Go forward to Index
Go backward to Math
Go up to Top
Go to the top op libm
Reentrancy Properties of `libm'
When a libm function detects an exceptional case, `errno' may be set,
the `matherr' function may be called, and a error message may be
written to the standard error stream. This behavior may not be
With reentrant C libraries like the Red Hat newlib C library,
`errno' is a macro which expands to the per-thread error value. This
makes it thread safe.
When the user provides his own `matherr' function it must be
reentrant for the math library as a whole to be reentrant.
In normal debugged programs, there are usually no math subroutine
errors--and therefore no assignments to `errno' and no `matherr' calls;
in that situation, the math functions behave reentrantly.
Created Mon Nov 8 17:42:56 2004 on tillpc with info_to_html version 0.9.6.