diversion failure [was: snapshot in preparation for m4 1.4.12]

[Eric Blake]

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[dropping bug-gnulib; this appears to be only in the m4 side of things]

According to Alain Guibert on 8/8/2008 4:13 AM:
| With pleasure. My environment: old Linux box (Intel Pentium 200 MMX,
| Debian bo, kernel 2.0.40, gcc 2.7.2.1, libc 5.4.33, GNU ld cygnus-2.7.1,
| libiconv 1.12, pth 2.0.7, i586-pc-linux-gnulibc1, autoconf 2.61,
| fileutils 3.16, Make 3.75, bash 2.0.0(1)). Same as last time.
|
| | Checking ./131.diversions
| | @ ../doc/m4.texinfo:4869: Origin of test
| | ./131.diversions: stdout mismatch
| | --- m4-tmp.3414/m4-xout Fri Aug  8 09:41:33 2008
| | +++ m4-tmp.3414/m4-out  Fri Aug  8 09:41:33 2008
| | @@ -1,2 +1 @@
| | -hi
| |  0

Hmm.  When the diversion spills into a temporary file, it appears that it
is not being reread properly.  This failure scenario was common with m4
1.4.10 on platforms where fopen(file,"a+") opened at the end instead of
the beginning of the file, but that bug has since been fixed (glibc opens
at the beginning, but I'm not sure what older libc 5.x did).  This
testcase is a bit annoying to debug, because it generates more than a
megabyte of output when working properly, so it needs some filtering.  I'm
not quite sure what to do here next; perhaps an strace will be the most
helpful (assuming strace exists on your old machine).  Could you run:

$ cat > in.m4 <<\EOF
divert(1)hi
format(%1000000d,1)
EOF
$ strace -o trace.out m4 in.m4 > /dev/null

then attach trace.out (compressed, if desired)?

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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