Re: [PATCH] Change configure to check if pthreads are usable without any extra flags

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 9, 2012, 17:44 UTC
Message-ID: <7vy5mskewg.fsf@alter.siamese.dyndns.org>
In-Reply-To: <C56B4151-8912-4B3A-8A97-E769A878AE68@quendi.de>

Max Horn <max@quendi.de> writes:

Show 15 quoted lines

>>> diff --git a/configure.ac b/configure.ac
>>> index 4e9012f..d767ef3 100644
>>> --- a/configure.ac
>>> +++ b/configure.ac
>>> @@ -1002,7 +1002,7 @@ if test -n "$USER_NOPTHREAD"; then
>>> # -D_REENTRANT' or some such.
>>> elif test -z "$PTHREAD_CFLAGS"; then
>>>   threads_found=no
>>> -  for opt in -mt -pthread -lpthread; do
>>> +  for opt in "" -mt -pthread -lpthread; do
>> 
>> Hmph.  Would it work to append the new empty string at the end of
>> the existing list, as opposed to prepending it?
>
> No, because that loop aborts on the first match that "works". Since no flags are necessary on OS X, but adding "-mt" to the flags "works" in the sense that it does nothing (except triggering a warning about an unknown argument), we need to check the empty string before "-mt" that.

If the test in that "for opt ...; do" considers the linking "work", why do you even want to tweak it, and instead let "-mt" be passed?

If the warning troubles you, would it be feasible for the purpose of the check to tweak the definition of "works" used in the loop so that it considers the warning as "not working"?