Re: [PATCH - ping] Don't unlink /dev/null on darwin

[Peter O'Gorman <peter at pogma dot com>]

Zack Weinberg wrote:
> "Peter O'Gorman" <peter@pogma.com> writes:
> > Is there any reason this test for
> > -fvisibility=hidden can't go into a configure.ac somewhere? If not,
> > I'll look at making a patch to do so.
>
>
> It can't go in gcc/configure.ac because it is probing a property of
> the just-built compiler.

Yeah, okay, I see.

> Hopefully, libgcc will be split out to its own directory in the 4.1
> cycle, and will grow its own configure.ac.  The check can then go in
> there and will not need to use -o /dev/null. 

Can you please tell me, because I just don't understand it, how come having 
a temp file in the build dir will break parallel builds, but running a whole 
configure script won't.

Anyway, although I'm sure Geoffrey will pop in on this thread at some point 
and say "shut up already, I fixed as", I feel I must get rid of that -o 
/dev/null and need to find a way to do so that you agree with :)

I ran your patch by the way, and still lost /dev/null (hey, at least mine 
worked!), I guess that MAKECMDGOALS was not being set properly in the 
calling Makefile.

You seem to be worried about parallel recursive builds, I don't think your 
scenario is actually possible, however, would putting a $$ into the output 
file name make you less nervous? The temporary file should always be going 
into the builddir, I am about to run a test with a non-writable source dir 
to verify that that is true.

Here are some other possibilities, warning, many of these, on there own 
might induce vomiting, taken all together at once might require hospitalization.

1) $gcc_compile -v -help | grep '\-fvisibility=.*hidden'

2) Have a wrapper binary that calls tempnam() or something to specify the 
output file and do the test.

3) Have a gcc option to check for valid flags without creating any output 
(or requiring input).

4) You already suggested this, never run as root.


> If you're interested in
> helping with this, talk to Paolo Bonzini (cc:ed).

I am not averse to helping on things, but I don't really know my way around 
here that well, I'd likely be more of a hindrance than a help.

Peter
--
Peter O'Gorman - http://www.pogma.com