process_forking_in_nspr.rst

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Process forking in NSPR

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The threads provided in NetScape Portable Runtime (NSPR) are implemented

using different mechanisms on the various platforms. On some platforms,

NSPR threads directly map one-to-one to the threads provided by the

platform vendor, on other platforms NSPR threads are basically

user-level threads within a single process (with no kernel threads) and

on still others NSPR threads are user-level threads implemented on top

of one or more kernel threads within single address space.

NSPR does not override the fork function and so, when fork is called

from the NSPR thread the results are different on the various platforms.

All the threads present in the parent process may be replicated in the

child process, only the calling thread may be replicated in the child

process or only the calling kernel thread may be replicated.

So, to be consistent across all platforms, it is suggested that when

using fork in a NSPR thread;

#. The exec function should be called in the child process.

#. No NSPR functions should be called in the child process before the

   exec call is made.