Sqrt (3) Linux Manual Page

sqrt, sqrtf, sqrtl – square root function

Synopsis

#include <math.h>

double sqrt(double x);
float sqrtf(float x);
long double sqrtl(long double x);

Link with -lm. Feature Test Macro Requirements for glibc (see feature_test_macros(7)): sqrtf(), sqrtl():

_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

Description

These functions return the nonnegative square root of x.

Return Value

On success, these functions return the square root of x.

If x is a NaN, a NaN is returned.

If x is +0 (-0), +0 (-0) is returned.

If x is positive infinity, positive infinity is returned.

If x is less than -0, a domain error occurs, and a NaN is returned.

Errors

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Domain error: x less than -0: errno is set to EDOM. An invalid floating-point exception (FE_INVALID) is raised.

Attributes

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
sqrt(), sqrtf(), sqrtl()	Thread safety	MT-Safe

Conforming To

C99, POSIX.1-2001, POSIX.1-2008.

The variant returning double also conforms to SVr4, 4.3BSD, C89.

Colophon

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