HYPOT(3)               FreeBSD Library Functions Manual               HYPOT(3)

NAME
     hypot, hypotf, hypotl, cabs, cabsf, cabsl - Euclidean distance and
     complex absolute value functions

LIBRARY
     Math Library (libm, -lm)

SYNOPSIS
     #include <math.h>

     double
     hypot(double x, double y);

     float
     hypotf(float x, float y);

     long double
     hypotl(long double x, long double y);

     #include <complex.h>

     double
     cabs(double complex z);

     float
     cabsf(float complex z);

     long double
     cabsl(long double complex z);

DESCRIPTION
     The hypot(), hypotf() and hypotl() functions compute the sqrt(x*x+y*y) in
     such a way that underflow will not happen, and overflow occurs only if
     the final result deserves it.  The cabs(), cabsf() and cabsl() functions
     compute the complex absolute value of z.

     hypot(infinity, v) = hypot(v, infinity) = +infinity for all v, including
     NaN.

ERROR (due to Roundoff, etc.)
     Below 0.97 ulps.  Consequently hypot(5.0, 12.0) = 13.0 exactly; in
     general, hypot and cabs return an integer whenever an integer might be
     expected.

NOTES
     As might be expected, hypot(v, NaN) and hypot(NaN, v) are NaN for all
     finite v.  But programmers might be surprised at first to discover that
     hypot(+-infinity, NaN) = +infinity.  This is intentional; it happens
     because hypot(infinity, v) = +infinity for all v, finite or infinite.
     Hence hypot(infinity, v) is independent of v.  Unlike the reserved
     operand fault on a VAX, the IEEE NaN is designed to disappear when it
     turns out to be irrelevant, as it does in hypot(infinity, NaN).

SEE ALSO
     carg(3), math(3), sqrt(3)

STANDARDS
     The hypot(), hypotf(), hypotl(), cabs(), cabsf(), and cabsl() functions
     conform to ISO/IEC 9899:1999 ("ISO C99").

HISTORY
     Both a hypot() function and a cabs() function appeared in Version 7 AT&T
     UNIX.

FreeBSD 13.1-RELEASE-p6         March 30, 2008         FreeBSD 13.1-RELEASE-p6