Andrew Pinski <pinskia@xxxxxxxxxxxxxx> writes: > Let me make the point that signed overflow has been undefined since > before the C standard was finialized and in fact there is a nice > paper/book called "C Traps and Pitfalls[2]" which mentions all of this > back in 1988. C Traps and Pitfalls, like K&Rv2, is derived from a draft of the C89 standard and was intended to match the final C89 standard closely. It is therefore not a reliable source of information about traditional C. K&Rv1 is a better source, and as David Daney reports in <http://gcc.gnu.org/ml/gcc/2006-12/msg00948.html> it said that integer overflow handling was machine-dependent and that all existing implementations ignored overflows. This corresponds to existing practice at the time, which was that signed overflow wrapped; but clearly there was an attempt to allow other implementations. Compiler writers have been trying to drag C users away from C's traditional wrapping semantics ever since C89 came out, but they haven't been all that succesful yet. _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
