[LCP]Missing Prototype in math.h

[Hemant Mohan]

Hi
If I compile the following code segement  then I get the warning:

Implicit declaration of the function roundf

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

int main()
{
   float x;
   x = roundf( 10.5);
   printf("x=%f\n", x);
   return 0;
}

**********

I try to compile it using the options 
gcc -Wall -lm test.c

Further, on going through the /usr/include/math.h header
I am unable to find the prototype of the roundf function, though the man page 
suggests that it should be in the math.h header.  Similarly there is no 
prototype for round function.

Is it a known issue?

Any comments will be much appreciated.

Thanks,
Hemant