RE: cos() in math.h ?

["Sean 'Shaleh' Perry" <shaleh@valinux.com>]

On 03-Aug-2000 Christophe TROESTLER wrote:
> Hi all,
> 
> According to the man page, if I want to use `cos' in a program, I
> simply need to include `math.h'.  However, when I compile, I got the
> error:
> 
>       /tmp/cc9WOsLC.o(.text+0x16): undefined reference to `cos'
>       collect2: ld returned 1 exit status
> 
> I got the necessary packages to compile (e.g., libc6-dev).  Any idea
> what is the cause ?
> 

when you use something from math.h you have to link with libmath, using -lm on
the command line:

gcc foo.c -lm -o foo