math.h library needed?

[nimennor]

Hi,
        I was trying to write a short program, which used
        sqrt function.  Unfortunately, I ran into some
        problems.

        Simple program like this:

#include <stdio.h>
#include <math.h>

int main()
{
        double i=16.0;

        printf("%lf", sqrt(i));

        return 0;
}

        Does not compile correctly:

/tmp/cca157861.o: In function `main':
/tmp/cca157861.o(.text+0x1b): undefined reference to `sqrt'

        I recall getting similar messages when I tried to
        compile curses program without '-lncurses'.  But
        AFAIK, there is no library needed for math.h
        functions, correct?

Thanks for your time.
Nikita.