/*
$ dcc spawn.c
$ a.out
Tue  3 Nov 23:51:27 UTC 2022
/bin/date exit status was 0
*/

// simple example of posix_spawn
// run date --utc to print current UTC

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <spawn.h>
#include <sys/wait.h>
#include <errno.h>
#include <string.h>

int main(void) {

    pid_t pid;
    extern char **environ;
    char *date_argv[] = {"date", "--utc", NULL};

    // spawn "date" as a separate process
    int ret = posix_spawnp(&pid, "date", NULL, NULL, date_argv, environ);
    
    if (ret != 0) {
        fprintf(stderr, "spawn: %s\n", strerror(ret));
        return 1;
    }

    // wait for spawned processes to finish
    int exit_status;
    if (waitpid(pid, &exit_status, 0) == -1) {
        perror("waitpid");
        return 1;
    }

    printf("/bin/date exit status was %d\n", exit_status);
    return 0;
}