musl/include/assert.h

#include <features.h>

#undef assert

#ifdef NDEBUG
#define	assert(x) (void)0
#else
#define assert(x) ((void)((x) || (__assert_fail(#x, __FILE__, __LINE__, __func__),0)))
#endif

#ifdef __cplusplus
extern "C" {
#endif

void __assert_fail (const char *, const char *, int, const char *);

#ifdef __cplusplus
}
#endif
default features: make musl usable without feature test macros the old behavior of exposing nothing except plain ISO C can be obtained by defining __STRICT_ANSI__ or using a compiler option (such as -std=c99) that predefines it. the new default featureset is POSIX with XSI plus _BSD_SOURCE. any explicit feature test macros will inhibit the default. installation docs have also been updated to reflect this change. 2012-09-08 07:13:55 +04:00			`#include <features.h>`
initial check-in, version 0.5.0 2011-02-12 08:22:29 +03:00
default features: make musl usable without feature test macros the old behavior of exposing nothing except plain ISO C can be obtained by defining __STRICT_ANSI__ or using a compiler option (such as -std=c99) that predefines it. the new default featureset is POSIX with XSI plus _BSD_SOURCE. any explicit feature test macros will inhibit the default. installation docs have also been updated to reflect this change. 2012-09-08 07:13:55 +04:00			`#undef assert`
further use of _Noreturn, for non-plain-C functions note that POSIX does not specify these functions as _Noreturn, because POSIX is aligned with C99, not the new C11 standard. when POSIX is eventually updated to C11, it will almost surely give these functions the _Noreturn attribute. for now, the actual _Noreturn keyword is not used anyway when compiling with a c99 compiler, which is what POSIX requires; the GCC __attribute__ is used instead if it's available, however. in a few places, I've added infinite for loops at the end of _Noreturn functions to silence compiler warnings. presumably __buildin_unreachable could achieve the same thing, but it would only work on newer GCCs and would not be portable. the loops should have near-zero code size cost anyway. like the previous _Noreturn commit, this one is based on patches contributed by philomath. 2012-09-07 07:34:10 +04:00
initial check-in, version 0.5.0 2011-02-12 08:22:29 +03:00			`#ifdef NDEBUG`
			`#define assert(x) (void)0`
			`#else`
assert() is supposed to have type void 2012-10-17 10:47:11 +04:00			`#define assert(x) ((void)((x) \|\| (__assert_fail(#x, __FILE__, __LINE__, __func__),0)))`
initial check-in, version 0.5.0 2011-02-12 08:22:29 +03:00			`#endif`

			`#ifdef __cplusplus`
			`extern "C" {`
			`#endif`

__assert_fail(): remove _Noreturn, to get proper stacktraces for _Noreturn functions, gcc generates code that trashes the stack frame, and so it makes it impossible to inspect the causes of an assert error in gdb. abort() is not affected (i have not yet investigated why). 2013-01-01 10:59:11 +04:00			`void __assert_fail (const char , const char , int, const char *);`
initial check-in, version 0.5.0 2011-02-12 08:22:29 +03:00
			`#ifdef __cplusplus`
			`}`
			`#endif`