README-alpha

   1                          GNU libc SNAPSHOT SYSTEM
   2                             (general info)
   3                            Updated 1997-9-26
   4
   5 WHAT ARE GNU libc SNAPSHOTS
   6 ---------------------------
   7
   8 Snapshots are an "image" of the main glibc development tree, captured at a
   9 particular random instant in time.  When you use the snapshots, you should be
  10 able to maintain a local copy of libc that is no more than one day older than
  11 the official source tree used by the libc maintainers.
  12
  13 The primary purpose of providing snapshots is to widen the group of motivated
  14 developers that would like to help test, debug, and enhance glibc, by providing
  15 you with access to the "latest and greatest" source.  This has several
  16 advantages, and several disadvantages.
  17
  18     First the advantages:
  19
  20     o   Once we have a large base of motivated testers using the snapshots,
  21         this should provide good coverage across all currently supported
  22         glibc hosts and targets.  If a new bug is introduced in glibc due to
  23         fixing another bug or ongoing development, it should become
  24         obvious much more quickly and get fixed before the next general
  25         net release.  This should help to reduce the chances of glibc being
  26         released to the general public with a major bug that went unnoticed
  27         during the release cycle testing because they are machine dependent.
  28         We hope to greatly improve glibc's stability and reliability by
  29         involving more people and more execution environments in the
  30         prerelease testing.
  31
  32     o   With access to the latest source, any diffs that you send to fix
  33         bugs or add new features should be much easier for the glibc team
  34         to merge into the official source base (after suitable review
  35         of course).  This encourages us to merge your changes quicker,
  36         while they are still "fresh".
  37
  38     o   Once your diffs are merged, you can obtain a new copy of glibc
  39         containing your changes almost immediately.  Thus you do not
  40         have to maintain local copies of your changes for any longer
  41         than it takes to get them merged into the official source base.
  42         This encourages you to send in changes quicker.
  43
  44     And the disadvantages:
  45
  46     o   The snapshot you get will be largely untested and of unknown quality.
  47         It may fail to configure or compile.  It may have serious bugs.
  48         You should always keep a copy of the last known working version
  49         before updating to the current snapshot, or at least be able to
  50         regenerate a working version if the latest snapshot is unusable
  51         in your environment for some reason.
  52
  53         If a production version of glibc has a bug and a snapshot has the fix,
  54         and you care about stability, you should put only the fix for that
  55         particular problem into your production version.  Of course, if you
  56         are eager to test glibc, you can use the snapshot versions in your
  57         daily work, but users who have not been consulted about whether they
  58         feel like testing glibc should generally have something which is at
  59         least as bug free as the last released version.
  60
  61     o   Providing timely response to your questions, bug reports, and
  62         submitted patches will require the glibc development team to allocate
  63         time from an already thin time budget.  Please try to help us make
  64         this time as productive as possible.  See the section below about
  65         how to submit changes.
  66
  67
  68 WHO SHOULD TRY THE SNAPSHOTS
  69 ----------------------------
  70
  71 Remember, these are snapshots not tested versions.  So if you use
  72 these versions you should be able to
  73
  74     o   make sure your system stays usable
  75
  76     o   locate and hopefully fix problems
  77
  78     o   to port glibc to a new target yourself
  79
  80 You should not use the snapshots if
  81
  82     o   your system is needed in a production environment which needs
  83         stability
  84
  85     o   you expect us to fix your problems since you somehow depend on them.
  86         You must be willing to fix the problems yourself, we don't want to
  87         see "I have problems, fix this" messages.
  88
  89
  90 HOW TO GET THE SNAPSHOTS
  91 ------------------------
  92
  93 At the moment we provide a full snapshot weekly (every sunday), so
  94 that users getting a snapshot for the first time, or updating after
  95 a long period of not updating, can get the latest version in a single
  96 operation.  Along with the full snapshot, we will provide incremental
  97 diffs on a nearly daily basis (whenever code changes).  Each daily
  98 diff will be relative to the source tree after applying all previous
  99 daily diffs.  The daily diffs are for people who have relatively low
 100 bandwidth ftp or uucp connections.
 101
 102 The files will be available via anonymous ftp from alpha.gnu.org, in
 103 directory /gnu/libc and on linux.kernel.org in /pub/software/libs/glibc.  The
 104 directories should look something like:
 105
 106         libc-970921.tar.gz
 107         libc-970917-970922.diff.gz
 108         libc-970922-970925.diff.gz
 109         .
 110         .
 111         .
 112
 113 Please note that the snapshots on alpha.gnu.org and on
 114 linux.kernel.org are not always in sync. Patches to some files might
 115 appear a day a diff earlier or later on alpha than on kernel.
 116 Use always alpha or always kernel but don't mix them.
 117
 118 There are sometimes additionally test releases of the add-ons available in
 119 these directories.  If a new version of an add-on is available it is normally
 120 required for the corresponding snapshot so always pay attention for these.
 121
 122 Note that we provide GNU gzip compressed files only.  You can ftp gzip
 123 from ftp.gnu.org in directory pub/gnu.
 124
 125 In some cases the dates for diffs and snapshots do not match like in the
 126 example above.  The full release is for 970921 but the patch is for
 127 970917-970922.  This only means that nothing changed between 970917 and 970922
 128 and that you have to use this patch on top of the 970921 snapshot since the
 129 patch is made on 970922.
 130
 131 Also, as the gcc developers did with their gcc snapshot system, even though we
 132 will make the snapshots available on a publically accessible ftp area, we ask
 133 that recipients not widely publicise their availability.  The motivation for
 134 this request is not to hoard them, but to avoid the situation where the
 135 general glibc user base naively attempts to use the snapshots, has trouble with
 136 them, complains publically, and the reputation of glibc declines because of a
 137 perception of instability or lack of quality control.
 138
 139
 140 GLIBC TEST SUITE
 141 ----------------
 142
 143 A test suite is distributed as an integral part of the snapshots.  A simple
 144 "make check" in your build directory is sufficient to run the tests.  glibc
 145 should pass all tests and if any fails, please report it.  A failure might not
 146 originate from a bug in glibc but also from bugs in the tools, e.g. with gcc
 147 2.7.2.x the math tests fail some of the tests because of compiler bugs.
 148
 149 Note that the test suite is still in its infancy.  The tests themselves only
 150 cover a small portion of libc features, and where tests do exist for a feature
 151 they are not exhaustive.  New tests are welcome.
 152
 153
 154 GETTING HELP, GLIBC DISCUSSIONS, etc
 155 ------------------------------------
 156
 157 People who want to help with glibc and who test out snapshots regularly should
 158 get on the libc-alpha@cygnus.com mailing list by sending an email to
 159 libc-alpha-request@cygnus.com.  This list is meant (as the name suggests)
 160 for the discussion of test releases and also reports for them.  People who are
 161 on this list are welcome to post questions of general interest.
 162
 163 People who are not only willing to test the snapshots but instead really want
 164 to help developing glibc should contact libc-hacker-request@cygnus.com.org to
 165 be put on the developers mailing list.  This list is really only meant for
 166 developers.  No questions about installation problems or other simple topics
 167 are wanted nor will they be answered.
 168
 169 Do *not* send any questions about the snapshots or patches specific to the
 170 snapshots to bug-glibc@gnu.org.  Nobody there will have any idea what
 171 you are talking about and it will just cause confusion.
 172
 173
 174 BUG REPORTS
 175 -----------
 176
 177 Send bug reports directly to Ulrich Drepper <drepper@gnu.org>.  Please
 178 do *not* use the glibcbug script for reporting bugs in the snapshots.
 179 glibcbug should only be used for problems with the official released versions.
 180 We don't like bug reports in the bug database because otherwise the impression
 181 of instability or lack of quality control of glibc as a whole might manifest
 182 in people's mind.
 183
 184 Note that since no testing is done on the snapshots, and snapshots may even be
 185 made when glibc is in an inconsistent state, it may not be unusual for an
 186 occasional snapshot to have a very obvious bug, such as failure to compile on
 187 *any* machine.  It is likely that such bugs will be fixed by the next
 188 snapshot, so it really isn't necessary to report them unless they persist for
 189 a couple of days.
 190
 191 Missing files should always be reported, since they usually mean there is a
 192 problem with the snapshot-generating process and we won't know about them
 193 unless someone tells us.
 194
 195 Bugs which are non-obvious, such as failure to compile on only a specific
 196 machine, a new machine dependent or obscure bug (particularly one not detected
 197 by the testsuite), etc should be reported when you discover them, or have a
 198 suggested patch to fix them.
 199
 200
 201 FORMAT FOR PATCHES
 202 ------------------
 203
 204 If you have a fix for a bug, or an enhancement to submit, send your patch to
 205 Ulrich Drepper <drepper@gnu.org>.  Here are some simple guidelines for
 206 submitting patches:
 207
 208     o   Use "unified diffs" for patches.  A typical command for generating
 209         context diffs is "diff -ru glibc-old glibc-patched".
 210
 211     o   Use the "minimalist approach" for patches.  That is, each patch
 212         should address only one particular bug, new feature, etc.  Do not
 213         save up many unrelated changes and submit them all in one big
 214         patch, since in general, the larger the patch the more difficult
 215         it is for us to decide if the patch is either correct or
 216         desirable.  And if we find something about the patch that needs
 217         to be corrected before it can be installed, we would have to reject
 218         the entire patch, which might contain changes which otherwise would
 219         be accepted if submitted separately.
 220
 221     o   Submit a sample ChangeLog entry with your patch.  See the existing
 222         glibc ChangeLog for examples of what a ChangeLog entry should look
 223         like.  The emacs command ^X4A will create a ChangeLog entry header
 224         for you.
 225
 226
 227 BUILDING SNAPSHOTS
 228 ------------------
 229
 230 The `best' way to build glibc is to use an extra directory, e.g.:
 231 tar xzf libc-970921.tar.gz
 232 mkdir build-glibc
 233 cd build-glibc
 234 ../libc-970921/configure ...
 235
 236 In this way you can easily clean up (since `make clean' doesn't work at
 237 the moment) and rebuild glibc.
 238
 239
 240 NECESSARY TOOLS
 241 ---------------
 242
 243 For the recommended versions of gcc, binutils, make, texinfo, gettext,
 244 autoconf and other tools which might be especially needed when using patches,
 245 please read the file INSTALL.
 246
 247
 248 HOW CAN YOU HELP
 249 ----------------
 250
 251 It helps already a lot if you just install glibc on your system and try to
 252 solve any problems.  You might want to look at the file `PROJECTS' and help
 253 with one of those projects, fix some bugs (see `BUGS' or the bug database),
 254 port to an unsupported platform, ...
 255
 256
 257 FURTHER DOCUMENTATION
 258 ---------------------
 259
 260 A lot of questions are answered in the FAQ.  The files `INSTALL', `README' and
 261 `NOTES' contain the most important documentation.  Furthermore glibc has its
 262 own 700+ pages info documentation, ...
 263
 264
 265
 266 And finally a word of caution: The libc is one of the most fundamental parts
 267 of your system - and these snapshots are untested and come without any
 268 guarantee or warranty.  You might be lucky and everything works or you might
 269 crash your system.  If you install a glibc snapshot as primary library, you
 270 should have a backup somewhere.
 271
 272 On many systems it is also a problem to replace the libc while the system is
 273 running.  In the worst case on broken OSes some systems crash.  On better
 274 systems you can move the old libc aside but removing it will cause problems
 275 since there are still processes using this libc image and so you might have to
 276 check the filesystem to get rid of the libc data.  One good alternative (which
 277 is also safer) is to use a chroot'ed environment.
 278
 279 Thanks for your help and support.
 280
 281 Thanks to Fred Fish from Cygnus for the original version of this text
 282 (for GDB).
 283
 284
 285 Ulrich Drepper