math.h

[joel.sherrill at OARcorp.com (Joel Sherrill)]

Bert wrote:

> Hi, here is a newbie's question:
> i want RTEMS to do some simple calculations,
> so there are functions like "sin(x)" and
> "cos(x)" in the codes.
> but when i compile the codes, it tells me
> that "undefined reference to sin" and
> "undefined reference to cos" ...
> i have added "#include <math.h>" to the
> source code, what else should i do?

FYI this is a standard C FAQ.

math funcitons are in libm.a.  This is the
same with almost any C Compiler installation
native or cross.

You have to link your application with the math
library. This should be accomplished by getting
"-lm" added to the command that links the
application.  For simple native gcc cases, it is
something like this:

   gcc hello.c -lm -o hello

--joel

>               Bert
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