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///+---------------------------------------------------------------------------
//
// File: DllSem.Hxx
//
// Contents: Semaphore classes
//
// Classes: CDLLStaticMutexSem - Mutex semaphore class For Dlls
// CDLLStaticLock - Safe Wrapper for lock...
//
// History: 11-Sep-92 Kurte Hacked up from AlexT's sources
//
// Notes: This file contains a hacked up version of the CMutexSem
// named CDllStataticMutexSem, which does not delete its
// critical section, when the DLL is unloaded, such that other
// dlls can still use the semaphore during their unload
// processing. This is to get around the NT less than
// optimal DLL Exit list processing...
//
//----------------------------------------------------------------------------
#ifndef __DLLSEM_HXX__
#define __DLLSEM_HXX__
#include <sem.hxx>
//+---------------------------------------------------------------------------
//
// Class: CDLLStaticMutexSem (dmxs)
//
// Purpose: Mutex Semaphore services
//
// Interface: Init - initializer (two-step)
// Request - acquire semaphore
// Release - release semaphore
//
// History: 14-Jun-91 AlexT Created.
// 30-oct-91 SethuR 32 bit implementation
//
// Notes: This class wraps a mutex semaphore. Mutex semaphores protect
// access to resources by only allowing one client through at a
// time. The client Requests the semaphore before accessing the
// resource and Releases the semaphore when it is done. The
// same client can Request the semaphore multiple times (a nest
// count is maintained).
// The mutex semaphore is a wrapper around a critical section
// which does not support a timeout mechanism. Therefore the
// usage of any value other than INFINITE is discouraged. It
// is provided merely for compatibility.
//
//----------------------------------------------------------------------------
class CDLLStaticMutexSem
{
public:
CDLLStaticMutexSem();
inline BOOL Init();
~CDLLStaticMutexSem();
SEMRESULT Request(DWORD dwMilliseconds = INFINITE);
void Release();
private:
CRITICAL_SECTION _cs;
};
//+---------------------------------------------------------------------------
//
// Class: CDLLStaticLock (dlck)
//
// Purpose: Lock using a Mutex Semaphore
//
// History: 02-Oct-91 BartoszM Created.
//
// Notes: Simple lock object to be created on the stack.
// The constructor acquires the semaphor, the destructor
// (called when lock is going out of scope) releases it.
//
//----------------------------------------------------------------------------
class CDLLStaticLock INHERIT_UNWIND_IF_CAIRO
{
DECLARE_UNWIND
public:
CDLLStaticLock ( CDLLStaticMutexSem& dmxs );
~CDLLStaticLock ();
private:
CDLLStaticMutexSem& _dmxs;
};
//+---------------------------------------------------------------------------
//
// Member: CDLLStaticMutexSem::CDLLStaticMutexSem, public
//
// Synopsis: Mutex semaphore constructor
//
// Effects: Initializes the semaphores data
//
// History: 14-Jun-91 AlexT Created.
//
//----------------------------------------------------------------------------
inline CDLLStaticMutexSem::CDLLStaticMutexSem()
{
Init();
}
inline CDLLStaticMutexSem::Init()
{
InitializeCriticalSection(&_cs);
return TRUE;
};
//+---------------------------------------------------------------------------
//
// Member: CDLLStaticMutexSem::~CDLLStaticMutexSem, public
//
// Synopsis: Mutex semaphore destructor
//
// Effects: Releases semaphore data
//
// History: 14-Jun-91 AlexT Created.
//
//----------------------------------------------------------------------------
inline CDLLStaticMutexSem::~CDLLStaticMutexSem()
{
// We can not delete the Critical Section as it may still
// Be called by someother DLL.
}
//+---------------------------------------------------------------------------
//
// Member: CDLLStaticMutexSem::Request, public
//
// Synopsis: Acquire semaphore
//
// Effects: Asserts correct owner
//
// Arguments: [dwMilliseconds] -- Timeout value
//
// History: 14-Jun-91 AlexT Created.
//
// Notes: Uses GetCurrentTask to establish the semaphore owner, but
// written to work even if GetCurrentTask fails.
//
//----------------------------------------------------------------------------
inline SEMRESULT CDLLStaticMutexSem::Request(DWORD dwMilliseconds)
{
dwMilliseconds;
EnterCriticalSection(&_cs);
return(SEMSUCCESS);
}
//+---------------------------------------------------------------------------
//
// Member: CDLLStaticMutexSem::Release, public
//
// Synopsis: Release semaphore
//
// Effects: Asserts correct owner
//
// History: 14-Jun-91 AlexT Created.
//
// Notes: Uses GetCurrentTask to establish the semaphore owner, but
// written to work even if GetCurrentTask fails.
//
//----------------------------------------------------------------------------
inline void CDLLStaticMutexSem::Release()
{
LeaveCriticalSection(&_cs);
}
//+---------------------------------------------------------------------------
//
// Member: CDLLStaticLock::CDLLStaticLock
//
// Synopsis: Acquire semaphore
//
// History: 02-Oct-91 BartoszM Created.
//
//----------------------------------------------------------------------------
inline CDLLStaticLock::CDLLStaticLock ( CDLLStaticMutexSem& dmxs )
: _dmxs ( dmxs )
{
_dmxs.Request ( INFINITE );
END_CONSTRUCTION (CDLLStaticLock);
}
//+---------------------------------------------------------------------------
//
// Member: CDLLStaticLock::~CDLLStaticLock
//
// Synopsis: Release semaphore
//
// History: 02-Oct-91 BartoszM Created.
//
//----------------------------------------------------------------------------
inline CDLLStaticLock::~CDLLStaticLock ()
{
_dmxs.Release();
}
#endif /* __DLLSEM_HXX__ */
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