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change cflags and chost later?
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mehlkelm
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Joined: 02 Sep 2005
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PostPosted: Fri Sep 02, 2005 3:47 pm    Post subject: change cflags and chost later? Reply with quote

I am right now doing my first gentoo install (stage 1).

i ended up with following make.conf and startet bootstrapping and am right now in the middle of emerge --emptytree system

make.conf:

USE="gnome gtk alsa -qt -kde cdr dvd"
CFLAGS="-O2 -march=pentium4"
CHOST="i386-pc-linux-gnu"
CXXFLAGS="${CFLAGS}"

I realized that since i am using a pentium 4 i should better have made the chost i686. Now my question is: is this bad (=wont work) or just not so good?
Another question is: Can I change the chost (or cflags) later? will that improve the apps i install afterwards?

thanks

stefan
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kimchi_sg
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Joined: 26 Nov 2004
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PostPosted: Fri Sep 02, 2005 4:00 pm    Post subject: Reply with quote

You can change CFLAGS anytime you want. Whether it will improve application performance is another story and depends very much on what you change it to, and what application you're thinking of.

CHOST is another kettle of fish. If you change it, you'll have to bootstrap and "emerge -e system" all over again, otherwise the system will not be able to find the C/C++ compiler.
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mehlkelm
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PostPosted: Fri Sep 02, 2005 4:45 pm    Post subject: Reply with quote

thank you.

would you recommed doing it again with the i686? is it worth it?
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kimchi_sg
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PostPosted: Sat Sep 03, 2005 12:42 am    Post subject: Reply with quote

mehlkelm wrote:
thank you.

would you recommed doing it again with the i686? is it worth it?

Yes, if you want to speed up your system by enabling NPTL (native posix threads library).
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doro1211
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PostPosted: Sat Sep 03, 2005 2:59 am    Post subject: Reply with quote

i686 is completely backwards compatible with i386. If you compile for i386, it will work on anything newer, but it won't be quite as fast. i686 allows the compiler to take advantage of certain instructions/optimizations that are present in the later processors but not the earlier ones. Something built for i686 won't work on an i386.
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Maedhros
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PostPosted: Sat Sep 03, 2005 7:23 am    Post subject: Reply with quote

Please see Changing CHOST Safe?

Moved from Installing Gentoo to Duplicate Threads.
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