas | 
|  | pragma GCC unroll n: |  | Loop-Specific Pragmas | 
|  | pragma, address: |  | M32C Pragmas | 
|  | pragma, align: |  | Solaris Pragmas | 
|  | pragma, call: |  | MeP Pragmas | 
|  | pragma, coprocessor available: |  | MeP Pragmas | 
|  | pragma, coprocessor call_saved: |  | MeP Pragmas | 
|  | pragma, coprocessor subclass: |  | MeP Pragmas | 
|  | pragma, custom io_volatile: |  | MeP Pragmas | 
|  | pragma, diagnostic: |  | Diagnostic Pragmas | 
|  | pragma, diagnostic: |  | Diagnostic Pragmas | 
|  | pragma, diagnostic: |  | Diagnostic Pragmas | 
|  | pragma, diagnostic: |  | Diagnostic Pragmas | 
|  | pragma, disinterrupt: |  | MeP Pragmas | 
|  | pragma, fini: |  | Solaris Pragmas | 
|  | pragma, init: |  | Solaris Pragmas | 
|  | pragma, longcall: |  | RS/6000 and PowerPC Pragmas | 
|  | pragma, long_calls: |  | ARM Pragmas | 
|  | pragma, long_calls_off: |  | ARM Pragmas | 
|  | pragma, mark: |  | Darwin Pragmas | 
|  | pragma, memregs: |  | M32C Pragmas | 
|  | pragma, no_long_calls: |  | ARM Pragmas | 
|  | pragma, options align: |  | Darwin Pragmas | 
|  | pragma, pop_macro: |  | Push/Pop Macro Pragmas | 
|  | pragma, push_macro: |  | Push/Pop Macro Pragmas | 
|  | pragma, redefine_extname: |  | Symbol-Renaming Pragmas | 
|  | pragma, segment: |  | Darwin Pragmas | 
|  | pragma, unused: |  | Darwin Pragmas | 
|  | pragma, visibility: |  | Visibility Pragmas | 
|  | pragma, weak: |  | Weak Pragmas | 
|  | pragmas: |  | Pragmas | 
|  | pragmas in C++, effect on inlining: |  | C++ Interface | 
|  | pragmas, interface and implementation: |  | C++ Interface | 
|  | pragmas, warning of unknown: |  | Warning Options | 
|  | precompiled headers: |  | Precompiled Headers | 
|  | preprocessing numbers: |  | Incompatibilities | 
|  | preprocessing tokens: |  | Incompatibilities | 
|  | preprocessor options: |  | Preprocessor Options | 
|  | printf: |  | Other Builtins | 
|  | printf_unlocked: |  | Other Builtins | 
|  | prof: |  | Instrumentation Options | 
|  | profiling options: |  | Instrumentation Options | 
|  | progmemvariable attribute, AVR: |  | AVR Variable Attributes | 
|  | program instrumentation options: |  | Instrumentation Options | 
|  | promotion of formal parameters: |  | Function Prototypes | 
|  | purefunction attribute: |  | Common Function Attributes | 
|  | push address instruction: |  | Simple Constraints | 
|  | putchar: |  | Other Builtins | 
|  | puts: |  | Other Builtins | 
| 
 | 
| Q |  |  | 
|---|
|  | qfloating point suffix: |  | Floating Types | 
|  | Qfloating point suffix: |  | Floating Types | 
|  | qsort, and global register variables: |  | Global Register Variables | 
|  | quote GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
| 
 | 
| R |  |  | 
|---|
|  | rfixed-suffix: |  | Fixed-Point | 
|  | Rfixed-suffix: |  | Fixed-Point | 
|  | ‘r’ in constraint: |  | Simple Constraints | 
|  | RAMPD: |  | AVR Options | 
|  | RAMPX: |  | AVR Options | 
|  | RAMPY: |  | AVR Options | 
|  | RAMPZ: |  | AVR Options | 
|  | range1 GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | range2 GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | ranges in case statements: |  | Case Ranges | 
|  | read-only strings: |  | Incompatibilities | 
|  | reentrantfunction attribute, MSP430: |  | MSP430 Function Attributes | 
|  | register variable after longjmp: |  | Global Register Variables | 
|  | registers for local variables: |  | Local Register Variables | 
|  | registers in constraints: |  | Simple Constraints | 
|  | registers, global allocation: |  | Global Register Variables | 
|  | registers, global variables in: |  | Global Register Variables | 
|  | regparmfunction attribute, x86: |  | x86 Function Attributes | 
|  | relocation truncated to fit (ColdFire): |  | M680x0 Options | 
|  | relocation truncated to fit (MIPS): |  | MIPS Options | 
|  | remainder: |  | Other Builtins | 
|  | remainderf: |  | Other Builtins | 
|  | remainderl: |  | Other Builtins | 
|  | remquo: |  | Other Builtins | 
|  | remquof: |  | Other Builtins | 
|  | remquol: |  | Other Builtins | 
|  | renesasfunction attribute, SH: |  | SH Function Attributes | 
|  | reordering, warning: |  | C++ Dialect Options | 
|  | reporting bugs: |  | Bugs | 
|  | resbankfunction attribute, SH: |  | SH Function Attributes | 
|  | resetfunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | reset handler functions: |  | NDS32 Function Attributes | 
|  | rest argument (in macro): |  | Variadic Macros | 
|  | restricted pointers: |  | Restricted Pointers | 
|  | restricted references: |  | Restricted Pointers | 
|  | restricted this pointer: |  | Restricted Pointers | 
|  | returns_nonnullfunction attribute: |  | Common Function Attributes | 
|  | returns_twicefunction attribute: |  | Common Function Attributes | 
|  | rindex: |  | Other Builtins | 
|  | rint: |  | Other Builtins | 
|  | rintf: |  | Other Builtins | 
|  | rintl: |  | Other Builtins | 
|  | RISC-V Options: |  | RISC-V Options | 
|  | RL78 Options: |  | RL78 Options | 
|  | round: |  | Other Builtins | 
|  | roundf: |  | Other Builtins | 
|  | roundl: |  | Other Builtins | 
|  | RS/6000 and PowerPC Options: |  | RS/6000 and PowerPC Options | 
|  | RTTI: |  | Vague Linkage | 
|  | run-time error checking options: |  | Instrumentation Options | 
|  | run-time options: |  | Code Gen Options | 
|  | RX Options: |  | RX Options | 
| 
 | 
| S |  |  | 
|---|
|  | ‘s’ in constraint: |  | Simple Constraints | 
|  | S/390 and zSeries Options: |  | S/390 and zSeries Options | 
|  | saddrvariable attribute, RL78: |  | RL78 Variable Attributes | 
|  | save all registers on the Blackfin: |  | Blackfin Function Attributes | 
|  | save all registers on the H8/300, H8/300H, and H8S: |  | H8/300 Function Attributes | 
|  | saveallfunction attribute, Blackfin: |  | Blackfin Function Attributes | 
|  | saveallfunction attribute, H8/300: |  | H8/300 Function Attributes | 
|  | save_allfunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | save_volatilesfunction attribute, MicroBlaze: |  | MicroBlaze Function Attributes | 
|  | scalar_storage_ordertype attribute: |  | Common Type Attributes | 
|  | scalb: |  | Other Builtins | 
|  | scalbf: |  | Other Builtins | 
|  | scalbl: |  | Other Builtins | 
|  | scalbln: |  | Other Builtins | 
|  | scalblnf: |  | Other Builtins | 
|  | scalblnf: |  | Other Builtins | 
|  | scalbn: |  | Other Builtins | 
|  | scalbnf: |  | Other Builtins | 
|  | scanf, and constant strings: |  | Incompatibilities | 
|  | scanfnl: |  | Other Builtins | 
|  | scope of a variable length array: |  | Variable Length | 
|  | scope of declaration: |  | Disappointments | 
|  | scope of external declarations: |  | Incompatibilities | 
|  | Score Options: |  | Score Options | 
|  | sdavariable attribute, V850: |  | V850 Variable Attributes | 
|  | search path: |  | Directory Options | 
|  | sectionfunction attribute: |  | Common Function Attributes | 
|  | sectionvariable attribute: |  | Common Variable Attributes | 
|  | secure_callfunction attribute, ARC: |  | ARC Function Attributes | 
|  | selectanyvariable attribute: |  | Microsoft Windows Variable Attributes | 
|  | sentinelfunction attribute: |  | Common Function Attributes | 
|  | setjmp: |  | Global Register Variables | 
|  | setjmpincompatibilities: |  | Incompatibilities | 
|  | sharedattribute, Nvidia PTX: |  | Nvidia PTX Variable Attributes | 
|  | shared strings: |  | Incompatibilities | 
|  | sharedvariable attribute: |  | Microsoft Windows Variable Attributes | 
|  | shortcallfunction attribute, Blackfin: |  | Blackfin Function Attributes | 
|  | shortcallfunction attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | short_callfunction attribute, ARC: |  | ARC Function Attributes | 
|  | short_callfunction attribute, ARM: |  | ARM Function Attributes | 
|  | short_callfunction attribute, Epiphany: |  | Epiphany Function Attributes | 
|  | short_callfunction attribute, MIPS: |  | MIPS Function Attributes | 
|  | side effect in ?:: |  | Conditionals | 
|  | side effects, macro argument: |  | Statement Exprs | 
|  | side effects, order of evaluation: |  | Non-bugs | 
|  | sign-return-addressfunction attribute, AArch64: |  | AArch64 Function Attributes | 
|  | signalfunction attribute, AVR: |  | AVR Function Attributes | 
|  | signbit: |  | Other Builtins | 
|  | signbitd128: |  | Other Builtins | 
|  | signbitd32: |  | Other Builtins | 
|  | signbitd64: |  | Other Builtins | 
|  | signbitf: |  | Other Builtins | 
|  | signbitl: |  | Other Builtins | 
|  | signed and unsigned values, comparison warning: |  | Warning Options | 
|  | significand: |  | Other Builtins | 
|  | significandf: |  | Other Builtins | 
|  | significandl: |  | Other Builtins | 
|  | SIMD: |  | C Dialect Options | 
|  | simdfunction attribute: |  | Common Function Attributes | 
|  | simple constraints: |  | Simple Constraints | 
|  | sin: |  | Other Builtins | 
|  | sincos: |  | Other Builtins | 
|  | sincosf: |  | Other Builtins | 
|  | sincosl: |  | Other Builtins | 
|  | sinf: |  | Other Builtins | 
|  | sinh: |  | Other Builtins | 
|  | sinhf: |  | Other Builtins | 
|  | sinhl: |  | Other Builtins | 
|  | sinl: |  | Other Builtins | 
|  | sizeof: |  | Typeof | 
|  | smaller data references: |  | M32R/D Options | 
|  | smaller data references: |  | Nios II Options | 
|  | smaller data references (PowerPC): |  | RS/6000 and PowerPC Options | 
|  | snprintf: |  | Other Builtins | 
|  | Solaris 2 options: |  | Solaris 2 Options | 
|  | SOURCE_DATE_EPOCH: |  | Environment Variables | 
|  | SPARC options: |  | SPARC Options | 
|  | Spec Files: |  | Spec Files | 
|  | specified registers: |  | Explicit Register Variables | 
|  | specifying compiler version and target machine: |  | Invoking GCC | 
|  | specifying hardware config: |  | Submodel Options | 
|  | specifying machine version: |  | Invoking GCC | 
|  | specifying registers for local variables: |  | Local Register Variables | 
|  | speed of compilation: |  | Precompiled Headers | 
|  | sprintf: |  | Other Builtins | 
|  | SPU options: |  | SPU Options | 
|  | spu_vectortype attribute, SPU: |  | SPU Type Attributes | 
|  | spu_vectorvariable attribute, SPU: |  | SPU Variable Attributes | 
|  | sp_switchfunction attribute, SH: |  | SH Function Attributes | 
|  | sqrt: |  | Other Builtins | 
|  | sqrtf: |  | Other Builtins | 
|  | sqrtl: |  | Other Builtins | 
|  | sscanf: |  | Other Builtins | 
|  | sscanf, and constant strings: |  | Incompatibilities | 
|  | sseregparmfunction attribute, x86: |  | x86 Function Attributes | 
|  | stack_protectfunction attribute: |  | Common Function Attributes | 
|  | Statement Attributes: |  | Statement Attributes | 
|  | statements inside expressions: |  | Statement Exprs | 
|  | static data in C++, declaring and defining: |  | Static Definitions | 
|  | stdcallfunction attribute, x86-32: |  | x86 Function Attributes | 
|  | stpcpy: |  | Other Builtins | 
|  | stpncpy: |  | Other Builtins | 
|  | strcasecmp: |  | Other Builtins | 
|  | strcat: |  | Other Builtins | 
|  | strchr: |  | Other Builtins | 
|  | strcmp: |  | Other Builtins | 
|  | strcpy: |  | Other Builtins | 
|  | strcspn: |  | Other Builtins | 
|  | strdup: |  | Other Builtins | 
|  | strfmon: |  | Other Builtins | 
|  | strftime: |  | Other Builtins | 
|  | strict-alignfunction attribute, AArch64: |  | AArch64 Function Attributes | 
|  | string constants: |  | Incompatibilities | 
|  | strlen: |  | Other Builtins | 
|  | strncasecmp: |  | Other Builtins | 
|  | strncat: |  | Other Builtins | 
|  | strncmp: |  | Other Builtins | 
|  | strncpy: |  | Other Builtins | 
|  | strndup: |  | Other Builtins | 
|  | strnlen: |  | Other Builtins | 
|  | strpbrk: |  | Other Builtins | 
|  | strrchr: |  | Other Builtins | 
|  | strspn: |  | Other Builtins | 
|  | strstr: |  | Other Builtins | 
|  | struct: |  | Unnamed Fields | 
|  | struct __htm_tdb: |  | S/390 System z Built-in Functions | 
|  | structures: |  | Incompatibilities | 
|  | structures, constructor expression: |  | Compound Literals | 
|  | submodel options: |  | Submodel Options | 
|  | subscripting: |  | Subscripting | 
|  | subscripting and function values: |  | Subscripting | 
|  | suffixes for C++ source: |  | Invoking G++ | 
|  | SUNPRO_DEPENDENCIES: |  | Environment Variables | 
|  | suppressing warnings: |  | Warning Options | 
|  | surprises in C++: |  | C++ Misunderstandings | 
|  | syntax checking: |  | Warning Options | 
|  | syscall_linkagefunction attribute, IA-64: |  | IA-64 Function Attributes | 
|  | system headers, warnings from: |  | Warning Options | 
|  | sysv_abifunction attribute, x86: |  | x86 Function Attributes | 
| 
 | 
| T |  |  | 
|---|
|  | tan: |  | Other Builtins | 
|  | tanf: |  | Other Builtins | 
|  | tanh: |  | Other Builtins | 
|  | tanhf: |  | Other Builtins | 
|  | tanhl: |  | Other Builtins | 
|  | tanl: |  | Other Builtins | 
|  | targetfunction attribute: |  | Common Function Attributes | 
|  | targetfunction attribute: |  | ARM Function Attributes | 
|  | targetfunction attribute: |  | Nios II Function Attributes | 
|  | targetfunction attribute: |  | PowerPC Function Attributes | 
|  | targetfunction attribute: |  | S/390 Function Attributes | 
|  | targetfunction attribute: |  | x86 Function Attributes | 
|  | target machine, specifying: |  | Invoking GCC | 
|  | target("3dnow")function attribute, x86: |  | x86 Function Attributes | 
|  | target("3dnowa")function attribute, x86: |  | x86 Function Attributes | 
|  | target("abm")function attribute, x86: |  | x86 Function Attributes | 
|  | target("adx")function attribute, x86: |  | x86 Function Attributes | 
|  | target("aes")function attribute, x86: |  | x86 Function Attributes | 
|  | target("align-stringops")function attribute, x86: |  | x86 Function Attributes | 
|  | target("altivec")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("arch=ARCH")function attribute, x86: |  | x86 Function Attributes | 
|  | target("arm")function attribute, ARM: |  | ARM Function Attributes | 
|  | target("avoid-indexed-addresses")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("avx")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx2")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx5124fmaps")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx5124vnniw")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512bitalg")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512bw")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512cd")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512dq")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512er")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512f")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512ifma")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512pf")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512vbmi")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512vbmi2")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512vl")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512vnni")function attribute, x86: |  | x86 Function Attributes | 
|  | target("avx512vpopcntdq")function attribute, x86: |  | x86 Function Attributes | 
|  | target("bmi")function attribute, x86: |  | x86 Function Attributes | 
|  | target("bmi2")function attribute, x86: |  | x86 Function Attributes | 
|  | target("cld")function attribute, x86: |  | x86 Function Attributes | 
|  | target("cldemote")function attribute, x86: |  | x86 Function Attributes | 
|  | target("clflushopt")function attribute, x86: |  | x86 Function Attributes | 
|  | target("clwb")function attribute, x86: |  | x86 Function Attributes | 
|  | target("clzero")function attribute, x86: |  | x86 Function Attributes | 
|  | target("cmpb")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("cpu=CPU")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("crc32")function attribute, x86: |  | x86 Function Attributes | 
|  | target("custom-fpu-cfg=name")function attribute, Nios II: |  | Nios II Function Attributes | 
|  | target("custom-insn=N")function attribute, Nios II: |  | Nios II Function Attributes | 
|  | target("cx16")function attribute, x86: |  | x86 Function Attributes | 
|  | target("default")function attribute, x86: |  | x86 Function Attributes | 
|  | target("dlmzb")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("f16c")function attribute, x86: |  | x86 Function Attributes | 
|  | target("fancy-math-387")function attribute, x86: |  | x86 Function Attributes | 
|  | target("fma")function attribute, x86: |  | x86 Function Attributes | 
|  | target("fma4")function attribute, x86: |  | x86 Function Attributes | 
|  | target("fpmath=FPMATH")function attribute, x86: |  | x86 Function Attributes | 
|  | target("fprnd")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("fpu=")function attribute, ARM: |  | ARM Function Attributes | 
|  | target("friz")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("fsgsbase")function attribute, x86: |  | x86 Function Attributes | 
|  | target("fxsr")function attribute, x86: |  | x86 Function Attributes | 
|  | target("gfni")function attribute, x86: |  | x86 Function Attributes | 
|  | target("hard-dfp")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("hle")function attribute, x86: |  | x86 Function Attributes | 
|  | target("ieee-fp")function attribute, x86: |  | x86 Function Attributes | 
|  | target("inline-all-stringops")function attribute, x86: |  | x86 Function Attributes | 
|  | target("inline-stringops-dynamically")function attribute, x86: |  | x86 Function Attributes | 
|  | target("isel")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("longcall")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("lwp")function attribute, x86: |  | x86 Function Attributes | 
|  | target("lzcnt")function attribute, x86: |  | x86 Function Attributes | 
|  | target("mfcrf")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("mfpgpr")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("mmx")function attribute, x86: |  | x86 Function Attributes | 
|  | target("movbe")function attribute, x86: |  | x86 Function Attributes | 
|  | target("movdir64b")function attribute, x86: |  | x86 Function Attributes | 
|  | target("movdiri")function attribute, x86: |  | x86 Function Attributes | 
|  | target("mulhw")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("multiple")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("mwaitx")function attribute, x86: |  | x86 Function Attributes | 
|  | target("no-custom-insn")function attribute, Nios II: |  | Nios II Function Attributes | 
|  | target("paired")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("pclmul")function attribute, x86: |  | x86 Function Attributes | 
|  | target("pconfig")function attribute, x86: |  | x86 Function Attributes | 
|  | target("pku")function attribute, x86: |  | x86 Function Attributes | 
|  | target("popcnt")function attribute, x86: |  | x86 Function Attributes | 
|  | target("popcntb")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("popcntd")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("powerpc-gfxopt")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("powerpc-gpopt")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("prefetchwt1")function attribute, x86: |  | x86 Function Attributes | 
|  | target("prfchw")function attribute, x86: |  | x86 Function Attributes | 
|  | target("ptwrite")function attribute, x86: |  | x86 Function Attributes | 
|  | target("rdpid")function attribute, x86: |  | x86 Function Attributes | 
|  | target("rdrnd")function attribute, x86: |  | x86 Function Attributes | 
|  | target("rdseed")function attribute, x86: |  | x86 Function Attributes | 
|  | target("recip")function attribute, x86: |  | x86 Function Attributes | 
|  | target("recip-precision")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("rtm")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sahf")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sgx")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sha")function attribute, x86: |  | x86 Function Attributes | 
|  | target("shstk")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sse")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sse2")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sse3")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sse4")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sse4.1")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sse4.2")function attribute, x86: |  | x86 Function Attributes | 
|  | target("sse4a")function attribute, x86: |  | x86 Function Attributes | 
|  | target("ssse3")function attribute, x86: |  | x86 Function Attributes | 
|  | target("string")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("tbm")function attribute, x86: |  | x86 Function Attributes | 
|  | target("thumb")function attribute, ARM: |  | ARM Function Attributes | 
|  | target("tune=TUNE")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("tune=TUNE")function attribute, x86: |  | x86 Function Attributes | 
|  | target("update")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("vaes")function attribute, x86: |  | x86 Function Attributes | 
|  | target("vpclmulqdq")function attribute, x86: |  | x86 Function Attributes | 
|  | target("vsx")function attribute, PowerPC: |  | PowerPC Function Attributes | 
|  | target("waitpkg")function attribute, x86: |  | x86 Function Attributes | 
|  | target("wbnoinvd")function attribute, x86: |  | x86 Function Attributes | 
|  | target("xop")function attribute, x86: |  | x86 Function Attributes | 
|  | target("xsave")function attribute, x86: |  | x86 Function Attributes | 
|  | target("xsavec")function attribute, x86: |  | x86 Function Attributes | 
|  | target("xsaveopt")function attribute, x86: |  | x86 Function Attributes | 
|  | target("xsaves")function attribute, x86: |  | x86 Function Attributes | 
|  | target-dependent options: |  | Submodel Options | 
|  | target_clonesfunction attribute: |  | Common Function Attributes | 
|  | TC1: |  | Standards | 
|  | TC2: |  | Standards | 
|  | TC3: |  | Standards | 
|  | tdavariable attribute, V850: |  | V850 Variable Attributes | 
|  | Technical Corrigenda: |  | Standards | 
|  | Technical Corrigendum 1: |  | Standards | 
|  | Technical Corrigendum 2: |  | Standards | 
|  | Technical Corrigendum 3: |  | Standards | 
|  | template instantiation: |  | Template Instantiation | 
|  | temporaries, lifetime of: |  | Temporaries | 
|  | tentative definitions: |  | Code Gen Options | 
|  | tgamma: |  | Other Builtins | 
|  | tgammaf: |  | Other Builtins | 
|  | tgammal: |  | Other Builtins | 
|  | thiscallfunction attribute, x86-32: |  | x86 Function Attributes | 
|  | Thread-Local Storage: |  | Thread-Local | 
|  | thunks: |  | Nested Functions | 
|  | TILE-Gx options: |  | TILE-Gx Options | 
|  | TILEPro options: |  | TILEPro Options | 
|  | tiny data section on the H8/300H and H8S: |  | H8/300 Variable Attributes | 
|  | tinytype attribute, MeP: |  | MeP Type Attributes | 
|  | tinyvariable attribute, MeP: |  | MeP Variable Attributes | 
|  | tiny_datavariable attribute, H8/300: |  | H8/300 Variable Attributes | 
|  | TLS: |  | Thread-Local | 
|  | tls-dialect=function attribute, AArch64: |  | AArch64 Function Attributes | 
|  | tls_modelvariable attribute: |  | Common Variable Attributes | 
|  | TMPDIR: |  | Environment Variables | 
|  | toascii: |  | Other Builtins | 
|  | tolower: |  | Other Builtins | 
|  | toupper: |  | Other Builtins | 
|  | towlower: |  | Other Builtins | 
|  | towupper: |  | Other Builtins | 
|  | traditional C language: |  | Preprocessor Options | 
|  | transparent_uniontype attribute: |  | Common Type Attributes | 
|  | trapa_handlerfunction attribute, SH: |  | SH Function Attributes | 
|  | trap_exitfunction attribute, SH: |  | SH Function Attributes | 
|  | trunc: |  | Other Builtins | 
|  | truncf: |  | Other Builtins | 
|  | truncl: |  | Other Builtins | 
|  | tune=function attribute, AArch64: |  | AArch64 Function Attributes | 
|  | two-stage name lookup: |  | Name lookup | 
|  | type alignment: |  | Alignment | 
|  | type attributes: |  | Type Attributes | 
|  | type-diff GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | typedef names as function parameters: |  | Incompatibilities | 
|  | typeof: |  | Typeof | 
|  | type_info: |  | Vague Linkage | 
| 
 | 
| U |  |  | 
|---|
|  | uhkfixed-suffix: |  | Fixed-Point | 
|  | UHKfixed-suffix: |  | Fixed-Point | 
|  | uhrfixed-suffix: |  | Fixed-Point | 
|  | UHRfixed-suffix: |  | Fixed-Point | 
|  | ukfixed-suffix: |  | Fixed-Point | 
|  | UKfixed-suffix: |  | Fixed-Point | 
|  | ulkfixed-suffix: |  | Fixed-Point | 
|  | ULKfixed-suffix: |  | Fixed-Point | 
|  | ULLinteger suffix: |  | Long Long | 
|  | ullkfixed-suffix: |  | Fixed-Point | 
|  | ULLKfixed-suffix: |  | Fixed-Point | 
|  | ullrfixed-suffix: |  | Fixed-Point | 
|  | ULLRfixed-suffix: |  | Fixed-Point | 
|  | ulrfixed-suffix: |  | Fixed-Point | 
|  | ULRfixed-suffix: |  | Fixed-Point | 
|  | uncachedtype attribute, ARC: |  | ARC Type Attributes | 
|  | undefined behavior: |  | Bug Criteria | 
|  | undefined function value: |  | Bug Criteria | 
|  | underscores in variables in macros: |  | Typeof | 
|  | union: |  | Unnamed Fields | 
|  | union, casting to a: |  | Cast to Union | 
|  | unions: |  | Incompatibilities | 
|  | unknown pragmas, warning: |  | Warning Options | 
|  | unresolved references and -nodefaultlibs: |  | Link Options | 
|  | unresolved references and -nostdlib: |  | Link Options | 
|  | unusedfunction attribute: |  | Common Function Attributes | 
|  | unusedlabel attribute: |  | Label Attributes | 
|  | unusedtype attribute: |  | Common Type Attributes | 
|  | unusedvariable attribute: |  | Common Variable Attributes | 
|  | upperfunction attribute, MSP430: |  | MSP430 Function Attributes | 
|  | uppervariable attribute, MSP430: |  | MSP430 Variable Attributes | 
|  | urfixed-suffix: |  | Fixed-Point | 
|  | URfixed-suffix: |  | Fixed-Point | 
|  | usedfunction attribute: |  | Common Function Attributes | 
|  | usedvariable attribute: |  | Common Variable Attributes | 
|  | User stack pointer in interrupts on the Blackfin: |  | Blackfin Function Attributes | 
|  | use_debug_exception_returnfunction attribute, MIPS: |  | MIPS Function Attributes | 
|  | use_shadow_register_setfunction attribute, MIPS: |  | MIPS Function Attributes | 
| 
 | 
| V |  |  | 
|---|
|  | ‘V’ in constraint: |  | Simple Constraints | 
|  | V850 Options: |  | V850 Options | 
|  | vague linkage: |  | Vague Linkage | 
|  | value after longjmp: |  | Global Register Variables | 
|  | variable addressability on the M32R/D: |  | M32R/D Variable Attributes | 
|  | variable alignment: |  | Alignment | 
|  | variable attributes: |  | Variable Attributes | 
|  | variable number of arguments: |  | Variadic Macros | 
|  | variable-length array in a structure: |  | Variable Length | 
|  | variable-length array scope: |  | Variable Length | 
|  | variable-length arrays: |  | Variable Length | 
|  | variables in specified registers: |  | Explicit Register Variables | 
|  | variables, local, in macros: |  | Typeof | 
|  | variadic functions, pointer arguments: |  | Variadic Pointer Args | 
|  | variadic macros: |  | Variadic Macros | 
|  | VAX options: |  | VAX Options | 
|  | vectorfunction attribute, RX: |  | RX Function Attributes | 
|  | vector types, using with x86 intrinsics: |  | Vector Extensions | 
|  | vector_sizetype attribute: |  | Common Type Attributes | 
|  | vector_sizevariable attribute: |  | Common Variable Attributes | 
|  | version_idfunction attribute, IA-64: |  | IA-64 Function Attributes | 
|  | vfprintf: |  | Other Builtins | 
|  | vfscanf: |  | Other Builtins | 
|  | visibilityfunction attribute: |  | Common Function Attributes | 
|  | visibilitytype attribute: |  | Common Type Attributes | 
|  | visibilityvariable attribute: |  | Common Variable Attributes | 
|  | Visium options: |  | Visium Options | 
|  | VLAs: |  | Variable Length | 
|  | vliwfunction attribute, MeP: |  | MeP Function Attributes | 
|  | void pointers, arithmetic: |  | Pointer Arith | 
|  | void, size of pointer to: |  | Pointer Arith | 
|  | volatile access: |  | Volatiles | 
|  | volatile access: |  | C++ Volatiles | 
|  | volatileapplied to function: |  | Function Attributes | 
|  | volatile asm: |  | Extended Asm | 
|  | volatile read: |  | Volatiles | 
|  | volatile read: |  | C++ Volatiles | 
|  | volatile write: |  | Volatiles | 
|  | volatile write: |  | C++ Volatiles | 
|  | vprintf: |  | Other Builtins | 
|  | vscanf: |  | Other Builtins | 
|  | vsnprintf: |  | Other Builtins | 
|  | vsprintf: |  | Other Builtins | 
|  | vsscanf: |  | Other Builtins | 
|  | vtable: |  | Vague Linkage | 
|  | VxWorks Options: |  | VxWorks Options | 
| 
 | 
| W |  |  | 
|---|
|  | wfloating point suffix: |  | Floating Types | 
|  | Wfloating point suffix: |  | Floating Types | 
|  | wakeupfunction attribute, MSP430: |  | MSP430 Function Attributes | 
|  | warmfunction attribute, NDS32: |  | NDS32 Function Attributes | 
|  | warning for comparison of signed and unsigned values: |  | Warning Options | 
|  | warning for overloaded virtual function: |  | C++ Dialect Options | 
|  | warning for reordering of member initializers: |  | C++ Dialect Options | 
|  | warning for unknown pragmas: |  | Warning Options | 
|  | warningfunction attribute: |  | Common Function Attributes | 
|  | warning GCC_COLORS capability: |  | Diagnostic Message Formatting Options | 
|  | warning messages: |  | Warning Options | 
|  | warnings from system headers: |  | Warning Options | 
|  | warnings vs errors: |  | Warnings and Errors | 
|  | warn_if_not_alignedtype attribute: |  | Common Type Attributes | 
|  | warn_if_not_alignedvariable attribute: |  | Common Variable Attributes | 
|  | warn_unusedtype attribute: |  | C++ Attributes | 
|  | warn_unused_resultfunction attribute: |  | Common Function Attributes | 
|  | weakfunction attribute: |  | Common Function Attributes | 
|  | weakvariable attribute: |  | Common Variable Attributes | 
|  | weakreffunction attribute: |  | Common Function Attributes | 
|  | whitespace: |  | Incompatibilities | 
|  | Windows Options for x86: |  | x86 Windows Options | 
| 
 | 
| X |  |  | 
|---|
|  | ‘X’ in constraint: |  | Simple Constraints | 
|  | X3.159-1989: |  | Standards | 
|  | x86 named address spaces: |  | Named Address Spaces | 
|  | x86 Options: |  | x86 Options | 
|  | x86 Windows Options: |  | x86 Windows Options | 
|  | Xstormy16 Options: |  | Xstormy16 Options | 
|  | Xtensa Options: |  | Xtensa Options | 
| 
 | 
| Y |  |  | 
|---|
|  | y0: |  | Other Builtins | 
|  | y0f: |  | Other Builtins | 
|  | y0l: |  | Other Builtins | 
|  | y1: |  | Other Builtins | 
|  | y1f: |  | Other Builtins | 
|  | y1l: |  | Other Builtins | 
|  | yn: |  | Other Builtins | 
|  | ynf: |  | Other Builtins | 
|  | ynl: |  | Other Builtins | 
| 
 | 
| Z |  |  | 
|---|
|  | zdavariable attribute, V850: |  | V850 Variable Attributes | 
|  | zero-length arrays: |  | Zero Length | 
|  | zero-size structures: |  | Empty Structures | 
|  | zSeries options: |  | zSeries Options | 
| 
 |