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使用boost.threads的condition構造的讀寫鎖

沒有什么實際意義（boost.threads已經加入了讀寫鎖好像），只是說明一下condition的用法。
鎖由Mutex和Lock構成。
Mutex是由condition實作而成的，Lock和ScopedLock區別不是很大，分讀寫鎖而已。

以下是Mutex的代碼

class?read_write_mutex

{

????mutex?mtx_;

????int?read_cnt_;

????condition?cond_;

public:

????read_write_mutex():?read_cnt_(0){}

????~read_write_mutex(){}

????void?lock_read(){

????????mutex::scoped_lock?lock(mtx_);

????????while(read_cnt_?<?0){

????????????cond_.wait(lock);

????????}

????????++read_cnt_;

????}

????

????void?unlock_read(){

????????mutex::scoped_lock?lock(mtx_);

????????--read_cnt_;

????????cond_.notify_all();

????}

????void?lock_write(){

????????mutex::scoped_lock?lock(mtx_);

????????while(read_cnt_?!=?0){

????????????cond_.wait(lock);

????????}

????????read_cnt_?=?-1;

????}

????void?unlock_write(){

????????mutex::scoped_lock?lock(mtx_);

????????read_cnt_?=?0;

????????cond_.notify_all();

????}

};

以下是鎖的代碼

class?scoped_rlock

{

????read_write_mutex&?cond_;

public:

????scoped_rlock(read_write_mutex&?c):cond_(c){cond_.lock_read();}

????~scoped_rlock(){cond_.unlock_read();}

};

class?scoped_wlock

{

????read_write_mutex&?cond_;

public:

????scoped_wlock(read_write_mutex&?c):cond_(c){cond_.lock_write();}

????~scoped_wlock(){cond_.unlock_write();}

};

以下是測試用例：

int?top?=?0;

int?stack[1000];

read_write_mutex?rwc;

mutex?io_mutex;

void?read(int?val)

{

????for(int?i?=?0;?i?<?20;?++i)

????{

????????Sleep(2);

????????scoped_rlock?rlock(rwc);

????????int?s?=?top;

????????{

????????????mutex::scoped_lock?lock(io_mutex);

????????????cout?<<?"read?begin?"?<<?val?<<?endl;

????????}

????????Sleep(10);

????????{

????????????mutex::scoped_lock?lock(io_mutex);

????????????cout?<<?"read?end?"?<<?val?<<?endl;

????????}

????????if(s?!=?top)

????????{

????????????cout?<<?"error!"<<endl;

????????}

????}

}

void?write(int?val)

{

????for(int?i?=?0;?i?<?20;?++i)

????{

????????Sleep(2);

????????scoped_wlock?wlock(rwc);

????????{

????????????mutex::scoped_lock?lock(io_mutex);

????????????cout?<<?"write?begin?"?<<?val?<<?endl;

????????}

????????Sleep(5);

????????{

????????????mutex::scoped_lock?lock(io_mutex);

????????????cout?<<?"write?end?"?<<?val?<<?endl;

????????}

????}

}

int?_tmain(int?argc,?_TCHAR*?argv[])

{

????thread_group?rtg;

????for(int?i?=?0;?i?<?10;?++i)

????{

????????rtg.create_thread(boost::bind(&read,?i));

????}

????for(int?i?=?0;?i?<?2;?++i)

????{

????????rtg.create_thread(boost::bind(&write,?i));

????}

????rtg.join_all();

????system("pause");

????return?0;

}

別忘了頭文件中：

#include?<boost/thread.hpp>

#include?<boost/bind.hpp>

#include?<windows.h>

#include?<iostream>

using?namespace?std;

using?namespace?boost;

posted on 2006-10-23 19:38 空明流轉閱讀(1818) 評論(0) 編輯收藏引用

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