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Re: [PATCH 09/12] use a shell function for AC_CHECK_TYPE


From: Eric Blake
Subject: Re: [PATCH 09/12] use a shell function for AC_CHECK_TYPE
Date: Sat, 01 Nov 2008 10:51:58 -0600
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According to Eric Blake on 10/27/2008 8:18 AM:
> Not for this patch, but food for thought for a subsequent improvement.  We 
> are 
> spending quite a few forks building two different test files; it should be 
> possible to build a single test file that does:
> 
> if (sizeof ($[]2))
>   return 0;
> #ifdef AC_SECOND
> if (sizeof (($[]2)))
>   return 0;
> #endif
> 
> then invoke the compiler with -DAC_SECOND added to CFLAGS on the second run, 
> to 
> reduce the overhead inherent in two full-blown AC_COMPILE_IFELSE.  I don't 
> think we can skip two separate compile runs, however, as I don't think we'll 
> be 
> lucky enough to accurately parse error messages to the point where we verify 
> that the compiler only complained about the second statement.

What do you think of this patch?  It doesn't reduce the size of configure
much (now that a single shell function body is the only place where this
is expanded), but does remove two cat processes.  On the other hand, it
adds an rm process, so I only see a net drop of one process per type
check.  Maybe we can still figure out a slicker way to reduce the number
of rm processes.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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