Tribblix: manual page: sqrt.3m

SQRT(3M) Mathematical Library Functions SQRT(3M)

NAME

sqrt, sqrtf, sqrtl - square root function

SYNOPSIS

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double sqrt(double x);

float sqrtf(float x);

long double sqrtl(long double x);

DESCRIPTION

These functions compute the square root of their argument x.

RETURN VALUES

Upon successful completion, these functions return the square root of
x.

For finite values of x < -0, a domain error occurs and either a NaN
(if supported) or an implementation-defined value is returned.

If x is NaN, a NaN is returned.

If x is +-0 or +Inf, x is returned.

If x is -Inf, a domain error occurs and a NaN is returned.

ERRORS

These functions will fail if:

Domain Error
The finite value of x is < -0 or x is -Inf.

If the integer expression (math_errhandling &
MATH_ERREXCEPT) is non-zero, the invalid floating-
point exception is raised.

The sqrt() function sets errno to EDOM if the value
of x is negative.

USAGE

An application wanting to check for exceptions should call
feclearexcept(FE_ALL_EXCEPT) before calling these functions. On
return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW |
FE_UNDERFLOW) is non-zero, an exception has been raised. An
application should either examine the return value or check the
floating point exception flags to detect exceptions.

An application can also set errno to 0 before calling sqrt(). On
return, if errno is non-zero, an error has occurred. The sqrtf() and
sqrtl() functions do not set errno.

ATTRIBUTES