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Date: Sun, 04 Aug 2019 18:52:30 +0200
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From: Houder <houder@xs4all.nl>
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Subject: Re: Regression (last snapshot)
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On Fri, 2 Aug 2019 14:34:02, Ken Brown  wrote:

> I think I've finally got it.
> 
> First of all, here's what POSIX says about signal handlers after an exec:
> 
> "Signals set to the default action (SIG_DFL) in the calling process 
> image shall be set to the default action in the new process image. 
> Except for SIGCHLD, signals set to be ignored (SIG_IGN) by the calling 
> process image shall be set to be ignored by the new process image. 
> Signals set to be caught by the calling process image shall be set to 
> the default action in the new process image (see <signal.h>)."
> 
> Second, here's a quote from the GTK+ documentation for gtk_init():
> 
> "Since 2.18, GTK+ calls signal (SIGPIPE, SIG_IGN) during initialization, 
> to ignore SIGPIPE signals, since these are almost never wanted in 
> graphical applications. If you do need to handle SIGPIPE for some 
> reason, reset the handler after gtk_init(), but notice that other 
> libraries (e.g. libdbus or gvfs) might do similar things."
> 
> Third, xwin-xdg-menu calls gtk_init() near the beginning of main().
> 
> Putting this all together, Eric's explanation is indeed correct.  All 
> processes created by xwin-xdg-menu via fork/exec inherit the property of 
> ignoring SIGPIPE.
> 
> I don't know if this is a bug, but it certainly leads to surprising 
> behavior.  Jon, maybe xwin-xdg-menu needs to call signal(SIGPIPE, 
> SIG_DFL) either after calling gtk_init() or before calling exec()?

Another option?

 - https://bugs.python.org/issue1652 - see msg115364 (Author: Mitar)

# GHC Haskell compiler is currently opting for a different solution:
#  installing an default empty handler which is cleared by exec
#  automatically and signal handler is restored back to SIG_DFL:
# 
# http://hackage.haskell.org/trac/ghc/ticket/4274

Installing the empty handler after the call to gtk_init() ...

Henri


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