'\" t .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) .\" .\" SPDX-License-Identifier: Linux-man-pages-copyleft .\" .\" References consulted: .\" Linux libc source code .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) .\" 386BSD man pages .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) .\" Modified 2002-07-27 by Walter Harms .\" (walter.harms@informatik.uni-oldenburg.de) .\" .TH hypot 3 2024-05-02 "Linux man-pages 6.9.1" .SH NAME hypot, hypotf, hypotl \- Euclidean distance function .SH LIBRARY Math library .RI ( libm ", " \-lm ) .SH SYNOPSIS .nf .B #include .P .BI "double hypot(double " x ", double " y ); .BI "float hypotf(float " x ", float " y ); .BI "long double hypotl(long double " x ", long double " y ); .fi .P .RS -4 Feature Test Macro Requirements for glibc (see .BR feature_test_macros (7)): .RE .P .BR hypot (): .nf _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE .fi .P .BR hypotf (), .BR hypotl (): .nf _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE .fi .SH DESCRIPTION These functions return .RI sqrt( x * x + y * y ). This is the length of the hypotenuse of a right-angled triangle with sides of length .I x and .IR y , or the distance of the point .RI ( x , y ) from the origin. .P The calculation is performed without undue overflow or underflow during the intermediate steps of the calculation. .\" e.g., hypot(DBL_MIN, DBL_MIN) does the right thing, as does, say .\" hypot(DBL_MAX/2.0, DBL_MAX/2.0). .SH RETURN VALUE On success, these functions return the length of the hypotenuse of a right-angled triangle with sides of length .I x and .IR y . .P If .I x or .I y is an infinity, positive infinity is returned. .P If .I x or .I y is a NaN, and the other argument is not an infinity, a NaN is returned. .P If the result overflows, a range error occurs, and the functions return .BR HUGE_VAL , .BR HUGE_VALF , or .BR HUGE_VALL , respectively. .P If both arguments are subnormal, and the result is subnormal, .\" Actually, could the result not be subnormal if both arguments .\" are subnormal? I think not -- mtk, Jul 2008 a range error occurs, and the correct result is returned. .SH ERRORS See .BR math_error (7) for information on how to determine whether an error has occurred when calling these functions. .P The following errors can occur: .TP Range error: result overflow .I errno is set to .BR ERANGE . An overflow floating-point exception .RB ( FE_OVERFLOW ) is raised. .TP Range error: result underflow An underflow floating-point exception .RB ( FE_UNDERFLOW ) is raised. .IP These functions do not set .I errno for this case. .\" This is intentional; see .\" https://www.sourceware.org/bugzilla/show_bug.cgi?id=6795 .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). .TS allbox; lbx lb lb l l l. Interface Attribute Value T{ .na .nh .BR hypot (), .BR hypotf (), .BR hypotl () T} Thread safety MT-Safe .TE .SH STANDARDS C11, POSIX.1-2008. .SH HISTORY C99, POSIX.1-2001. .P The variant returning .I double also conforms to SVr4, 4.3BSD. .SH SEE ALSO .BR cabs (3), .BR sqrt (3)