SQRT
Section: Linux Programmer's Manual (3)
Updated: 20170915
Page Index
NAME
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 floatingpoint 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  MTSafe

CONFORMING TO
C99, POSIX.12001, POSIX.12008.
The variant returning
double
also conforms to
SVr4, 4.3BSD, C89.
SEE ALSO
cbrt(3),
csqrt(3),
hypot(3)
COLOPHON
This page is part of release 5.02 of the Linux
manpages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/manpages/.