#include <fcntl.h>
#include <stdio.h>

int main() {
    int fd = open("testfile", O_RDONLY);
    if (fd == -1) {
        perror("open");
        return 1;
    }

    int flags = fcntl(fd, F_GETFD);
    if (flags == -1) {
        perror("fcntl");
        return 1;
    }

    if (flags & FD_CLOEXEC) {
        printf("O_CLOEXEC is supported.\n");
    } else {
        printf("O_CLOEXEC is not supported.\n");
    }

    close(fd);
    return 0;
}