Question

It’s highly likely that there is a limitation on how many synchronization objects – semaphores, events, critical sections – can one process and all processes on a given machine use. What exactly is this limitation?

Answer 1

For windows, the per-process limit on kernel handles(semaphores, events,mutex) is 2^24.

From MSDN:

Kernel object handles are process
specific. That is, a process must
either create the object or open an
existing object to obtain a kernel
object handle. The per-process limit
on kernel handles is 2^24. However,
handles are stored in the paged pool,
so the actual number of handles you
can create is based on available
memory. The number of handles that you
can create on 32-bit Windows is
significantly lower than 2^24.