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naga jolokia
n00b
Joined: 28 Dec 2013
Posts: 10
Location: Berlin
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 Posted: Fri Feb 20, 2015 11:52 am Post subject: Documentation needed for some default USE flags |
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During installation following the handbook I kept the profile as | Code: | | [1] default/linux/amd64/13.0 * |
and didn't change any USE flags in /mnt/gentoo/etc/portage/make.conf nor somewhere else.
As the example in the handbook as well as
on my machine shows, there are some USE flags set by default, about that I can't find any description neither in /usr/portage/profiles/use.desc nor at the use index.
The flags in question are: amd64, cli, mmx, sse, sse2.
So my questions are:
Where can I find a comprehensive documentation including all USE flags?
Where are these flags set?
Is there a reason for not documenting them in the aforementioned sources?
Thanks in advance
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John R. Graham
Administrator
Joined: 08 Mar 2005
Posts: 10590
Location: Somewhere over Atlanta, Georgia
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| Posted: Fri Feb 20, 2015 12:09 pm Post subject: |
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To my knowledge, amd64 is not and never has been a USE flag. As for the others, they used to be USE flags proper but have been moved into their own namespace in the CPU_FLAGS_X86 variable. (They're still kind-of USE flags, though.) They mirror instruction set features that some (but not all) x86 CPUs have. Some packages have hand-coded assembler routines to take special advantages of those instructions if they're available, and those are the features that are enabled by the flags in CPU_FLAGS_X86. These used to be part of the regular USE variable (and described in the normal documentation). I'm afraid you've caught Gentoo in transition where the technical implementation has moved ahead of the documentation.
The main purpose of the profiles is to set default USE flags, keywords, and masks. In the absence of your settings in /etc/portage/, all USE flags you see set in the output of "emerge --info" come from the selected profile.
- John
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I can confirm that I have received between 0 and 499 National Security Letters. |
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Jaglover
Watchman
Joined: 29 May 2005
Posts: 8291
Location: Saint Amant, Acadiana
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desultory
Bodhisattva
Joined: 04 Nov 2005
Posts: 9410
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| Posted: Mon Feb 23, 2015 4:59 am Post subject: |
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| John R. Graham wrote: | | To my knowledge, amd64 is not and never has been a USE flag. |
It is slightly more confusing, at least on the surface, than that. It, along with all of the other architecture keywords appear in their unqualified forms as USE flags and are set by default on the architecture to which they correspond. However they should not appear in make.conf or package.use outside of rather exceptional circumstances such as when working on porting to new architectures; since they are, naturally, used to control applying patches (conditional patches in general are somewhat deprecated, though a relatively common practice) or enabling features that are thought to only work (or for whatever other reason are only allowed) on the corresponding architectures.
Moved from Documentation, Tips & Tricks to Other Things Gentoo. |
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