gcc/testsuite/g++.dg/ext/builtin30.C

// { dg-do compile }
// { dg-options "-O2" }

typedef __SIZE_TYPE__ size_t;
extern "C" {
extern void __chk_fail (void);
extern int snprintf (char *, size_t, const char *, ...);
extern inline __attribute__((gnu_inline, always_inline)) int snprintf (char *a, size_t b, const char *fmt, ...)
{
  if (__builtin_object_size (a, 0) != -1UL && __builtin_object_size (a, 0) < b)
    __chk_fail ();
  return __builtin_snprintf (a, b, fmt, __builtin_va_arg_pack ());
}
extern int snprintf (char *, size_t, const char *, ...) __asm ("mysnprintf");
}

char buf[10];

int
main (void)
{
  snprintf (buf, 10, "%d%d\n", 10, 10);
  return 0;
}

// { dg-final { scan-assembler "mysnprintf" } }
// { dg-final { scan-assembler-not "__chk_fail" } }