mingw無法編譯多執行緒程式的問題及解決
在linux環境下,用gedit+gcc方式學習一段時間的c語言,發現自己越來越佩服linux的牛人了。
居然不用IDE也能開發程式碼。我做不到,所以有回到了windows的懷抱。
mingw是windows版本的gnu c/c++工具集 主要包括編譯器gcc,聯結器make,偵錯程式gdb
Eclipse是很好用的開發Java的IDE,CDT的全稱是C/C++ DevelopmentTools,是使Eclipse能夠支援C/C++開發的外掛。
本人使用的開發環境如下:
win7+eclipse +MinGW + CDT
本文的目的:
1)使用eclipse、MingW獨構建Windows版的c/c++開發環境
2)編譯並調通了一個多執行緒的程式
eclipse、MingW的安裝此處不做重點。
1、配置C/C++開發環境
右擊我的電腦,點屬性->高階->環境變數。然後:
1)在PATH里加入C:\MinGW\bin
2)新建LIBRARY_PATH變數,值設為C:\MinGW\lib,這是標準庫的位置。
3)新建C_INCLUDE_PATH變數,值設為C:\MinGW\include。
4)新建CPLUS_INCLUDE_PATH變數,值為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、設定eclipse的環境變數
主要是看有沒有新增一個包含MinGW的bin目錄的PATH變數。這個變數在建立工程的時候一般會自動新增。
但如果沒有正確設定PATH變數,編譯的時候就會報錯說不能執行g++或者gcc。
3、設定多執行緒動態連結庫
Project->Properties->C/C++Build->Settings->ToolSettings->GCC C++Linker->Libraries
新增Libraries (-l): lpthread
4、一個簡單的執行緒池的例子
#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;
structworker *next;
} CThread_worker;
typedef struct
{
pthread_mutex_t queue_lock;
pthread_cond_t queue_ready;
CThread_worker *queue_head;
intshutdown;
pthread_t *threadid;
intmax_thread_num;
intcur_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));
return0;
}
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;
return0;
}
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);
}
// 下面是測試程式碼
void * myprocess (void *arg)
{
printf ("threadid is 0x%x, working on task %d\n", pthread_self(),*(int *) arg);
_sleep (1);
returnNULL;
}
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);
return0;
}
5、問題及解決方法
1)build project時出現“Error launchingbuilder (make -k all )”
先將C:\MinGW\bin底下的
mingw32-make.exe更名為make.exe,因為在Eclipse使用時它預設會抓系統裡make這個檔名而不是mingw32-make.
2)build project時出現“launch failed,binary not found”
報錯是因為沒有指定編譯器。為了讓CDT能夠採用MinGW進行編譯,需要在 Eclipse 中進行設定
方法一:去Window->Preferences->C/C++->NewCDT project wizard->Makefile Project下,找到 BinaryParser 取消 Elf Parser 改選 PE Windows Parser。或是其他編譯器,看具體情況而定,
當然你也可以指定GNU ELF Parser。
方法二:去projrct -> properties -> c/c++build -> settings ->BinaryParser下設定一下,比如使用GNU Elf Parser
3)undefined reference to 'pthread_create'
undefined reference to'pthread_join'
問題原因:
pthread 庫不是 Linux 系統預設的庫,由於Mingw下沒有帶,所以在專案中設定多執行緒動態連結庫,也不管用。
ftp://sourceware.org/pub/pthreads-win32/pthreads-w32-2-8-0-release.exe
解開pthreads-w32-2-8-0-release.exe,把Pre-built.2中的libpthreadGC2.a改名為libpthread.a複製到c:\mingw\lib目錄,
pthread.h複製到c: \mingw\include目錄即可解決