#include <string.h>
struct test {
int a;
char b;
int c;
};
extern int copy_to_user(void *dest, void *src, size_t size);
void do_stuff(void *usr_buf) {
struct test arg;
memset(&arg, 0, sizeof(arg));
arg.a = 1;
arg.b = 2;
arg.c = 3;
copy_to_user(usr_buf, &arg, sizeof(arg));
}