ReadWrite lock using Boost.Threads (how to convert this simple class)
I am porting some code from windows to Linux (Ubuntu 9.10). I have a simple class (please see below), which uses windows functions to implement simple mutex locking. I want to use Boost.Threads to reimplement this, but that library is new to me.
Can someone point out the changes I need to make to the class below, in order tomuse Boost.Threads instead of the WIN specific functions?
#ifndef __my_READWRITE_LOCK_Header__
#define __my_READWRITE_LOCK_Header__
#include <windows.h>
//Simple RW lock implementation is shown below.
#define RW_READERS_MAX 10
#define RW_MAX_SEMAPHORE_COUNT 10
#define RW_MUTEX_NAME L"mymutex"
#define RW_SEMAPHORE_NAME L"mysemaphore"
class CThreadRwLock
{
public:
CThreadRwLock()
{
InitializeCriticalSection(&m_cs);
m_hSem = CreateSemaphore(0, RW_READERS_MAX, RW_READERS_MAX, 0);
}
~CThreadRwLock()
{
DeleteCriticalSection(&m_cs);
CloseHandle(m_hSem);
}
void AcquireReaderLock()
{
EnterCriticalSection(&m_cs);
WaitForSingleObject(m_hSem, INFINITE);
LeaveCriticalSection(&m_cs);
}
void AcquireWriterLock()
{
EnterCriticalSection(&m_cs);
for(int i = 0; i < RW_READERS_MAX; i++)
{
WaitForSingleObject(m_hSem, INFINITE);
}
LeaveCriticalSection(&m_cs);
}
void ReleaseReaderLock()
{
ReleaseSemaphore(m_hSem, 1, 0);
}
void ReleaseWriterLock()
{
ReleaseSemaphore(m_hSem, R开发者_Python百科W_READERS_MAX, 0);
}
private:
CRITICAL_SECTION m_cs;
HANDLE m_hSem;
};
class CProcessRwLock
{
public:
CProcessRwLock()
{
m_h = CreateMutex(NULL, FALSE, RW_MUTEX_NAME);
m_hSem = CreateSemaphore(NULL, RW_MAX_SEMAPHORE_COUNT, RW_MAX_SEMAPHORE_COUNT, RW_SEMAPHORE_NAME);
}
~CProcessRwLock()
{
CloseHandle(m_h);
}
void AcquireReaderLock()
{
WaitForSingleObject(m_h, INFINITE);
ReleaseMutex(m_h);
}
void AcquireWriterLock()
{
WaitForSingleObject(m_h, INFINITE);
for(int i = 0; i < RW_READERS_MAX; i++)
{
WaitForSingleObject(m_hSem, INFINITE);
}
ReleaseMutex(m_h);
}
void ReleaseReaderLock()
{
ReleaseSemaphore(m_hSem, 1, 0);
}
void ReleaseWriterLock()
{
ReleaseSemaphore(m_hSem, RW_READERS_MAX, 0);
}
private:
HANDLE m_h, m_hSem;
};
class AutoThreadRwLock
{
public:
AutoThreadRwLock(const bool readlock = true):m_readlock(readlock)
{
if (readlock)
m_lock.AcquireReaderLock();
else
m_lock.AcquireWriterLock();
}
~AutoThreadRwLock()
{
if (m_readlock)
m_lock.ReleaseReaderLock();
else
m_lock.ReleaseWriterLock();
}
private:
AutoThreadRwLock(const AutoThreadRwLock&);
AutoThreadRwLock& operator= (const AutoThreadRwLock& );
CThreadRwLock m_lock ;
bool m_readlock ;
};
class AutoProcessRwLock
{
public:
AutoProcessRwLock(const bool readlock = true): m_readlock(readlock)
{
if (readlock)
m_lock.AcquireReaderLock();
else
m_lock.AcquireWriterLock();
}
~AutoProcessRwLock()
{
if (m_readlock)
m_lock.ReleaseReaderLock();
else
m_lock.ReleaseWriterLock();
}
private:
AutoProcessRwLock(const AutoProcessRwLock&);
AutoProcessRwLock& operator= (const AutoProcessRwLock&);
CProcessRwLock m_lock ;
bool m_readlock ;
};
#endif //__my_READWRITE_LOCK_Header__
I'm not going to re-write all your code for you. However you should look into boost's shared_mutex class.
Also, this question from StackOverflow shows how to use a boost::shared_mutex
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