gistfile1.c

#include <stdio.h>

void bar(void)
{
        printf("in bar\n");
}


char *foo(int a, void (*func)(void))
{
        (*func)();
        printf("in foo: %d\n", a);
        return "hoge";
}

int main(void)
{
        char *(*const x)(int, void(*)(void)) = foo;
        printf("in main: %s\n", x(100, bar));
        return 0;
}