gcc/testsuite/gcc.dg/func-outside-1.c

/* Test for rejection of __func__ outside a function (GNU extensions
   are OK there).  Test with no special options.  */
/* Origin: Joseph Myers <joseph@codesourcery.com> */
/* { dg-do compile } */
/* { dg-options "-fshow-column" } */

const char *a = __func__; /* { dg-warning "17:'__func__' is not defined outside of function scope" "undef" } */
const char *b = __FUNCTION__;
const char *c = __PRETTY_FUNCTION__;