Mail Archives: cygwin/2007/12/21/10:39:13
test.pl:
----
$childpid=fork;
die "failed to fork" if (!defined $childpid);
if (! $childpid) {
close STDIN;
close STDOUT;
close STDERR;
exec "make -f test.mk &>test.out";
}
----
test.mk:
----
var=$(shell echo foobar | cat)
default:
@echo "$(var)"
----
Running "make -f test.mk" from a terminal works as expected -- "foobar" is
echoed. Running test.pl, however, causes the sh.exe process to hang
apparently indefinitely -- the first time I observed this was in an
overnight cronjob, and `sh -c "echo xml4csrc2_2_0 |tr 'a-z' 'A-Z'"` had
been running for approximately 11 hours.
The trigger appears to be the combination of make, the pipeline appearing
in the shell command, and not being attached to a terminal. If I remove
any of these factors (by removing the '| cat', changing 'make -f test.mk'
into 'sh -c "echo foo | cat"', or running "make -f test.mk" from a
terminal), the problem does not manifest itself and everything behaves as
expected. I've so far managed to reproduce the problem on three different
machines with versions 3.1.17 and 3.2.25 of bash, and versions 1.5.24-2
and 1.5.25-7 of the cygwin DLL.
Any suggestions?
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