linux thread

#include<pthread.h>
#include<stdio.h>

pthread_t ntid;


void printids(const char *s)
{
        pid_t pid;
        pthread_t tid;

        pid=getpid();
        tid=pthread_self();
        printf("%s pid %u tid %u (0x%x)\n",s,(unsigned int)pid,
            (unsigned int)tid,(unsigned int)tid);

}

void *thr_fn(void *arg)
{
        printids("new thread: ");
        return ((void *)0);

}

int main(void)
{
        int err;
        err = pthread_create(&ntid,NULL,thr_fn,NULL);
        printf("ntid= %d",ntid);
        if(err!=0)
            printf("can't create thread : %s\n");
        printids("main thread:");
        sleep(1);
        exit(0);

}

编译时候需添加-pthread选项，或者-lpthread选项，否则出现undefined reference to 'pthread_create’

因为默认情况下pthread_create不是linux系统默认连接的库

关于-pthread与-lpthread选项区别可以参见此文

http://chaoslawful.iteye.com/blog/568602

推荐用-pthread选项(compile and link with -pthread flag)

pthread返回的第一个参数为指向线程标识符的指针，第三个参数为start routine，即线程执行函数的起始地址