On Sat, Jun 26, 2010 at 11:21:37PM +0000, David Holland wrote: > On Sat, Jun 26, 2010 at 06:25:23AM +0200, Joerg Sonnenberger wrote: > > > It would be better to make this a check which is size_t dependent, > > > rather than platform-dependent. > > > > The idea is to black list platforms that don't do %zu and there is no > > way to do that without breaking cross-compilation. It is still > > preferable to use that if it is available, e.g. to help format string > > checks. > > Compromising the autoconfiguration not work properly in the name of > cross-compilation, though, is misguided. Can't you have it run the > test if it's not a cross-compiler and only if it is fall back to the > platform test? Or is this one of the things where autoconf falls apart > because it's not written in a programming language?
You can by using AC_RUN_IFELSE directly. The fourth argument is the cross-compiling test. > I suppose the best available comprehensive solution is to use PRIu*** > garble in the code and then if necessary have autoconf figure out what > the garble should expand to based on SIZE_MAX. The trivial example was FreeBSD 4.x, but I would expect platforms with %zu to fall into this category too. > (not counting where it might technically be 0x7fffffff because someone > was unclear on it being unsigned -- that doesn't affect printf) SSIZE_MAX is surprisingly a lot better supported... > > > I still don't understand why autoconf is passing C pre-processor > > > directives down. > > > > > > #if sizeof(size_t) == sizeof(int) > > > ... > > > #elif sizeof(size_t) == sizeof(long) > > > ... > > > #endif > > > > > > directly in the code is much more readable. > > It would be nice if that worked... it did in Borland's compiler back > in the day. I suppose someone on the standards committee thought it > was OK to have to teach the preprocessor the entire expression syntax > but not the type name syntax... The problem is that you can't really evuluate the above with interpreting all of the C code before. size_t is not a "keyword" type in the sense that it is hard-coded into the compiler. Doing so would violate the layering design of the preprocessor. Joerg
