1.55 sqrt, sqrtf—positive square root

Synopsis

#include <math.h>
double sqrt(double x);
float  sqrtf(float x);

Description
sqrt computes the positive square root of the argument.

Returns
On success, the square root is returned. If x is real and positive, then the result is positive. If x is real and negative, the global value errno is set to EDOM (domain error).

Portability
sqrt is ANSI C. sqrtf is an extension.