#include <stdio.h>
#include <unistd.h>

int foo(int *bar);
int main()
{
	int a=0;
#ifdef _POSIX_VERSION
	printf("System conforms to POSIX: %d\n", _POSIX_VERSION);
#else
	printf("POSIX version is undefined.\n");
#endif
	foo(&a);
	printf("%d\n",a);
	return foo(&a);
}

int foo(int *bar)
{
	*bar=1;
}