fork - TGID, PID

fork_pt.c

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/unistd.h>

int main(void)
{
    int pid;
    
    printf("before fork \n \n");
    
    if((pid=fork()) < 0 ) {
        perror("fork error");
        exit(-2);
    } else if (pid == 0) {
        printf("TGID(%d), PID(%d) : Child \n", getpid(), syscall(__NR_gettid));
    } else {
        printf("TGID(%d), PID(%d) : Parent \n", getpid(), syscall(__NR_gettid));
        sleep(2);
    }
    
    printf("after fork \n \n");
    
    return 0;
}