[LLVMdev] [RFC] Identifying access to errno

[Kevin Schoedel]

At 8:32 ?pm -0800 2013/11/23, David Majnemer wrote:
>In error cases, they call a function call _matherr.  This function will
>typically set only errno.  However, programs which link dynamically
>against the MSVCRT are permitted to replace the function with whatever
>they want (this is documented behavior!); their _matherr might forward
>it's arguments to "fire_the_missiles".

Sounds like System V's matherr(3):
http://www.freebsd.org/cgi/man.cgi?query=matherr&manpath=SunOS+5.10

Perhaps it's worth noting (though Hal's original message hinted at it) that
post-C99 math functions need not use errno; they are permitted to instead
have a separate set of error flags, which the user can promise to ignore by
way of a standard #pragma.

-- 
Kevin Schoedel <kps at datatravelandexperiments.com> VA3TCS