Marcin Pawlik <[EMAIL PROTECTED]> writes:
> On Mon, Mar 24 at 10:33, Dominik Vogt wrote:
> > On Sun, Mar 23, 2003 at 06:30:32PM -0800, Elliot Sowadsky wrote:
> >>
> >> 2.5.6 on solaris 5.8
> >>
> >> piperead example in faq gives shell syntax error
> >>
> >> AddToFunc CenterWindow
> >> + I ThisWindow Piperead "echo Move \
> >> $(( $[vp.width]/2-$[w.width]/2 ))p \
> >> $(( $[vp.height]/2-$[w.height]/2 ))p"
> >>
> >> sh complains about missing (
> >>
> >> Actually i'm trying to calculate which horizontal pager window i'm in
> >> when i click on it.
> >
> > Look like the solaris /bin/sh does not know the "$(( ... ))" syntax.
>
> Checked in 5.9 and it really doesn't.
>
> > What is the most portable syntax for arithmetic expansion?
>
> Probably using (external) expr, but AFAIR the $(( )) arithmetic
> expansion should be supported in all POSIX compliant shells.
I checked, that notation is part of the POSIX requirement for shells.
This is what the Solaris 8 man page says about popen (what PipeRead uses):
popen:
The environment of the executed command will be as if a
child process were created within the popen() call using
fork(2). If the application is standard-conforming (see
standards(5)), the child is invoked with the call:
execl("/usr/bin/ksh", "ksh", "-c", command, (char *)0);
otherwise, the child is invoked with the call:
execl("/usr/bin/sh", "sh", "-c", command, (char *)0);
So, our man page statement about PipeRead using /bin/sh is not
strictly true on Solaris.
I built fvwm with gcc and arithmetic in PipeRead appears to work
for me.
The standards(5) man page is a bit confusing, but I think it
says you should use c89 instead of cc or define
_POSIX_C_SOURCE=199506L
when using Sun's compiler.
--
Dan Espen E-mail: [EMAIL PROTECTED]
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