dan.cantrell at xilinx
Sep 25, 1995, 8:44 PM
Post #1 of 4
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problem with signal handling
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Brief: Not processing SIGCHLD correctly.
Description: I have a program that will start child processes to do
stuff and exit. One or more of these child processes may be running at a
time. I want to do some things when a child exits. The first child to
exit is handled fine. But, the second and all later child signals are
not handled. I can reproduce this error with the included short script.
I am also including the output and config info for my environment.
I can get around this problem by reseting the $SIG{'CHLD'} right after the
wait().
Please let me know if this is a Perl5.001m bug, or if this is particular
to my build.
Thank you.
Dan Cantrell
dan.cantrell [at] xilinx
Script used to reproduce error:
-------------------
#! /opt/perl5/bin/perl
sub mkchld {
local( $pid );
$pid = fork();
if( $pid )
{
print "New: $pid\n";
push( @procs, $pid );
return;
}
sleep 5;
exit;
}
$SIG{'CHLD'} = 'reap';
sub reap {
local( $pid ) = wait;
print "Got: $pid\n";
return;
}
&mkchld;
sleep 10;
&mkchld;
sleep 10;
&mkchld;
sleep 10;
exit;
------------------
Output from script:
-----------------
New: 17033
Got: 17033
New: 17035
New: 17039
The output should have a 'Got' line for each 'New' line.
Process list on machine right before program exited:
-------------------
dan 17035 17032 2 0:00 <defunct>
dan 17039 17032 3 0:00 <defunct>
I have Perl5.001m, output of a -v:
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This is perl, version 5.001
Unofficial patchlevel 1m.
Copyright 1987-1994, Larry Wall
Perl may be copied only under the terms of either the Artistic License or
the
GNU General Public License, which may be found in the Perl 5.0 source kit.
output of myconfig:
-------------------
Summary of my perl5 (patchlevel 1) configuration:
Platform:
osname=solaris, osver=2.4, archname=sun4-solaris
uname='sunos cray 5.4 generic_101945-10 sun4m sparc '
hint=recommended
Compiler:
cc='cc', optimize='-O', ld='cc'
cppflags='-s'
ccflags ='-s'
ldflags =''
stdchar='unsigned char', d_stdstdio=define, usevfork=false
voidflags=15, castflags=0, d_casti32=define, d_castneg=define
intsize=4, alignbytes=8, usemymalloc=y, randbits=15
Libraries:
so=so
libpth=/lib /usr/lib /usr/ccs/lib /usr/local/lib
libs=-lsocket -lnsl -ldl -lm -lc -lcrypt
libc=
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef
cccdlflags='-Kpic', ccdlflags=' ', lddlflags='-G'
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