Linux C/C++编程：prctl与pthread_setname_np

Myth丶恋晨 2023-01-01 08:51 252阅读 0赞

# prctl #

## 理论 ##

// 用 prctl 给线程命名, prctl是个系统调用
    #include <sys/prctl.h> 
    int prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5);

## 实践 ##

#include <zconf.h>
    #include <sys/prctl.h>
    #include <stdio.h>
    #include <pthread.h>
    
    void* tmain(void *arg)
    {
        
        char name[32];
        prctl(PR_SET_NAME, (unsigned long)"xx");
        prctl(PR_GET_NAME, (unsigned long)name);
        printf("%s/n", name);
        while (1)
            sleep(1);
    }
    int main(void)
    {
        
        pthread_t tid;
        pthread_create(&tid, NULL, tmain, NULL);
        pthread_join(tid, NULL);
        return 0;
    }

执行：

$ gcc main.c -l pthread
    $ ps aux | grep a.out
    oceanst+   9725  0.0  0.0  14704   384 pts/1    Sl+  18:52   0:00 ./a.out
    $  ps -L -p 9725
       PID    LWP TTY          TIME CMD
      9725   9725 pts/1    00:00:00 a.out
      9725   9726 pts/1    00:00:00 xx

# pthread\_setname\_np #

prctl()只能设置/获取当前线程的名字  
在glibc 2.12之后的版本中提供了两个扩展的接口pthread\_setname\_np()和pthread\_getname\_np()，可以在进程中设置和读取其他线程的名字。

检查glibc版本：

# getconf GNU_LIBC_VERSION
    glibc 2.17

可以使用feature\_test\_macro\_GNU\_SOURCE来检查此功能是否可用：

#ifdef _GNU_SOURCE
        pthread_setname_np(tid, "someName");
    #endif

## 理论 ##

#include <pthread.h>
    /*
    * 功能值：该pthread_setname_np（）函数设置目标线程的名称。由名称指定的缓冲区必须包含一个长度为15个字符或更少的空终止字符串（不包括NULL）。如果名称长度超过15个字符，则多余的字符将被忽略。如果name为null，则该线程变为未命名
    * 返回值：成功返回0
    */
     int pthread_setname_np(pthread_t thread, const char *name);
    //获取线程名称
    int pthread_getname_np(pthread_t thread, char *name);

## 实践 ##

#define _MULTI_THREADED
    #include <pthread.h>
    #include <stdio.h>
    #include <string.h>
    #include <unistd.h>
    
    void *threadfunc(void *parm)
    {
        
        printf("In the thread.\n");
        sleep(45);  // allow main program to set the thread name
        return NULL;
    }
    
    int main(int argc, char **argv)
    {
        
        pthread_t             thread;
        int                   rc=0;
        char                  theName[16];
    
        memset(theName, 0x00, sizeof(theName));
        printf("Create thread using the default attributes\n");
        rc = pthread_create(&thread, NULL, threadfunc, NULL);
        if(0 == rc)
        {
        
    #ifdef _GNU_SOURCE
            rc = pthread_setname_np(thread, "THREADNAMEISTOOLONG");
            sleep(10);
    
            if(0 == rc)
            {
        
                rc = pthread_getname_np(thread, theName);
                if(0 == rc)
                {
        
                    printf("The thread name is %s.\n", theName);
                }
            }
    #endif
            rc = pthread_join(thread, NULL);
        }
        if(0 != rc)
        {
        
            printf("An error occurred - %d\n", rc);
        }
        printf("Main completed\n");
        return(rc);
    }

[用prctl给线程命名][prctl]

[prctl]: https://www.cnblogs.com/sunyubo/archive/2010/12/10/2282086.html