Thank you for your explanation. Since threads are still at "dev"-status (and btw slow on creation in perl), I'll switch to forking processes. Those hopefully work the same on different kernels/implementations. Do they?
You mentioned that memory is beeing shared when using threads. I could sucessfully change shared memory data as a non-superuser (with this threads-behaviour). But if you now use IPC::Shareable, you are able to set permissions for the shared memory between processes. Is the sharing between processes or threads on the same level (on Linux)? So you possibly could change permissions for thread shared memory as well? I'm just curious about shared memory, because it seems to me to be a good IPC tool.