pre2 problem with gcc option

Tomas Styblo tripie at cpan.org
Sat Jan 4 10:10:05 UTC 2003


* Pavel Roskin <proski at gnu.org> [Thu, 02 Jan 2003]:
> Maybe this option breaks ABI compatibility - then it's
> not a bug.

Yes it breaks ABI compatibility.

[SNIP]

> When compiled with -mdouble-align, MC does not funtion
> correctly, namely all file sizes are displayed the same (some
> number like 16000G) and viewing, editing or anything else does
> not work (file empty etc.). It is specifically this option that
> causes the problem...I tracked it down by adding one option at a
> time and no problems until this one. Took it back out again...no
> problem.

gcc documentation says:

  -malign-double
  -mno-align-double

      Control whether GNU CC aligns "double", "long double", and
      "long long" variables on a two word boundary or a one word
      boundary. Aligning "double" variables on a two word boundary
      will produce code that runs somewhat faster on a `Pentium`
      at the expense of more memory.  WARNING: if you use the
      `-malign-double` switch, structures containing the above
      types will be aligned differently than the published
      application binary interface specifications for the 386. 

I think the problem happens when working with the "st_size" memeber 
of the "stat" structure. I suppose the "off_t" type is a typedef of
"long long" on that user's machine.

-- 
Tomas Styblo <tripie at cpan.org>
PGP: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xC97EA4B6



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