#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>

#define RWRWRW (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)

int main(void){
    umask(0);
    if (creat("foo", RWRWRW) < 0){
        perror("creat error for foo");
    }
    // umask(S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
    umask(0707);
    if (creat("bar", RWRWRW) < 0){
        perror("creat error for bar");
    }

    exit(0);
}