функция евклидова расстояния (euclidean distance function)
Имя (Name)
hypot, hypotf, hypotl - Euclidean distance function
Синопсис (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 <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
hypotf(), hypotl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Описание (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.
Возвращаемое значение (Return value)
On success, these functions return the length of the hypotenuse
of a right-angled triangle 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.
Ошибки (Error)
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.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│hypot(), hypotf(), hypotl() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
Стандарты (Conforming to)
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning double also conforms to SVr4, 4.3BSD.
Смотри также (See also)
cabs(3), sqrt(3)
