Pointer to undeclared structure-type considered ok?
Nick Patavalis
npat@inaccessnetworks.com
Wed Feb 2 14:23:00 GMT 2005
Accidentally I attempted to compile a program like the one shown
below, and I was totally amazed by the fact that the compiler produced
*no errors* and *no warnings*. Is this valid C? Wouldn't at least a
warning be in order here?
#include <stdlib.h>
#include <stdio.h>
struct foo {
int a;
struct bar *b;
};
struct foo foo;
int
main (void)
{
foo.a = 0;
foo.b = NULL;
printf("foo.a = %d\n", foo.a);
printf("foo.b = %p\n", foo.b);
return 0;
}
and compiled like this:
gcc -Wall tst.c -o tst
[ ... no errors or warnings!! ... ]
and also runs fine (which is not surprising):
./tst
foo.a = 0
foo.b = (nil)
I used GCC-3.3.4, the one that comes with the current debian-sarge,
specifically:
gcc --version
gcc (GCC) 3.3.4 (Debian 1:3.3.4-13)
Copyright (C) 2003 Free Software Foundation, Inc.
...
Is this a bug in GCC?
/npat
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