mingw无法编译多线程程序的问题及解决

在linux环境下，用gedit+gcc方式学习一段时间的c语言，发现自己越来越佩服linux的牛人了。
居然不用IDE也能开发代码。我做不到，所以有回到了windows的怀抱。

mingw是windows版本的gnu c/c++工具集 主要包括编译器gcc,连接器make，调试器gdb
Eclipse是很好用的开发Java的IDE，CDT的全称是C/C++ Development Tools，是使Eclipse能够支持C/C++开发的插件。
本人使用的开发环境如下:
win7+eclipse +MinGW + CDT

本文的目的：
1）使用eclipse、MingW独构建Windows版的c/c++开发环境
2）编译并调通了一个多线程的程序
eclipse、MingW的安装此处不做重点。


1、配置C/C++开发环境
右击我的电脑，点属性->高级->环境变量。然后：
1）在PATH里加入C:\MinGW\bin
2）新建LIBRARY_PATH变量，值设为C:\MinGW\lib，这是标准库的位置。
3）新建C_INCLUDE_PATH变量，值设为C:\MinGW\include。
4）新建CPLUS_INCLUDE_PATH变量，值为C:\MinGW\include\c++\3.4.2;C:\MinGW\include\c++\3.4.2\mingw32;C:\MinGW\include\c++\3.4.2\backward;C:\MinGW\include


2、设置eclipse的环境变量
Eclipse的Project->Properties->C/C++ Build->Environment中去查看对应的PATH变量
主要是看有没有添加一个包含MinGW的bin目录的PATH变量。这个变量在创建工程的时候一般会自动添加。
但如果没有正确设置PATH变量，编译的时候就会报错说不能运行g++或者gcc。

3、设置多线程动态链接库
Project->Properties->C/C++Build->Settings->Tool Settings->GCC C++ Linker->Libraries
添加Libraries (-l): lpthread

4、一个简单的线程池的例子

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

typedef struct worker
{
  
    void *(*process) (void *arg);
    void *arg;
    struct worker *next;


} CThread_worker;


typedef struct
{
pthread_mutex_t queue_lock;
pthread_cond_t queue_ready;

     CThread_worker *queue_head;
    int shutdown;
     pthread_t *threadid;
  
    int max_thread_num;
  
    int cur_queue_size;


} CThread_pool;


int pool_add_worker (void *(*process) (void *arg), void *arg);
void *thread_routine (void *arg);


static CThread_pool *pool = NULL;
void
pool_init (int max_thread_num)
{
     pool = (CThread_pool *) malloc (sizeof (CThread_pool));


     pthread_mutex_init (&(pool->queue_lock), NULL);
     pthread_cond_init (&(pool->queue_ready), NULL);

     pool->queue_head = NULL;

     pool->max_thread_num = max_thread_num;
     pool->cur_queue_size = 0;

     pool->shutdown = 0;
     pool->threadid =
         (pthread_t *) malloc (max_thread_num * sizeof (pthread_t));
    int i = 0;
    for (i = 0; i < max_thread_num; i++)
     {
         pthread_create (&(pool->threadid[i]), NULL, thread_routine,
                 NULL);
     }
}


int
pool_add_worker (void *(*process) (void *arg), void *arg)
{
  
     CThread_worker *newworker =
         (CThread_worker *) malloc (sizeof (CThread_worker));
     newworker->process = process;
     newworker->arg = arg;
     newworker->next = NULL;

     pthread_mutex_lock (&(pool->queue_lock));
  
     CThread_worker *member = pool->queue_head;
    if (member != NULL)
     {
        while (member->next != NULL)
             member = member->next;
         member->next = newworker;
     }
    else
     {
         pool->queue_head = newworker;
     }


     assert (pool->queue_head != NULL);


     pool->cur_queue_size++;
     pthread_mutex_unlock (&(pool->queue_lock));
  
     pthread_cond_signal (&(pool->queue_ready));
    return 0;
}


int
pool_destroy ()
{
    if (pool->shutdown)
        return -1;
     pool->shutdown = 1;

     pthread_cond_broadcast (&(pool->queue_ready));
  
    int i;
    for (i = 0; i < pool->max_thread_num; i++)
         pthread_join (pool->threadid[i], NULL);
     free (pool->threadid);


  
     CThread_worker *head = NULL;
    while (pool->queue_head != NULL)
     {
         head = pool->queue_head;
         pool->queue_head = pool->queue_head->next;
         free (head);
     }
  
     pthread_mutex_destroy(&(pool->queue_lock));
     pthread_cond_destroy(&(pool->queue_ready));

     free (pool);
  
     pool=NULL;
    return 0;
}


void * thread_routine (void *arg)
{
     printf ("starting thread 0x%x\n", pthread_self ());
    while (1)
     {
         pthread_mutex_lock (&(pool->queue_lock));
      
        while (pool->cur_queue_size == 0 && !pool->shutdown)
         {
             printf ("thread 0x%x is waiting\n", pthread_self ());
             pthread_cond_wait (&(pool->queue_ready), &(pool->queue_lock));
         }


      
        if (pool->shutdown)
         {
          
             pthread_mutex_unlock (&(pool->queue_lock));
             printf ("thread 0x%x will exit\n", pthread_self ());
             pthread_exit (NULL);
         }


         printf ("thread 0x%x is starting to work\n", pthread_self ());


      
         assert (pool->cur_queue_size != 0);
         assert (pool->queue_head != NULL);

      
         pool->cur_queue_size--;
         CThread_worker *worker = pool->queue_head;
         pool->queue_head = worker->next;
         pthread_mutex_unlock (&(pool->queue_lock));


      
         (*(worker->process)) (worker->arg);
         free (worker);
         worker = NULL;
     }
     pthread_exit (NULL);
}


   // 下面是测试代码

void * myprocess (void *arg)
{
     printf ("threadid is 0x%x, working on task %d\n", pthread_self (),*(int *) arg);
     _sleep (1);
    return NULL;
}


int main (int argc, char **argv)
{
     pool_init (3);

  
    int *workingnum = (int *) malloc (sizeof (int) * 10);
    int i;
    for (i = 0; i < 10; i++)
     {
         workingnum[i] = i;
         pool_add_worker (myprocess, &workingnum[i]);
     }
  
     _sleep (5);
  
     pool_destroy ();


     free (workingnum);
    return 0;
}


5、问题及解决方法
1）build project时出现“Error launching builder (make -k all )”
先将C:\MinGW\bin底下的
mingw32-make.exe更名为make.exe，因为在Eclipse使用时它预设会抓系统里make这个文件名而不是mingw32-make.

2）build project时出现“launch failed,binary not found”
报错是因为没有指定编译器。为了让CDT能够采用MinGW进行编译，需要在 Eclipse 中进行设定
方法一：去Window->Preferences->C/C++->New CDT project wizard->Makefile Project下，找到 Binary Parser 取消 Elf Parser 改选 PE Windows Parser。或是其他编译器，看具体情况而定，
当然你也可以指定GNU ELF Parser。
方法二：去projrct -> properties -> c/c++ build -> settings ->Binary Parser下设置一下，比如使用GNU Elf Parser


3）undefined reference to 'pthread_create'
   undefined reference to 'pthread_join'
问题原因：
pthread 库不是 Linux 系统默认的库，由于Mingw下没有带，所以在项目中设置多线程动态链接库，也不管用。
ftp://sourceware.org/pub/pthreads-win32/pthreads-w32-2-8-0-release.exe
解开pthreads-w32-2-8-0-release.exe，把Pre- built.2中的libpthreadGC2.a改名为libpthread.a复制到c:\mingw\lib目录，
pthread.h复制到c: \mingw\include目录即可解决


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作者：流星
出处：http://blog.sina.com.cn/staratsky