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Re: Report bugs for variations in error handling in math functions?
On Fri, 25 Jul 2008, Michael Kerrisk wrote:
> Not even one approach is consistent. Many functions don't set errno.
> But there are one or two that don't raise exceptions: the Bessel
> functions (j0(), y0 etc), for example. It's all a bit of a mess,
> unfortunately.
Those functions aren't in C99. They are however in POSIX, which defines
C99-like error handling requirements, though a lot of errors are "may
occur" just as a lot of C99 ones are. (But if a "may occur" error is
indicated by one of errno and exceptions, it must be indicated by both if
math_errhandling says both forms of error handling are supported.)
(Bessel functions under different names and a lot of other functions are
in DIS 24747, which passed its ballot for approval as an International
Standard. But I don't expect it to be integrated in the next revision of
the C standard; my understanding is also that all of C++ TR1 *apart* from
special mathematical functions (much the same set) is being integrated in
C++0x.)
--
Joseph S. Myers
joseph@codesourcery.com