286 lines
12 KiB
Plaintext
286 lines
12 KiB
Plaintext
GNU libc SNAPSHOT SYSTEM
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(general info)
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Updated 1997-9-26
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WHAT ARE GNU libc SNAPSHOTS
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---------------------------
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Snapshots are an "image" of the main glibc development tree, captured at a
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particular random instant in time. When you use the snapshots, you should be
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able to maintain a local copy of libc that is no more than one day older than
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the official source tree used by the libc maintainers.
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The primary purpose of providing snapshots is to widen the group of motivated
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developers that would like to help test, debug, and enhance glibc, by providing
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you with access to the "latest and greatest" source. This has several
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advantages, and several disadvantages.
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First the advantages:
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o Once we have a large base of motivated testers using the snapshots,
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this should provide good coverage across all currently supported
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glibc hosts and targets. If a new bug is introduced in glibc due to
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fixing another bug or ongoing development, it should become
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obvious much more quickly and get fixed before the next general
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net release. This should help to reduce the chances of glibc being
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released to the general public with a major bug that went unnoticed
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during the release cycle testing because they are machine dependent.
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We hope to greatly improve glibc's stability and reliability by
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involving more people and more execution environments in the
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prerelease testing.
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o With access to the latest source, any diffs that you send to fix
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bugs or add new features should be much easier for the glibc team
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to merge into the official source base (after suitable review
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of course). This encourages us to merge your changes quicker,
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while they are still "fresh".
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o Once your diffs are merged, you can obtain a new copy of glibc
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containing your changes almost immediately. Thus you do not
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have to maintain local copies of your changes for any longer
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than it takes to get them merged into the official source base.
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This encourages you to send in changes quicker.
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And the disadvantages:
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o The snapshot you get will be largely untested and of unknown quality.
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It may fail to configure or compile. It may have serious bugs.
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You should always keep a copy of the last known working version
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before updating to the current snapshot, or at least be able to
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regenerate a working version if the latest snapshot is unusable
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in your environment for some reason.
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If a production version of glibc has a bug and a snapshot has the fix,
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and you care about stability, you should put only the fix for that
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particular problem into your production version. Of course, if you
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are eager to test glibc, you can use the snapshot versions in your
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daily work, but users who have not been consulted about whether they
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feel like testing glibc should generally have something which is at
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least as bug free as the last released version.
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o Providing timely response to your questions, bug reports, and
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submitted patches will require the glibc development team to allocate
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time from an already thin time budget. Please try to help us make
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this time as productive as possible. See the section below about
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how to submit changes.
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WHO SHOULD TRY THE SNAPSHOTS
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----------------------------
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Remember, these are snapshots not tested versions. So if you use
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these versions you should be able to
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o make sure your system stays usable
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o locate and hopefully fix problems
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o to port glibc to a new target yourself
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You should not use the snapshots if
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o your system is needed in a production environment which needs
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stability
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o you expect us to fix your problems since you somehow depend on them.
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You must be willing to fix the problems yourself, we don't want to
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see "I have problems, fix this" messages.
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HOW TO GET THE SNAPSHOTS
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------------------------
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At the moment we provide a full snapshot weekly (every sunday), so
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that users getting a snapshot for the first time, or updating after
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a long period of not updating, can get the latest version in a single
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operation. Along with the full snapshot, we will provide incremental
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diffs on a nearly daily basis (whenever code changes). Each daily
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diff will be relative to the source tree after applying all previous
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daily diffs. The daily diffs are for people who have relatively low
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bandwidth ftp or uucp connections.
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The files will be available via anonymous ftp from alpha.gnu.org, in
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directory /gnu/libc and on linux.kernel.org in /pub/software/libs/glibc. The
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directories should look something like:
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libc-970921.tar.gz
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libc-970917-970922.diff.gz
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libc-970922-970925.diff.gz
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.
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.
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.
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Please note that the snapshots on alpha.gnu.org and on
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linux.kernel.org are not always in sync. Patches to some files might
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appear a day a diff earlier or later on alpha than on kernel.
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Use always alpha or always kernel but don't mix them.
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There are sometimes additionally test releases of the add-ons available in
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these directories. If a new version of an add-on is available it is normally
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required for the corresponding snapshot so always pay attention for these.
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Note that we provide GNU gzip compressed files only. You can ftp gzip
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from ftp.gnu.org in directory pub/gnu.
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In some cases the dates for diffs and snapshots do not match like in the
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example above. The full release is for 970921 but the patch is for
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970917-970922. This only means that nothing changed between 970917 and 970922
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and that you have to use this patch on top of the 970921 snapshot since the
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patch is made on 970922.
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Also, as the gcc developers did with their gcc snapshot system, even though we
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will make the snapshots available on a publically accessible ftp area, we ask
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that recipients not widely publicise their availability. The motivation for
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this request is not to hoard them, but to avoid the situation where the
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general glibc user base naively attempts to use the snapshots, has trouble with
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them, complains publically, and the reputation of glibc declines because of a
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perception of instability or lack of quality control.
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GLIBC TEST SUITE
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----------------
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A test suite is distributed as an integral part of the snapshots. A simple
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"make check" in your build directory is sufficient to run the tests. glibc
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should pass all tests and if any fails, please report it. A failure might not
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originate from a bug in glibc but also from bugs in the tools, e.g. with gcc
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2.7.2.x the math tests fail some of the tests because of compiler bugs.
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Note that the test suite is still in its infancy. The tests themselves only
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cover a small portion of libc features, and where tests do exist for a feature
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they are not exhaustive. New tests are welcome.
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GETTING HELP, GLIBC DISCUSSIONS, etc
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------------------------------------
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People who want to help with glibc and who test out snapshots regularly should
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get on the libc-alpha@gnu.org mailing list by sending an email to
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libc-alpha-request@gnu.org. This list is meant (as the name suggests)
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for the discussion of test releases and also reports for them. People who are
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on this list are welcome to post questions of general interest.
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People who are not only willing to test the snapshots but instead really want
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to help developing glibc should contact libc-hacker-request@gnu.org to
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be put on the developers mailing list. This list is really only meant for
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developers. No questions about installation problems or other simple topics
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are wanted nor will they be answered.
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Do *not* send any questions about the snapshots or patches specific to the
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snapshots to bug-glibc@gnu.org. Nobody there will have any idea what
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you are talking about and it will just cause confusion.
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BUG REPORTS
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-----------
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Send bug reports directly to Ulrich Drepper <drepper@gnu.org>. Please
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do *not* use the glibcbug script for reporting bugs in the snapshots.
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glibcbug should only be used for problems with the official released versions.
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We don't like bug reports in the bug database because otherwise the impression
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of instability or lack of quality control of glibc as a whole might manifest
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in people's mind.
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Note that since no testing is done on the snapshots, and snapshots may even be
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made when glibc is in an inconsistent state, it may not be unusual for an
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occasional snapshot to have a very obvious bug, such as failure to compile on
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*any* machine. It is likely that such bugs will be fixed by the next
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snapshot, so it really isn't necessary to report them unless they persist for
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a couple of days.
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Missing files should always be reported, since they usually mean there is a
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problem with the snapshot-generating process and we won't know about them
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unless someone tells us.
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Bugs which are non-obvious, such as failure to compile on only a specific
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machine, a new machine dependent or obscure bug (particularly one not detected
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by the testsuite), etc should be reported when you discover them, or have a
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suggested patch to fix them.
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FORMAT FOR PATCHES
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------------------
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If you have a fix for a bug, or an enhancement to submit, send your patch to
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Ulrich Drepper <drepper@gnu.org>. Here are some simple guidelines for
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submitting patches:
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o Use "unified diffs" for patches. A typical command for generating
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context diffs is "diff -ru glibc-old glibc-patched".
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o Use the "minimalist approach" for patches. That is, each patch
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should address only one particular bug, new feature, etc. Do not
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save up many unrelated changes and submit them all in one big
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patch, since in general, the larger the patch the more difficult
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it is for us to decide if the patch is either correct or
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desirable. And if we find something about the patch that needs
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to be corrected before it can be installed, we would have to reject
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the entire patch, which might contain changes which otherwise would
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be accepted if submitted separately.
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o Submit a sample ChangeLog entry with your patch. See the existing
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glibc ChangeLog for examples of what a ChangeLog entry should look
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like. The emacs command ^X4A will create a ChangeLog entry header
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for you.
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BUILDING SNAPSHOTS
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------------------
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The `best' way to build glibc is to use an extra directory, e.g.:
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tar xzf libc-970921.tar.gz
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mkdir build-glibc
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cd build-glibc
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../libc-970921/configure ...
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In this way you can easily clean up (since `make clean' doesn't work at
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the moment) and rebuild glibc.
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NECESSARY TOOLS
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---------------
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For the recommended versions of gcc, binutils, make, texinfo, gettext,
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autoconf and other tools which might be especially needed when using patches,
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please read the file INSTALL.
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HOW CAN YOU HELP
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----------------
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It helps already a lot if you just install glibc on your system and try to
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solve any problems. You might want to look at the file `PROJECTS' and help
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with one of those projects, fix some bugs (see `BUGS' or the bug database),
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port to an unsupported platform, ...
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FURTHER DOCUMENTATION
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---------------------
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A lot of questions are answered in the FAQ. The files `INSTALL', `README' and
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`NOTES' contain the most important documentation. Furthermore glibc has its
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own 700+ pages info documentation, ...
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And finally a word of caution: The libc is one of the most fundamental parts
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of your system - and these snapshots are untested and come without any
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guarantee or warranty. You might be lucky and everything works or you might
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crash your system. If you install a glibc snapshot as primary library, you
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should have a backup somewhere.
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On many systems it is also a problem to replace the libc while the system is
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running. In the worst case on broken OSes some systems crash. On better
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systems you can move the old libc aside but removing it will cause problems
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since there are still processes using this libc image and so you might have to
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check the filesystem to get rid of the libc data. One good alternative (which
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is also safer) is to use a chroot'ed environment.
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Thanks for your help and support.
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Thanks to Fred Fish from Cygnus for the original version of this text
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(for GDB).
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Ulrich Drepper
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