* Precompiled headers issue: -c and -fpch-preprocess should be used together?
@ 2010-03-29 7:57 Pavel Shevaev
2010-04-07 14:36 ` Ian Lance Taylor
0 siblings, 1 reply; 5+ messages in thread
From: Pavel Shevaev @ 2010-03-29 7:57 UTC (permalink / raw)
To: gcc-help
Folks, I'm using gcc-4.4.1(4.4.1-4ubuntu9 to be precise) on Ubuntu and
after trying to make PCH work properly for some time I found that
precompiled headers are not used if -c option used. Experimenting with
different options I discovered that it's the -fpch-preprocess option
which enables PCH in this case.
Is it an expected behavior? If yes, maybe it should be documented here
http://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html in order to
save some time for others :)
--
Best regards, Pavel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Precompiled headers issue: -c and -fpch-preprocess should be used together?
2010-03-29 7:57 Precompiled headers issue: -c and -fpch-preprocess should be used together? Pavel Shevaev
@ 2010-04-07 14:36 ` Ian Lance Taylor
2010-04-16 20:59 ` Pavel Shevaev
0 siblings, 1 reply; 5+ messages in thread
From: Ian Lance Taylor @ 2010-04-07 14:36 UTC (permalink / raw)
To: Pavel Shevaev; +Cc: gcc-help
Pavel Shevaev <pacha.shevaev@gmail.com> writes:
> Folks, I'm using gcc-4.4.1(4.4.1-4ubuntu9 to be precise) on Ubuntu and
> after trying to make PCH work properly for some time I found that
> precompiled headers are not used if -c option used. Experimenting with
> different options I discovered that it's the -fpch-preprocess option
> which enables PCH in this case.
>
> Is it an expected behavior? If yes, maybe it should be documented here
> http://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html in order to
> save some time for others :)
It is very likely that you are using ccache or distcc. Those tools
first preprocess the C source code and then compile it. It's true
that if you are preprocessing, you need to use the -fpch-preprocess
option. However, -fpch-preprocess is not required if you do not
preprocess, and omitting it should work fine when using gcc proper
rathre than ccache or distcc.
Ian
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Precompiled headers issue: -c and -fpch-preprocess should be used together?
2010-04-07 14:36 ` Ian Lance Taylor
@ 2010-04-16 20:59 ` Pavel Shevaev
2010-04-17 3:23 ` Ian Lance Taylor
0 siblings, 1 reply; 5+ messages in thread
From: Pavel Shevaev @ 2010-04-16 20:59 UTC (permalink / raw)
To: Ian Lance Taylor; +Cc: gcc-help
> It is very likely that you are using ccache or distcc.
You are absolutely correct, I'm using both ccache and distcc.
> Those tools
> first preprocess the C source code and then compile it. It's true
> that if you are preprocessing, you need to use the -fpch-preprocess
> option. However, -fpch-preprocess is not required if you do not
> preprocess, and omitting it should work fine when using gcc proper
> rathre than ccache or distcc.
Thanks for the explanation! I just wonder why not putting this info on
the pch help page somewhere?
--
Best regards, Pavel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Precompiled headers issue: -c and -fpch-preprocess should be used together?
2010-04-16 20:59 ` Pavel Shevaev
@ 2010-04-17 3:23 ` Ian Lance Taylor
2010-04-19 17:51 ` Pavel Shevaev
0 siblings, 1 reply; 5+ messages in thread
From: Ian Lance Taylor @ 2010-04-17 3:23 UTC (permalink / raw)
To: Pavel Shevaev; +Cc: gcc-help
Pavel Shevaev <pacha.shevaev@gmail.com> writes:
>> Those tools
>> first preprocess the C source code and then compile it. It's true
>> that if you are preprocessing, you need to use the -fpch-preprocess
>> option. However, -fpch-preprocess is not required if you do not
>> preprocess, and omitting it should work fine when using gcc proper
>> rathre than ccache or distcc.
>
> Thanks for the explanation! I just wonder why not putting this info on
> the pch help page somewhere?
It's kind of special purpose and I think it would fit better on
http://gcc.gnu.org/wiki/FAQ . Want to add an entry?
Ian
^ permalink raw reply [flat|nested] 5+ messages in thread
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2010-03-29 7:57 Precompiled headers issue: -c and -fpch-preprocess should be used together? Pavel Shevaev
2010-04-07 14:36 ` Ian Lance Taylor
2010-04-16 20:59 ` Pavel Shevaev
2010-04-17 3:23 ` Ian Lance Taylor
2010-04-19 17:51 ` Pavel Shevaev
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