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#1 (**permalink**) 04-11-2008, 12:53 AM

I want to append switches to CXXFLAGS but not in CFLAGS. This:

append-flags "-fno-strict-aliasing -fno-rtti -fno-exceptions"

will append those switches to both CFLAGS as well as CXXFLAGS, which I
don't want. Any solution?

PS:
The first switch (-fno-strict-aliasing) is needed; the C++ part of the
program segfaults otherwise on some systems with -O2 and higher (not on
mine though, but I want to contribute the ebuild). It's safe with -O1
(even when using "-O1 -fstrict-aliasing); probably a compiler bug, not
sure. The C part of the program isn't affected so this switch isn't
needed in CFLAGS.

The other flags are just to "optimize" a bit; the package doesn't use
RTTI nor exceptions so I think it's a good idea to use those flags for a
slightly smaller runtime. Those flags are never in the global CXXFLAGS
since they simply break packages that do use RTTI and exceptions.

#2 (**permalink**) 04-11-2008, 12:53 AM

Nikos Chantziaras wrote:

> I want to append switches to CXXFLAGS but not in CFLAGS. This:
>
> append-flags "-fno-strict-aliasing -fno-rtti -fno-exceptions"
>
> will append those switches to both CFLAGS as well as CXXFLAGS, which I
> don't want. Any solution?

- if you want this for all the packages, set CXXFLAGS in /etc/make.conf
- if it's only for some packages, then put the flags
in /etc/portage/env/category/package or in /etc/portage/bashrc

Google for "gentoo per-package CFLAGS". See bug #44796 on bugs.gentoo.org.

#3 (**permalink**) 04-11-2008, 12:53 AM

pk <pk@pk.invalid> wrote:
> Nikos Chantziaras wrote:
>
>> I want to append switches to CXXFLAGS but not in CFLAGS. This:
>>
>> append-flags "-fno-strict-aliasing -fno-rtti -fno-exceptions"
>>
>> will append those switches to both CFLAGS as well as CXXFLAGS, which
>> I don't want. Any solution?
>
> - if you want this for all the packages, set CXXFLAGS in
> /etc/make.conf
> - if it's only for some packages, then put the flags
> in /etc/portage/env/category/package or in /etc/portage/bashrc
>
> Google for "gentoo per-package CFLAGS". See bug #44796 on
> bugs.gentoo.org.

He wants to know how to do this in an *ebuild* -- in other words a package
he can distribute, so that all clients who emerge that ebuild will get those
flags added.

--
*Art

#4 (**permalink**) 04-11-2008, 12:53 AM

Arthur Hagen wrote:

> He wants to know how to do this in an *ebuild* -- in other words a package
> he can distribute, so that all clients who emerge that ebuild will get
> those flags added.

Ah, well. Then the question is best discussed on the gentoo-dev mailing
linst, since it seems that the flag-o-matic eclass can't help in this case
(short of ugly tricks like saving CFLAGS, changing flags as needed, and
restoring CFLAGS with the saved value).

#5 (**permalink**) 04-11-2008, 12:53 AM

Nikos Chantziaras wrote:
> I want to append switches to CXXFLAGS but not in CFLAGS. This:
>
> append-flags "-fno-strict-aliasing -fno-rtti -fno-exceptions"
>
> will append those switches to both CFLAGS as well as CXXFLAGS, which I
> don't want. Any solution?

# X="abcde" ; echo $X ; X=$X"fghij" ; echo $X
abcde
abcdefghij

--
"Theoretically, there is nothing that can stop the government from taxing 100%
of income so long as the people get benefits from the government commensurate
with their income which is taxed." -- Barack Obama

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Appending switches to CXXFLAGS in an ebuild