| .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
| .\" |
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| .\" manual under the conditions for verbatim copying, provided that the |
| .\" entire resulting derived work is distributed under the terms of a |
| .\" permission notice identical to this one. |
| .\" |
| .\" Since the Linux kernel and libraries are constantly changing, this |
| .\" manual page may be incorrect or out-of-date. The author(s) assume no |
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| .\" 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 2021-03-22 "" "Linux Programmer's Manual" |
| .SH NAME |
| hypot, hypotf, hypotl \- Euclidean distance function |
| .SH SYNOPSIS |
| .nf |
| .B #include <math.h> |
| .PP |
| .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 |
| .PP |
| Link with \fI\-lm\fP. |
| .PP |
| .RS -4 |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .RE |
| .PP |
| .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 |
| .PP |
| .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. |
| .PP |
| 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 . |
| .PP |
| If |
| .I x |
| or |
| .I y |
| is an infinity, |
| positive infinity is returned. |
| .PP |
| If |
| .I x |
| or |
| .I y |
| is a NaN, |
| and the other argument is not an infinity, |
| a NaN is returned. |
| .PP |
| If the result overflows, |
| a range error occurs, |
| and the functions return |
| .BR HUGE_VAL , |
| .BR HUGE_VALF , |
| or |
| .BR HUGE_VALL , |
| respectively. |
| .PP |
| 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. |
| .PP |
| 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 |
| .IR 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). |
| .ad l |
| .nh |
| .TS |
| allbox; |
| lbx lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR hypot (), |
| .BR hypotf (), |
| .BR hypotl () |
| T} Thread safety MT-Safe |
| .TE |
| .hy |
| .ad |
| .sp 1 |
| .SH CONFORMING TO |
| C99, POSIX.1-2001, POSIX.1-2008. |
| .PP |
| The variant returning |
| .I double |
| also conforms to |
| SVr4, 4.3BSD. |
| .SH SEE ALSO |
| .BR cabs (3), |
| .BR sqrt (3) |