sqrt

(3)

square root function

Library functionsmanpages-dev 6.9.1-1also documents sqrtf, sqrtl

#include <math.h> double sqrt(double x); float sqrtf(float x); long double sqrtl(long double x); 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 <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

LIBRARY

Math library (libm, -lm)

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

STANDARDS

C11, POSIX.1-2008.

HISTORY

C99, POSIX.1-2001.

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