[Qt-interest] Using Semaphores multiple times in different instances of a class

[Jannis Achstetter]

Hello list,

I have an application in C++ that creates multiple instances of a class.
Every instance shall have its own circular buffer (used to store audio
samples decoded elsewhere in that instance). An instance of another
class then calls a function of every decoding-instance to get audio from
the instance's circular buffer.
As long there is only one audio stream (one instance of the decoding
class), everything is fine. As soon as two (ore more) audio streams are
working with "their" circular buffer, the data gets corrupted.
To manage the circular buffer, I use QSemaphores as shown in the
Semaphore Example (Qt Examples -> Threading). Since I do not want them
global but per-instance, I tried to "declare" the Semaphores in the
classes header-file as "private" variables. This did not work,
Semaphores do not behave like normal class instances (the compiler
throws an error concerning the numeral value in the braces).
So I declared them in the classes source-code. Since the Semaphores are
used by several functions of the class, I did not declare them in a
function itself but outside any function (making them global obiviosly).
When I try to use the scope ("QSemaphore ClassName::SemName(int)"), the
compiler throws an error.

So my question is: How can I implement a class where every instance has
its own copy of two QSemaphores? Or, if not possible: How do I implement
a class where every instance has its own circular buffer?

If anyone wants to see my source code to better understand my problem I
can host it on my server. Two classes + headers were just too much for a
mail to a list.

Best regards,
	Jannis