Thread: An interesting bug on CLANG (at least in version 11)

Code:

#include <stdio.h>

static void (*ptr)(void) = NULL;

void f(void) { puts( "hello" ); }

void g(void) { ptr = f; }

int main( void ) { ptr(); }

In clang, strange as it seems, this code will print "hello" (but g() is never called, how is this possible?).

Ok... derreferencing a NULL pointer is a UB... but every other compiler gives us an 'segmentation fault' or 'access violation'. Why clang initializes ptr with f, instead of the explicit (void *)0?

Take 'static' off and the code behaves as expected.