On 12/10/10 09:33, Ben Pfaff wrote: > Is it even necessary to drag the preprocessor into it? > > if (-1 >> 1 == 1) Yes, good point: in many cases that suffices, and if it works it's typically better to avoid the preprocessor. On 12/10/10 09:17, Andrew W. Nosenko wrote: > Why do you think that preprocessor should match the > behavior of compiler??? Because in practice, when they don't, Bad Things Happen, this being one of the least of the problems. Generally speaking, it's not worth worrying about mismatches when one mixes a preprocessor from source A (or for machine A) with a compiler from source B (or for machine B). For example, if LONG_MAX from the preprocessor is less than the actual maximum long int value supported by the compiler, then it's better to treat the weird compiler+preprocessor behavior as being buggy, and to fix the bug rather than contort the code with some complicated Autoconf test. Alternatively, if it's easy, it's even better to modify the code so that it works regardless of whether LONG_MAX is truly the maximum long int value; this avoids the need for any Autoconf or other test. The situation with -1 >> 1 is similar. _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
