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QProcess crashes

  • I'm trying to verify if the process is already running, if it's running closes and creates a new process.

    @QProcess *MyProcess;@

    @ if(MyProcess!= NULL)

    MyProcess = new QProcess(this);@

    My application crashes!

  • Just because the pointer "MyProcess" is not NULL, doesn't mean it's a valid pointer!

    It might be a dangling pointer, i.e. a pointer to an object that has already been deleted/destroyed.

    Any attempt to dereference a dangling pointer will result in undefined behavior (crash).

  • Moderators

    Besides the fact that you don't actually initialize MyProcess variable to NULL (maybe in your code you do) it's not the way to check if process is running. there is a method state() that returns current state of the process - not running, running or starting.

  • Even if the checking process status he continues crashing

    @ if(MyProcess->state() == QProcess::Running)


  • You still are dereferencing the "MyProcess" pointer. But is that pointer valid at all ???

    I mean: Do you assign the address of a QProcess object to that pointer before you try to dereference?

    Also, as said before, you also have problem if the object has already been deleted/destroyed...

    (If you get a crash on pointer access, it's almost always either a NULL pointer or a dangling pointer!)

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