blinky.c

#include <stdio.h>
#include <unistd.h>
#include <gpiod.h>

int main(int argc, char *argv[]) {
    int status = 0;

    // Check for root!
    if (geteuid() == 0) {
        for(;;) {
            gpiod_ctxless_set_value("gpiochip0", 12, status, 0, argv[0], NULL, NULL);
            sleep(1);
            status = !status;
        }
    } else {
        printf("Please run as root\n");
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}