modernc.org/cc@v1.0.1/testdata/gcc-6.3.0/gcc/testsuite/gcc.c-torture/execute/builtins/lib/strlen.c (about)

     1  extern void abort (void);
     2  extern int inside_main;
     3  
     4  __attribute__ ((__noinline__))
     5  __SIZE_TYPE__
     6  strlen (const char *s)
     7  {
     8    __SIZE_TYPE__ i;
     9  
    10  #ifdef __OPTIMIZE__
    11    if (inside_main)
    12      abort ();
    13  #endif
    14  
    15    i = 0;
    16    while (s[i] != 0)
    17      i++;
    18  
    19    return i;
    20  }