On Mon, Dec 30, 2002 at 10:57:47AM -0500, Daniel Jacobowitz wrote: > On Mon, Dec 30, 2002 at 10:23:16AM -0500, H. S. Teoh wrote: > > Hi, I just confirmed that trunc() is missing from /usr/include/math.h. > > Furthermore, the following are also missing (referenced from the manpage > > of trunc()): > > - lrint > > - nearbyint > > - round > > > > Oddly, these functions do *not* appear in the libc info pages. > > Nevertheless, they are definitely in libm: > > How did you confirm that they were not in <math.h>? Judging from your > previous messages, by using cpp or building a test program. I always > recommend actually grepping around in /usr/include for them; it can be > enlightening. > > Consider this case: > #ifdef __USE_ISOC99 [snip]
Aha. That explains it. So these functions are only defined for ISO C99? (And yes, I should've grepped the headers directly. I suppose I've become a bit wary (perhaps too wary) of doing that because recently I saw a few libc bugs where clearly the bug submitter was reading the .h file but not actually trying to compile anything, and incorrectly thinking that e.g. you need to define __USE_GNU where the documentation says defining _GNU_SOURCE is sufficient. A simple compilation test quickly disproves this. At any rate, apologies for jumping to conclusions too quickly.) > They are only declared in C99 mode. I believe that is correct. Is this indicated in the docs, though? As far as I can tell, the info pages do not indicate that C99 mode is needed to use these functions. > > This is on libc6 2.3.1-8. I'm not sure I understand why they are in the > > .so but not in any header files nor in the info docs. Are there some > > standard compliance issues here that I'm not aware of? > > They're in my copy of the info docs. Try: > "info libc Arithmetic Arithmetic\ Functions Rounding\ Functions" Yeah, I must've been doing something silly when I searched the info pages (like using 'n' to find the next match, thinking it's vi. :-P) Anyway, this bug now looks like a documentation bug/deficiency. The manpages should add #define _ISO_SOURCE (or whatever the proper name was, I forgot) for these functions, and the info pages should indicate the C99 prerequisite as well. T -- And life still goes on...
