linux下用prctl函数给线程命名

在linux下开发的多线程系统中，如果没有设置新创建的线程的名字，则默认是进程的名字，这导致了每个线程的调试和监控比较麻烦，无法精准定位，为每个线程设置名字则比较好管理和调试。linux下的prctl库自kernel 2.6.9后开始支持PR_SET_NAME和PR_GET_NAME选项用于设置和获取进程名字，linux的线程一般采用lwp（light weight process，轻量级进程）来模拟，所以这个函数可以设置线程名字。

设置完成后可通过如下命令查看：ps -eL -o pid,user,lwp,comm

int prctl( int option,unsigned long arg2,unsigned long arg3,unsigned long arg4,unsigned long arg5);

PR_SET_NAME (since Linux 2.6.9)
Set the process name for the calling process, using the value in the location pointed to by (char *) arg2. The name can be up to 16 bytes long, and should be null-terminated if it contains fewer bytes.

PR_GET_NAME (since Linux 2.6.11)
Return the process name for the calling process, in the buffer pointed to by (char *) arg2. The buffer should allow space for up to 16 bytes; the returned string will be null-terminated if it is shorter than that.

#include <stdio.h>
#include <pthread.h>
#include <sys/prctl.h>

void *foo(void *arg)
{
    int idx = arg;
    printf("idx = %d\n", idx);
    switch(idx)
    {
        case 1:
        prctl(PR_SET_NAME, "ThreadName1");
        break;
        case 2:
        prctl(PR_SET_NAME, "ThreadName2");
        break;
        case 3:
        prctl(PR_SET_NAME, "ThreadName3");
        break;
        default:
        break;
    }

    sleep(50);
    return 0;
}

int main(void)
{
    pthread_t threadIdx[3];
    int threadArgIdx[] = {1, 2, 3};

    int i;
    for(i = 0; i < 3; i++)
    {
        pthread_create(threadIdx + i, NULL, foo, (void *)threadArgIdx[i]);
    }

    for(i = 0; i < 3; i++)
    {
        pthread_join(threadIdx[i], NULL);
    }
    return 0;
}

参考资料：
http://www.cppblog.com/lxyfirst/archive/2011/03/07/141288.aspx
http://blog.csdn.net/caspiansea/article/details/12073571