------- Comment #3 from gdr at cs dot tamu dot edu 2006-01-22 20:42 -------
Subject: Re: Client's isnormal function is broken by cmath
"hhinnant at apple dot com" <[EMAIL PROTECTED]> writes:
| (In reply to comment #1)
| >
| > Does the problem exist if you configure with --disable-c99?
|
| I haven't tried that configuration. The docs say that setting may change
| libstdc++'s ABI.
Indeed. The question was to what extent the issue is completely fixable.
| So this is expected behavior for the default configuration?
if you keep ADL and template deduction, sort of :-)
This is the error I get:
/home/gdr/lib/gcc/i686-pc-linux-gnu/4.2.0/../../../../include/c++/4.2.0/cmath:
In function 'int __gnu_cxx::__capture_isnormal(_Tp) [with _Tp =
manager]':
/home/gdr/lib/gcc/i686-pc-linux-gnu/4.2.0/../../../../include/c++/4.2.0/cmath:537:
instantiated from 'int std::isnormal(_Tp) [with _Tp = manager]'
t.C:22: instantiated from here
/home/gdr/lib/gcc/i686-pc-linux-gnu/4.2.0/../../../../include/c++/4.2.0/cmath:466:
error: cannot convert 'manager' to 'long double' for argument '1' to 'int
__fpclassifyl(long double)'
/home/gdr/lib/gcc/i686-pc-linux-gnu/4.2.0/../../../../include/c++/4.2.0/cmath:466:
error: cannot convert 'manager' to 'double' for argument '1' to 'int
__fpclassify(double)'
/home/gdr/lib/gcc/i686-pc-linux-gnu/4.2.0/../../../../include/c++/4.2.0/cmath:466:
error: cannot convert 'manager' to 'float' for argument '1' to 'int
__fpclassifyf(float)'
which shows that std::isnormal is being used -- because it provides a
better match. Two issues here:
(1) the std::isnormal template is way too liberal -- probably needs
an enable-if decoration.
(2) std::isnormal is there only if C99 is enabled with a
compbination of C99 macro dynamic. See the contrived logic in
std_cmath.h.
(3) even when isnormal is enable-if hacked, you still potentially
run into the same problem.
-- Gaby
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25913
