file odd/even

#include <stdlib.h>
#include <unistd.h>

int separate(int fd_in, int fd_out_even, int fd_out_odd) {
    int32_t buf;
    int read_res;
    while ((read_res = read(fd_in, &buf, sizeof(buf))) > 0) {
        if (buf % 2 == 0) {
            if (write(fd_out_even, &buf, sizeof(buf)) != 4) {
                return -1;
            }
        } else {
            if (write(fd_out_odd, &buf, sizeof(buf)) != 4) {
                return -1;
            }
        }
    }
    return read_res;
}