On 01/09/2012 03:42 PM, Peter Rosin wrote: > FWIW, this "fixes" it, but I don't actually know why a subshell would > make a difference? > > $ sh --version > GNU bash, version 3.1.17(1)-release (i686-pc-msys)
>
> -{
> +(
> (
> # Ignore common signals (in this subshell only!), to avoid potential
> # problems with Korn shells. Some Korn shells are known to propagate
> @@ -634,7 +634,7 @@ exit 0
> '
>
> # TODO: document that we consume the file descriptor 3 :-(
> -} 3>"$log_file"
> +) 3>"$log_file"
Ah - the classic bash bug documented in the autoconf manual:
https://www.gnu.org/software/autoconf/manual/autoconf.html#Limitations-of-Builtins
Bash 3.2 (and earlier versions) sometimes does not properly set ‘$?’
when failing to write redirected output of a compound command. This
problem is most commonly observed with ‘{...}’; it does not occur with
‘(...)’. For example:
$ bash -c '{ echo foo; } >/bad; echo $?'
bash: line 1: /bad: Permission denied
0
$ bash -c 'while :; do echo; done >/bad; echo $?'
bash: line 1: /bad: Permission denied
0
To work around the bug, prepend ‘:;’:
$ bash -c ':;{ echo foo; } >/bad; echo $?'
bash: line 1: /bad: Permission denied
1
--
Eric Blake ebl...@redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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