git 1.6.6.1 on glibc 2.2

git 1.6.6.1 on glibc 2.2

[Gabor Z. Papp]

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Hello all,

trying to compile git 1.6.6.1 on Linux 2.4.37.7, glibc 2.2.5:

read-cache.c: In function 'fill_stat_cache_info':
read-cache.c:72: error: 'struct stat' has no member named 'st_ctim'
read-cache.c:73: error: 'struct stat' has no member named 'st_mtim'
read-cache.c: In function 'read_index_from':
read-cache.c:1316: error: 'struct stat' has no member named 'st_mtim'
read-cache.c: In function 'write_index':
read-cache.c:1581: error: 'struct stat' has no member named 'st_mtim'
make: *** [read-cache.o] Error 1


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GIT_VERSION = 1.6.6.1
    * new build flags or prefix
    CC fast-import.o
    CC abspath.o
    CC advice.o
    CC alias.o
    CC alloc.o
    CC archive.o
    CC archive-tar.o
    CC archive-zip.o
    CC attr.o
    CC base85.o
    CC bisect.o
bisect.c: In function 'bisect_next_all':
bisect.c:869: warning: dereferencing pointer '__u' does break strict-aliasing rules
bisect.c:869: note: initialized from here
    CC blob.o
    CC branch.o
    CC bundle.o
bundle.c: In function 'verify_bundle':
bundle.c:125: warning: dereferencing pointer '__u' does break strict-aliasing rules
bundle.c:125: note: initialized from here
    CC cache-tree.o
    CC color.o
    CC combine-diff.o
combine-diff.c: In function 'show_patch_diff':
combine-diff.c:223: warning: dereferencing pointer '__u' does break strict-aliasing rules
combine-diff.c:223: note: initialized from here
    CC commit.o
    CC config.o
    CC connect.o
    CC convert.o
convert.c: In function 'apply_filter':
convert.c:291: warning: dereferencing pointer '__u' does break strict-aliasing rules
convert.c:291: note: initialized from here
convert.c:291: warning: dereferencing pointer '__u' does break strict-aliasing rules
convert.c:291: note: initialized from here
convert.c:291: warning: dereferencing pointer '__u' does break strict-aliasing rules
convert.c:291: note: initialized from here
convert.c:291: warning: dereferencing pointer '__u' does break strict-aliasing rules
convert.c:291: note: initialized from here
    CC copy.o
    CC csum-file.o
    CC ctype.o
    CC date.o
    CC decorate.o
    CC diffcore-break.o
    CC diffcore-delta.o
    CC diffcore-order.o
    CC diffcore-pickaxe.o
    CC diffcore-rename.o
    CC diff-delta.o
    CC diff-lib.o
    CC diff-no-index.o
    CC diff.o
diff.c: In function 'diff_words_show':
diff.c:711: warning: dereferencing pointer '__u' does break strict-aliasing rules
diff.c:711: note: initialized from here
diff.c: In function 'diff_get_patch_id':
diff.c:3317: warning: dereferencing pointer '__u' does break strict-aliasing rules
diff.c:3317: note: initialized from here
diff.c:3328: warning: dereferencing pointer '__u' does break strict-aliasing rules
diff.c:3328: note: initialized from here
diff.c: In function 'builtin_diffstat':
diff.c:1815: warning: dereferencing pointer '__u' does break strict-aliasing rules
diff.c:1815: note: initialized from here
diff.c: In function 'run_diff_cmd':
diff.c:1718: warning: dereferencing pointer '__u' does break strict-aliasing rules
diff.c:1718: note: initialized from here
diff.c: In function 'diff_flush':
diff.c:1862: warning: dereferencing pointer '__u' does break strict-aliasing rules
diff.c:1862: note: initialized from here
diff.c:3461: warning: dereferencing pointer '__u' does break strict-aliasing rules
diff.c:3461: note: initialized from here
    CC dir.o
    CC editor.o
    CC entry.o
    CC environment.o
    CC exec_cmd.o
    CC fsck.o
    CC graph.o
    CC grep.o
    CC hash.o
    CC help.o
help.c: In function 'help_unknown_cmd':
help.c:308: warning: dereferencing pointer '__u' does break strict-aliasing rules
help.c:308: note: initialized from here
help.c:309: warning: dereferencing pointer '__u' does break strict-aliasing rules
help.c:309: note: initialized from here
help.c:310: warning: dereferencing pointer '__u' does break strict-aliasing rules
help.c:310: note: initialized from here
    CC ident.o
    CC levenshtein.o
    CC list-objects.o
    CC ll-merge.o
ll-merge.c: In function 'll_xdl_merge':
ll-merge.c:79: warning: dereferencing pointer '__u' does break strict-aliasing rules
ll-merge.c:79: note: initialized from here
    CC lockfile.o
    CC log-tree.o
    CC mailmap.o
    CC match-trees.o
    CC merge-file.o
merge-file.c: In function 'merge_file':
merge-file.c:64: warning: dereferencing pointer '__u' does break strict-aliasing rules
merge-file.c:64: note: initialized from here
merge-file.c:33: warning: dereferencing pointer '__u' does break strict-aliasing rules
merge-file.c:33: note: initialized from here
    CC merge-recursive.o
    CC name-hash.o
    CC notes.o
    CC object.o
    CC pack-check.o
    CC pack-refs.o
pack-refs.c: In function 'pack_refs':
pack-refs.c:89: warning: dereferencing pointer '__u' does break strict-aliasing rules
pack-refs.c:89: note: initialized from here
pack-refs.c:89: warning: dereferencing pointer '__u' does break strict-aliasing rules
pack-refs.c:89: note: initialized from here
pack-refs.c:89: warning: dereferencing pointer '__u' does break strict-aliasing rules
pack-refs.c:89: note: initialized from here
    CC pack-revindex.o
    CC pack-write.o
    CC pager.o
    CC parse-options.o
    CC patch-delta.o
    CC patch-ids.o
    CC path.o
    CC pkt-line.o
    CC preload-index.o
    CC pretty.o
    CC progress.o
    CC quote.o
    CC reachable.o
    CC read-cache.o
read-cache.c: In function 'fill_stat_cache_info':
read-cache.c:72: error: 'struct stat' has no member named 'st_ctim'
read-cache.c:73: error: 'struct stat' has no member named 'st_mtim'
read-cache.c: In function 'read_index_from':
read-cache.c:1316: error: 'struct stat' has no member named 'st_mtim'
read-cache.c: In function 'write_index':
read-cache.c:1581: error: 'struct stat' has no member named 'st_mtim'
make: *** [read-cache.o] Error 1

Re: git 1.6.6.1 on glibc 2.2

[Jonathan Nieder]

Hi!

Gabor Z. Papp wrote:
> Hello all,
> 
> trying to compile git 1.6.6.1 on Linux 2.4.37.7, glibc 2.2.5:
> 
> read-cache.c: In function 'fill_stat_cache_info':
> read-cache.c:72: error: 'struct stat' has no member named 'st_ctim'

Thanks for the report.  Perhaps:

$ grep -C3 st_ctim Makefile
# randomly break unless your underlying filesystem supports those sub-second
# times (my ext3 doesn't).
#
# Define USE_ST_TIMESPEC if your "struct stat" uses "st_ctimespec" instead of
# "st_ctim"
#
# Define NO_NSEC if your "struct stat" does not have "st_ctim.tv_nsec"
# available.  This automatically turns USE_NSEC off.
#
# Define USE_STDEV below if you want git to care about the underlying device

Hope that helps,
Jonathan

Re: git 1.6.6.1 on glibc 2.2

[Gabor Z. Papp]

* Jonathan Nieder <jrnieder@gmail.com>:

| > trying to compile git 1.6.6.1 on Linux 2.4.37.7, glibc 2.2.5:
| > 
| > read-cache.c: In function 'fill_stat_cache_info':
| > read-cache.c:72: error: 'struct stat' has no member named 'st_ctim'

| Thanks for the report.  Perhaps:
| # Define NO_NSEC if your "struct stat" does not have "st_ctim.tv_nsec"
| # available.  This automatically turns USE_NSEC off.

Thanks Jonathan, compiles fine defining NO_NSEC, but my glibc is 2.2.5
and the comment abot USE_NSEC says it requires at least glibc
2.2.4. Maybe the comment is wrong? glibc 2.3.6 compiles fine.

Re: git 1.6.6.1 on glibc 2.2

[Jonathan Nieder]

Gabor Z. Papp wrote:
>| Gabor Z. Papp wrote:
 
>|> trying to compile git 1.6.6.1 on Linux 2.4.37.7, glibc 2.2.5:
>|> 
>|> read-cache.c: In function 'fill_stat_cache_info':
>|> read-cache.c:72: error: 'struct stat' has no member named 'st_ctim'
[...] 
> Thanks Jonathan, compiles fine defining NO_NSEC, but my glibc is 2.2.5
> and the comment abot USE_NSEC says it requires at least glibc
> 2.2.4. Maybe the comment is wrong? glibc 2.3.6 compiles fine.

Hmm, in the glibc changelog I find this, from ChangeLog.14:

| 2003-01-04  Andreas Schwab  <schwab@suse.de>
|
|	* sysdeps/unix/sysv/linux/m68k/bits/stat.h: Add nanosecond fields.

That’s around the time of glibc 2.3.2.

The stat(2) man page tells a little more:

| Since kernel 2.5.48, the stat structure supports nanosecond resolution for
| the  three  file timestamp fields.  Glibc exposes the nanosecond component
| of each field using names either  of  the  form  st_atim.tv_nsec,  if  the
| _BSD_SOURCE  or _SVID_SOURCE feature test macro is defined, or of the form
| st_atimensec, if neither of these macros is defined.  On file systems that
| do not support sub-second timestamps, these nanosecond fields are returned
| with the value 0.

Searching a little harder yields commit cvs/glibc-2_3_2~418
(2002-12-31) of git://sourceware.org/git/glibc.git, in which the
feature was added.  There’s a lovely discussion about it from then on
libc-alpha. [1]

The comment you mention is from commit bdd4da5 (Make nsec checking
optional, 2005-04-13); I am guessing 2.2.4 was just mentioned as a lower
bound.

So how about something like the following?  Please feel free to
write something better --- in particular, I am not sure the
documentation for USE_NSEC is the most obvious place to look when
something goes wrong.

Thanks,
Jonathan

[1] http://sourceware.org/ml/libc-alpha/2002-12/threads.html#00011

-- %< --
Subject: Makefile: document minimal glibc version supporting tv_nsec

Compiling git with the default settings and old glibc produces
errors like the following:

| read-cache.c: In function 'fill_stat_cache_info':
| read-cache.c:72: error: 'struct stat' has no member named 'st_ctim'

The Makefile seems to imply that versions after 2.2.4 should be
okay, but that is not true: NO_NSEC must be set to build with
glibc versions before 2.3.2.

Reported-by: Gabor Z. Papp <gzp@papp.hu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
diff --git a/Makefile b/Makefile
index fd7f51e..8ebc966 100644
--- a/Makefile
+++ b/Makefile
@@ -134,7 +134,7 @@ all::
 # "-Wl,-rpath=/path/lib" is used instead.
 #
 # Define USE_NSEC below if you want git to care about sub-second file mtimes
-# and ctimes. Note that you need recent glibc (at least 2.2.4) for this, and
+# and ctimes. Note that you need recent glibc (at least 2.3.2) for this, and
 # it will BREAK YOUR LOCAL DIFFS! show-diff and anything using it will likely
 # randomly break unless your underlying filesystem supports those sub-second
 # times (my ext3 doesn't).