Hello, Bruno Haible <br...@clisp.org> writes:
> I meant %08X instead of %04X. DQNAN therefore likely is > FFF8000000000000 > which decomposes into > sign = 1 (irrelevant for NaNs), > exponent = 0x7FF (highest possible value) > mantissa = 0x8000000000000 > and this is precisely the common encoding of a quiet NaN > (see <http://en.wikipedia.org/wiki/Not_a_number>). Right. >> > What's the result when you compile it with cc? >> > $ cc foo.c -lm >> > $ ./a.out >> > $ echo $? >> >> 1 >> >> That's with "Compaq C V6.5-303 (dtk) on Compaq Tru64 UNIX V5.1B >> (Rev. 2650)". >> >> Should we conclude that this is a GCC bug? > > Possibly. And what result do you get with "gcc -mieee" ? It works (returns 1). The GCC manual (info "(gcc) DEC Alpha Options") reads this: `-mieee' [...] This option generates code fully IEEE compliant code [...] The resulting code is less efficient but is able to correctly support denormalized numbers and exceptional IEEE values such as not-a-number and plus/minus infinity. So people compiling with GCC on this platform should pass `-mieee' (`configure' could add it automatically.) Thanks for your help! Ludo'.
