Re: Using getconf to set max_cmd_len

[Peter O'Gorman]

On Wed, 2007-05-30 at 15:58 -0700, Steve Ellcey wrote:
> While integrating a newer libtool into GCC, an issue arose with what
> value libtool was setting max_cmd_len to.  This patch uses 'getconf
> ARG_MAX' to set lt_cv_sys_max_cmd_len instead of going through a loop to
> try and divine the right value, this should give a more accurate value
> and should be faster too.  getconf is a Posix command that most
> platforms have and we drop into the old behaviour if it doesn't exist.
> 
> I originally thought about putting the getconf call before the case
> statement (thus skipping the special case handling if getconf exists),
> but then I thought it would be better to put the getconf usage into the
> generic case only so that people could still have special case targets
> if they wanted to avoid using getconf.  If the special case targets want
> to use getconf they can just delete their entry from the case statement
> and fall into the generic case.
> 
> Peter O'Gorman recommended using 3/4 of the value that getconf returned,
> so that is what I did.
> 
> I wasn't able to test this with the libtool test suite, I couldn't do a
> bootstrap and when I just did a "configure;make;make check" with the
> daily snapshot it didn't look like the new code was being used.
> 
> I did put the patch in my GCC tree and reconfigure and use it that way
> and verified that it worked in that context.  Most of the change is just
> indentation differences, there is really only a few new lines.

Looks good to me, I'll test it tonight and apply it to HEAD and
branch-1-5. I'll let you know if anything crops up that requires making
changes.

Thank you!

Peter