fork() stops application 2

[Holger Vogt <holger dot vogt at uni-duisburg dot de>]

Hi,

another problem with fork to report:

I am compiling MAGIC under CYGWIN. MAGIC forks off a helper process
after establishing two pipes to comunicate with it. This "helper"
process is the way to ensure that X11 is able to run its event-driven
protocol (through calls to XNextEvent) while MAGIC runs its
interrupt-driven protocol (through calls to select()).  Both are
infinite (blocking) loops and must execute in parallel.

On Win98 this fork() takes a few ten seconds, on NT4 it is faster.

Later a second fork is required, e.g. for calling less to show help
information or for calling a simulator process. Again firstly there are
two pipes created, then fork() is called. This fork() call hangs up
MAGIC on Windows98, the whole OS freezes for a few minutes. All memory
seems to be used up, swapping to hard disk occurs. Later this blocking
disappers, but MAGIC still hangs. Under NT4 freezing and swapping occurs
during a shorter period, later on MAGIC continues.

Reading http://sources.redhat.com/ml/cygwin/2001-06/msg00256.html I
tried cygwin1-20010619.dll.  The kk test case now is o.k. (only tested
on Win98), also the first MAGIC fork is faster. The second freezes
however is still there.

I will try to create another test case, but maybe there is already some
info available.

Btw xterm (in xwin) crashes on cygwin1-20010619.dll.


Holger Vogt


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