리눅스 쓰레드 생성

thread.c

#define CLONE_VM 0x00000100 /* set if VM shared between processes */
#define CLONE_SIGHAND 0x00000800 /* set if signal handlers and blocked signals shared */
#define CLONE_THREAD 0x00010000 /* Same thread group? */

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define _GNU_SOURCE
#include <sched.h>

int g = 2;

int sub_func(void *arg)
{
    g++;
    printf("PID(%d) : Child g=%d \n", getpid(), g);
    sleep(2);
    return 0;
}

int main(void)
{
    int child_stack[4096];
    int l = 3;
    
    printf("PID(%d): Parent g=%d, l=%d \n", getpid(), g, l);
    
    clone(sub_func, (void *)(child_stack+4095), CLONE_VM | CLONE_THREAD | CLONE_SIGHAND, NULL);
    sleep(1);
    printf("PID(%d) : Parent g=%d, l=%d \n", getpid(), g, l);
    
    return 0;
}