DragonFly On-Line Manual Pages

HYPOT(3)              DragonFly Library Functions Manual              HYPOT(3)

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

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.

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

     The cabs(), cabsf() and cabsl() functions return the absolute value of
     the complex number z.

ERRORS (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; with ``reserved operand'' in place of "NaN", the same is true
     on a VAX.  But programmers on machines other than a VAX (it has no
     infinity) 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
     sqrt(3)

HISTORY
     A hypot() function first appeared in Version 3 AT&T UNIX, and cabs() in
     Version 7 AT&T UNIX.

DragonFly 4.1                  January 15, 2015                  DragonFly 4.1