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HYPOT(3) Linux Programmer's Manual HYPOT(3)

NAME

     hypot, hypotf, hypotl - Euclidean distance function

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);

     Link with -lm.

 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

     hypot():
         _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
             || _XOPEN_SOURCE
             || /* Since glibc 2.19: */ _DEFAULT_SOURCE
             || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
     hypotf(), hypotl():
         _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
             || /* Since glibc 2.19: */ _DEFAULT_SOURCE
             || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

     These  functions  return  sqrt(x*x+y*y).   This  is  the  length of the
     hypotenuse of a right-angled triangle with sides of length x and y,  or
     the distance of the point (x,y) from the origin.

     The calculation is performed without undue overflow or underflow during
     the intermediate steps of the calculation.

RETURN VALUE

     On success, these functions return the length of a right-angled  trian-
     gle with sides of length x and y.

     If x or y is an infinity, positive infinity is returned.

     If x or y is a NaN, and the other argument is not an infinity, a NaN is
     returned.

     If the result overflows, a range error occurs, and the functions return
     HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively.

     If  both  arguments are subnormal, and the result is subnormal, a range
     error occurs, and the correct result 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:

     Range error: result overflow
            errno  is  set  to ERANGE.  An overflow floating-point exception
            (FE_OVERFLOW) is raised.

     Range error: result underflow
            An underflow floating-point exception (FE_UNDERFLOW) is  raised.

            These functions do not set errno for this case.

ATTRIBUTES

     For   an   explanation   of   the  terms  used  in  this  section,  see
     attributes(7).

     allbox; lbw27 lb lb  l  l  l.   Interface Attribute Value  T{  hypot(),
     hypotf(), hypotl() T}   Thread safety  MT-Safe

CONFORMING TO

     C99, POSIX.1-2001, POSIX.1-2008.

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