// ------------------------------- //
// -------- Start of File -------- //
// ------------------------------- //
// ----------------------------------------------------------- //
// C++ Source Code File Name: testprog.cpp
// Compiler Used: MSVC, BCC32, GCC, HPUX aCC, SOLARIS CC
// Produced By: glNET Software
// File Creation Date: 03/25/2000
// Date Last Modified: 05/25/2001
// Copyright (c) 2001 glNET Software
// ----------------------------------------------------------- //
// ------------- Program Description and Details ------------- //
// ----------------------------------------------------------- //
/*
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA
Test program demonstrating the basic operation of the gxThread
class using mutex and condition variable synchronization
primitives.
*/
// ----------------------------------------------------------- //
#include <iostream.h>
#include "gxthread.h"
#include "gxmutex.h"
#include "gxcond.h"
#ifdef __MSVC_DEBUG__
#include "leaktest.h"
#endif
// Constants
const int NUMTHREADS = 2;
// Global synchronization objects
gxMutex dataMutex;
gxCondition dataPresentCondition;
// Global variables
int dataPresent = 0;
int sharedData = 0;
class ConsumerThread : public gxThread
{
private: // Base class interface
void *ThreadEntryRoutine(gxThread_t *thread);
};
void *ConsumerThread::ThreadEntryRoutine(gxThread_t *thread)
// Thread's entry function
{
int retries = 1;
cout << "Entering consumer thread" << endl;
if(dataMutex.MutexLock() != 0) {
cout << "Consumer thread mutex lock failed!" << endl;
cout << dataMutex.MutexExceptionMessage() << endl;
return ExitThread(thread, 1);
}
while(retries--) {
// The boolean dataPresent value is required for safe use of
// condition variables. If no data is present we wait, other
// wise we process immediately.
while(!dataPresent) {
cout << "Consumer thread waiting for data to be produced" << endl;
if(dataPresentCondition.ConditionWait(&dataMutex) != 0) {
cout << "Consumer thread condition wait failed!" << endl;
cout << dataPresentCondition.ConditionExceptionMessage() << endl;
dataMutex.MutexUnlock();
return ExitThread(thread, 1);
}
}
cout << "Consumer thread found data or notified" << endl;
cout << "CONSUME DATA while holding lock" << endl;
// Typically an application should remove the data from being
// in the shared structure or Queue, then unlock. Processing
// of the data does not necessarily require that the lock is held
// Access to shared data goes here
--sharedData;
// We consumed the last of the data
if(sharedData == 0) dataPresent = 0;
// Repeat holding the lock.
// The gxCondition::ConditionWait() function releases it atomically
}
cout << "Consumer thread done" << endl;
if(dataMutex.MutexUnlock() != 0) {
cout << "Consumer thread mutex unlock failed!" << endl;
cout << dataMutex.MutexExceptionMessage() << endl;
return ExitThread(thread, 1);
}
return 0;
}
// Program's main thread of execution
int main()
{
#ifdef __MSVC_DEBUG__
InitLeakTest();
#endif
ConsumerThread t;
gxThread_t *thread[NUMTHREADS];
int amountOfData = 4;
int i;
cout << "Create/start threads" << endl;
for(i = 0; i < NUMTHREADS; ++i) {
thread[i] = t.CreateThread();
if(thread[i]->GetThreadError() != gxTHREAD_NO_ERROR)
cout << thread[i]->ThreadExceptionMessage() << endl;
}
// The producer loop
while(amountOfData--) {
cout << "Producer finding data..." << endl;
t.sSleep(1);
if(dataMutex.MutexLock() != 0) { // Protect shared data and flag
cout << "Producer thread mutex lock failed!" << endl;
cout << dataMutex.MutexExceptionMessage() << endl;
}
cout << "Producer thread make data shared and notify consumer" << endl;
++sharedData; // Add data
dataPresent = 1; // Set boolean predicate
// Wake up a consumer
if(dataPresentCondition.ConditionSignal() != 0) {
cout << "Producer thread condition signal failed!" << endl;
cout << dataPresentCondition.ConditionExceptionMessage() << endl;
dataMutex.MutexUnlock();
return 1;
}
cout << "Producer thread unlock shared data and flag" << endl;
if(dataMutex.MutexUnlock() != 0) {
cout << "Producer thread mutex unlock failed!" << endl;
cout << dataMutex.MutexExceptionMessage() << endl;
}
}
cout << "Wait for the threads to complete, and release their resources"
<< endl;
for(i = 0; i < NUMTHREADS; i++) {
if(t.JoinThread(thread[i]) != 0)
cout << "Could not join the thread" << endl;
if(thread[i]->GetThreadExitCode() != 0)
cout << "This thread exited with an error" << endl;
}
// Release any memory the thread is still holding
for(i = 0; i < NUMTHREADS; i++) {
if(t.DestroyThread(thread[i]) != 0) {
cout << "Error destroying thread!" << endl;
}
}
return 0;
}
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