On February 28, 2013 10:05:12 AM Roland Stigge wrote: > On 02/28/2013 04:02 PM, Steve M. Robbins wrote:
> >> This is because of WORDS_BIGENDIAN (which is either defined or > >> not) used as "#if WORDS_BIGENDIAN". > > > > That is has always been legal C preprocessor syntax (an undefined > > macro is "false") [1] so what has changed? > > > > [1] http://gcc.gnu.org/onlinedocs/cpp/If.html > > In case of undefined WORDS_BIGENDIAN, it actually works. :-) But in > case of "#define WORDS_BIGENDIAN" (as on powerpc*), the problem > occurs. Easily reproducible: > [...] > It is consistent with the phrase you are probably referring to in the > link you posted: > > "Identifiers that are not macros, which are all considered to be the > number zero. This allows you to write #if MACRO instead of #ifdef > MACRO, if you know that MACRO, when defined, will always have a > nonzero value." > > Plain "#define WORDS_BIGENDIAN" doesn't seem to provide the latter... Right. I now see that I was fooled because using -DWORDS_BIGENDIAN on the command line *seems* to just define the macro without giving it a value, same as "#define WORDS_BIGENDIAN". However, what really happens is that it's defined be value "1"; i.e. equivalent to "#define WORDS_BIGENDIAN 1". Thanks for the report and patch. -Steve -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
