Where Online Learning is simpler!
The C and C++ Include Header Files
cat -n /usr/include/assert.h
1 /* Copyright (C) 1991-2026 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <https://www.gnu.org/licenses/>. */ 17 18 /* 19 * ISO C99 Standard: 7.2 Diagnostics <assert.h> 20 */ 21 22 #ifdef _ASSERT_H 23 24 # undef _ASSERT_H 25 # undef assert 26 # undef __ASSERT_VOID_CAST 27 28 # ifdef __USE_GNU 29 # undef assert_perror 30 # endif 31 32 #endif /* assert.h */ 33 34 #define _ASSERT_H 1 35 #include <features.h> 36 37 #if __GLIBC_USE (ISOC23) 38 # ifndef __STDC_VERSION_ASSERT_H__ 39 # define __STDC_VERSION_ASSERT_H__ 202311L 40 # endif 41 #endif 42 43 #if defined __cplusplus && __GNUC_PREREQ (2,95) 44 # define __ASSERT_VOID_CAST static_cast<void> 45 #else 46 # define __ASSERT_VOID_CAST (void) 47 #endif 48 49 /* C23 makes assert a variadic macro so that expressions with a comma 50 not between parentheses, but that would still be valid as a single 51 function argument, such as those involving compound literals with a 52 comma in the initializer list, can be passed to assert. This 53 depends on support for variadic macros (added in C99 and GCC 2.95), 54 and on support for _Bool (added in C99 and GCC 3.0) in order to 55 validate that only a single expression is passed as an argument, 56 and is currently implemented only for C. */ 57 #if (__GLIBC_USE (ISOC23) \ 58 && (defined __GNUC__ \ 59 ? __GNUC_PREREQ (3, 0) \ 60 : defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L) \ 61 && !defined __cplusplus) 62 # define __ASSERT_VARIADIC 1 63 #else 64 # define __ASSERT_VARIADIC 0 65 #endif 66 67 /* void assert (int expression); 68 69 If NDEBUG is defined, do nothing. 70 If not, and EXPRESSION is zero, print an error message and abort. */ 71 72 #ifdef NDEBUG 73 74 # if __ASSERT_VARIADIC 75 # define assert(...) (__ASSERT_VOID_CAST (0)) 76 # else 77 # define assert(expr) (__ASSERT_VOID_CAST (0)) 78 # endif 79 80 /* void assert_perror (int errnum); 81 82 If NDEBUG is defined, do nothing. If not, and ERRNUM is not zero, print an 83 error message with the error text for ERRNUM and abort. 84 (This is a GNU extension.) */ 85 86 # ifdef __USE_GNU 87 # define assert_perror(errnum) (__ASSERT_VOID_CAST (0)) 88 # endif 89 90 #else /* Not NDEBUG. */ 91 92 #ifndef _ASSERT_H_DECLS 93 #define _ASSERT_H_DECLS 94 __BEGIN_DECLS 95 96 /* This prints an "Assertion failed" message and aborts. */ 97 extern void __assert_fail (const char *__assertion, const char *__file, 98 unsigned int __line, const char *__function) 99 __THROW __attribute__ ((__noreturn__)) __COLD; 100 101 /* Likewise, but prints the error text for ERRNUM. */ 102 extern void __assert_perror_fail (int __errnum, const char *__file, 103 unsigned int __line, const char *__function) 104 __THROW __attribute__ ((__noreturn__)) __COLD; 105 106 107 /* The following is not at all used here but needed for standard 108 compliance. */ 109 extern void __assert (const char *__assertion, const char *__file, int __line) 110 __THROW __attribute__ ((__noreturn__)) __COLD; 111 112 113 # if __ASSERT_VARIADIC 114 /* This function is not defined and is not called outside of an 115 unevaluated sizeof, but serves to verify that the argument to 116 assert is a single expression. */ 117 extern _Bool __assert_single_arg (_Bool); 118 # endif 119 120 __END_DECLS 121 #endif /* Not _ASSERT_H_DECLS */ 122 123 /* When possible, define assert so that it does not add extra 124 parentheses around EXPR. Otherwise, those added parentheses would 125 suppress warnings we'd expect to be detected by gcc's -Wparentheses. */ 126 # if defined __cplusplus 127 # if defined __has_builtin 128 # if __has_builtin (__builtin_FILE) 129 # define __ASSERT_FILE __builtin_FILE () 130 # define __ASSERT_LINE __builtin_LINE () 131 # endif 132 # endif 133 # if !defined __ASSERT_FILE 134 # define __ASSERT_FILE __FILE__ 135 # define __ASSERT_LINE __LINE__ 136 # endif 137 # define assert(expr) \ 138 (static_cast <bool> (expr) \ 139 ? void (0) \ 140 : __assert_fail (#expr, __ASSERT_FILE, __ASSERT_LINE, \ 141 __ASSERT_FUNCTION)) 142 # elif !defined __GNUC__ || defined __STRICT_ANSI__ 143 # if __ASSERT_VARIADIC 144 # define assert(...) \ 145 (((void) sizeof (__assert_single_arg (__VA_ARGS__)), __VA_ARGS__) \ 146 ? __ASSERT_VOID_CAST (0) \ 147 : __assert_fail (#__VA_ARGS__, __FILE__, __LINE__, __ASSERT_FUNCTION)) 148 # else 149 # define assert(expr) \ 150 ((expr) \ 151 ? __ASSERT_VOID_CAST (0) \ 152 : __assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION)) 153 # endif 154 # else 155 # if __ASSERT_VARIADIC 156 # define assert(...) \ 157 ((void) sizeof (__assert_single_arg (__VA_ARGS__)), __extension__ ({ \ 158 if (__VA_ARGS__) \ 159 ; /* empty */ \ 160 else \ 161 __assert_fail (#__VA_ARGS__, __FILE__, __LINE__, __ASSERT_FUNCTION); \ 162 })) 163 # else 164 /* The first occurrence of EXPR is not evaluated due to the sizeof, 165 but will trigger any pedantic warnings masked by the __extension__ 166 for the second occurrence. The ternary operator is required to 167 support function pointers and bit fields in this context, and to 168 suppress the evaluation of variable length arrays. */ 169 # define assert(expr) \ 170 ((void) sizeof ((expr) ? 1 : 0), __extension__ ({ \ 171 if (expr) \ 172 ; /* empty */ \ 173 else \ 174 __assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION); \ 175 })) 176 # endif 177 # endif 178 179 # ifdef __USE_GNU 180 # define assert_perror(errnum) \ 181 (!(errnum) \ 182 ? __ASSERT_VOID_CAST (0) \ 183 : __assert_perror_fail ((errnum), __FILE__, __LINE__, __ASSERT_FUNCTION)) 184 # endif 185 186 /* Version 2.4 and later of GCC define a magical variable `__PRETTY_FUNCTION__' 187 which contains the name of the function currently being defined. 188 This is broken in G++ before version 2.6. 189 C9x has a similar variable called __func__, but prefer the GCC one since 190 it demangles C++ function names. */ 191 # if defined __cplusplus ? __GNUC_PREREQ (2, 6) : __GNUC_PREREQ (2, 4) 192 # define __ASSERT_FUNCTION __extension__ __PRETTY_FUNCTION__ 193 # else 194 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L 195 # define __ASSERT_FUNCTION __func__ 196 # else 197 # define __ASSERT_FUNCTION ((const char *) 0) 198 # endif 199 # endif 200 201 #endif /* NDEBUG. */ 202 203 204 #if (defined __USE_ISOC11 \ 205 && (!defined __STDC_VERSION__ \ 206 || __STDC_VERSION__ <= 201710L \ 207 || !__GNUC_PREREQ (13, 0)) \ 208 && !defined __cplusplus) 209 # undef static_assert 210 # define static_assert _Static_assert 211 #endif
