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(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600
       || _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION
       The sqrt() function returns the non-negative 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.

CONFORMING TO
       C99, POSIX.1-2001.  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 3.23 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.