CreateMutex replacment using pthread_mutex ?

Hello, I am developing a Qt application which needs to lock its critical data from accesing on different instances. Thus I implement the singleton concept and I needed more low-level way to create Mutex and lock the access of critical data.

For the QT_WS_WIN scope I use:

Code:

---

QT_WA(
   {m_hMutex=CreateMutex(0, FALSE, (TCHAR*)id().utf16());},
   {m_hMutex=CreateMutexA(0, FALSE, id().toLocal8Bit().data());}
  );
  switch(WaitForSingleObject(m_hMutex, INFINITE))
  {
  case WAIT_TIMEOUT:
   CloseHandle(m_hMutex);
   m_hMutex = 0;
   break;
  }

---

And for QT_WS_X11 I use:

Code:

---

pthread_mutex_t *mutex;
pthread_mutexattr_t *attr;
// initialize them with their _init methods

---

and then

Code:

---

pthread_mutex_lock(mutex);
// critical data
pthread_mutex_unlock(mutex);

---

Whatsoever, the result is not as expected. For Windows the above method works well, but using the posix way, with pthread_mutex, the locking is not done as it is supposed. I think it might be related to the way the Mutex for Win32 is identified within the QT_WA macro.

Any help for finding the best replacement would be appreciated.

thanks

Why not use QMutex or QSystemSemaphore depending on what you want?

Quote:

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Originally Posted by wysota

Why not use QMutex or QSystemSemaphore depending on what you want?

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because as far as I see there is no way to make the mutex on system level, it is only for the pid of the application.

Quote:

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Originally Posted by afail

because as far as I see there is no way to make the mutex on system level, it is only for the pid of the application.

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To quote the docs:

"Unlike QSemaphore, a QSystemSemaphore can also be accessed from multiple processes."

Quote:

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Originally Posted by Methedrine

To quote the docs:

"Unlike QSemaphore, a QSystemSemaphore can also be accessed from multiple processes."

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ahm.. what I used to read was Qt 4.4.3.
Is there some kind of workaround for Qt < 4.5 ?

Quote:

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Originally Posted by afail

ahm.. what I used to read was Qt 4.4.3.
Is there some kind of workaround for Qt < 4.5 ?

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To quote the docs again...

"This class was introduced in Qt 4.4."

Sorry to reopen this issue but the semaphore behaves a little bit strange.

If I start 2 processes one after another, all is fine and the lock is done correctly. If I start 10 processes one after another (i.e. in GNU/Linux: # ./exefile & ./exefile & ./exefile & ./exefile) then either some of the instances crashes or starts as separate instance (which shouldn't).

Any ideas?

Separate instance of what? What is exactly that you are trying to do and how are you trying to do it?