File descriptors

The total number of file descriptors has a hard limit of 32767 per process, but you're more likely to be constrained by the -F option to procnto or the RLIMIT_NOFILE system resource. The default value is 1000; the minimum is 100.

Note: Sockets, named semaphores, message queues, and connection IDs (coids) all use file descriptors.

To determine the current limit, use the ksh builtin command, ulimit, (see the Utilities Reference), or call getrlimit() (see the QNX Neutrino C Library Reference).