c 创建线程

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

void *thread_body(void *arg) {
    printf("thread: pid = %d, thread_id = %lu\n", getpid(), pthread_self());
    return NULL;
}

int main () {

    pthread_t thread_id;
    printf("main: pid = %d, thread_id = %lu\n", getpid(), pthread_self());

    int res = pthread_create(&thread_id, NULL, thread_body, NULL);
    if (res != 0) {
        perror("pthread_create error");
    }
    pthread_exit(NULL);     // 退出main线程
}

线程间 共享 全局变量 

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

int var = 100;

void *thread_body(void *arg) {
    printf("thread: pid = %d, thread_id = %lu\n", getpid(), pthread_self());
    var = 999;
    return NULL;
}

int main () {
    printf("main: var = %d\n", var);
    
    pthread_t thread_id;
    printf("main: pid = %d, thread_id = %lu\n", getpid(), pthread_self());

    pthread_create(&thread_id, NULL, thread_body, NULL);

    sleep(1);

    printf("main: var = %d\n", var);
    return 0;
}

获取 线程的返回值

//
// Created by beokwithanything on 2020/11/17.
//
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include <sys/types.h>
#include <unistd.h>
#include "pthread.h"

struct thread {
    int var;
    char str[256];
};

void *thread_body(void *arg) {
    struct thread *t;

    t = malloc(sizeof(t));
    t->var = 200;
    strcpy(t->str, "hello thread!");

    return (void *)t;
}

int main () {

    pthread_t thread_id;
    int res = pthread_create(&thread_id, NULL, thread_body, NULL);
    if (res != 0) {
        perror("pthread_create error");
    }
    struct thread *tt;
    pthread_join(thread_id, (void **) &tt);
    printf("tt->var = %d, tt->str = '%s'\n", tt->var, tt->str);

    pthread_exit(NULL);
}