Multithreading programing in Win32 - c++

Question

I use mutex to sync file writing and reading. I create some threads to read file and some threads to write file. But writing Thread sometimes block in WaitForSingleObject(hMutexRW,INFINITE). I'm new to Win32 Threads programming and I don't know what the problem is. I think the mutex is the problem, and I want to know how to solve this problem.
const int nThreadWriting = 5;
const int nThreadReading = 5;
const int nBufSize = 100;
const int maxWritten = 10;
const int timeRange = 3;
HANDLE hMutexRW, hMutexW, hMutexR, hMutexN;
int currentSemaphoreR = 0;
int numberWritten = 0;
unsigned __stdcall ThreadReading(void *pV)
{
HANDLE hFile;
int waitTime, lastTime;
char buf[nBufSize];
int* ptr = (int*)pV;
srand(*ptr);
while (1)
{
WaitForSingleObject(hMutexN, INFINITE);
if (numberWritten >= maxWritten)
{
ReleaseMutex(hMutexN);
return 0;
}
ReleaseMutex(hMutexN);
waitTime = rand() % timeRange+1;
lastTime = rand() % timeRange+1;
WaitForSingleObject(hMutexW, INFINITE);
WaitForSingleObject(hMutexR, INFINITE);
if (currentSemaphoreR == 0)
{
WaitForSingleObject(hMutexRW, INFINITE);
sprintf_s(buf, nBufSize, "%d R GET MUTEX_RW\n", GetCurrentThreadId());
std::cout << buf << std::endl;
}
currentSemaphoreR++;
ReleaseMutex(hMutexR);
ReleaseMutex(hMutexW);
hFile = CreateFile(TEXT("nice.txt"), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile == INVALID_HANDLE_VALUE)
{
std::cout << "cannot open file" << std::endl;
}
sprintf_s(buf, nBufSize, "%d R %d %d\n", GetCurrentThreadId(), waitTime, lastTime);
std::cout << buf <<std::endl;
CloseHandle(hFile);
WaitForSingleObject(hMutexR, INFINITE);
currentSemaphoreR--;
if (currentSemaphoreR == 0)
ReleaseMutex(hMutexRW);
ReleaseMutex(hMutexR);
}
return 0;
}
unsigned __stdcall ThreadWriting(void *pV)
{
int waitTime, lastTime;
char buf[nBufSize];
int* ptr = (int*)pV;
srand(*ptr);
HANDLE hFile;
while (1)
{
WaitForSingleObject(hMutexN, INFINITE);
if (numberWritten >= maxWritten)
{
ReleaseMutex(hMutexN);
return 0;
}
numberWritten++;
ReleaseMutex(hMutexN);
WaitForSingleObject(hMutexW, INFINITE);
WaitForSingleObject(hMutexRW, INFINITE);
hFile = CreateFile(TEXT("nice.txt"), GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile == INVALID_HANDLE_VALUE)
{
std::cout << "cannot open file" << std::endl;
return 1;
}
SetFilePointer(hFile, 0, NULL, FILE_END);
sprintf_s(buf, nBufSize, "%d W %d %d\n", GetCurrentThreadId(), waitTime, lastTime);
WriteFile(hFile, buf, strlen(buf), NULL, NULL);
CloseHandle(hFile);
ReleaseMutex(hMutexRW);
ReleaseMutex(hMutexW);
}
return 0;
}
int main()
{
HANDLE hFile;
hFile = CreateFile(TEXT("nice.txt"), GENERIC_READ, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
CloseHandle(hFile);
DWORD IDThread[nThreadWriting+ nThreadReading];
HANDLE hThread[nThreadWriting + nThreadReading];
int num[nThreadWriting + nThreadReading];
for (int i = 0; i < nThreadWriting + nThreadReading; i++)
num[i] = i;
hMutexRW = CreateMutex(NULL, FALSE, NULL);
hMutexR = CreateMutex(NULL, FALSE, NULL);
hMutexW = CreateMutex(NULL, FALSE, NULL);
hMutexN = CreateMutex(NULL, FALSE, NULL);
if (!hMutexRW || !hMutexW || !hMutexR)
return 1;
for (int i = 0; i < nThreadReading; i++)
{
hThread[i] = (HANDLE)_beginthreadex(NULL, 0, ThreadReading, num + i, 0, (unsigned int*)&IDThread[i]);
if (!hThread[i])
ExitProcess(3);
}
for (int i = nThreadReading; i < nThreadWriting + nThreadReading; i++)
{
hThread[i] = (HANDLE)_beginthreadex(NULL, 0, ThreadWriting, num + i, 0, (unsigned int*)&IDThread[i]);
if (!hThread[i])
ExitProcess(3);
}
WaitForMultipleObjects(nThreadWriting + nThreadReading, hThread, TRUE, INFINITE);
for (int i = 0; i < nThreadWriting + nThreadReading; i++)
CloseHandle(hThread[i]);
CloseHandle(hMutexRW);
CloseHandle(hMutexR);
CloseHandle(hMutexW);
CloseHandle(hMutexN);
return 0;
}