projects / thirdparty / man-pages.git / blame
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|---|---|---|
| fea681da | 1 | .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) |
| 2297bf0e | 2 | .\" |
| 38f20bb9 | 3 | .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE) |
| fea681da | 4 | .\" Distributed under GPL |
| 38f20bb9 | 5 | .\" %%%LICENSE_END |
| fea681da | 6 | .\" |
| 4b8c67d9 | 7 | .TH CLOG 3 2017-09-15 "" "Linux Programmer's Manual" |
| fea681da MK |
8 | .SH NAME |
| 9 | clog, clogf, clogl \- natural logarithm of a complex number | |
| 10 | .SH SYNOPSIS | |
| 11 | .B #include <complex.h> | |
| 68e4db0a | 12 | .PP |
| fea681da | 13 | .BI "double complex clog(double complex " z ); |
| d39541ec | 14 | .br |
| fea681da | 15 | .BI "float complex clogf(float complex " z ); |
| d39541ec | 16 | .br |
| fea681da | 17 | .BI "long double complex clogl(long double complex " z ); |
| 68e4db0a | 18 | .PP |
| 20c58d70 | 19 | Link with \fI\-lm\fP. |
| fea681da | 20 | .SH DESCRIPTION |
| 7dffdbbd | 21 | These functions calculate the complex natural logarithm of |
| defcc338 MK |
22 | .IR z , |
| 23 | with a branch cut along the negative real axis. | |
| 847e0d88 | 24 | .PP |
| c1f2e990 MK |
25 | The logarithm |
| 26 | .BR clog () | |
| 27 | is the inverse function of the exponential | |
| 28 | .BR cexp (3). | |
| 658670de | 29 | Thus, if \fIy\ =\ clog(z)\fP, then \fIz\ =\ cexp(y)\fP. |
| c13182ef MK |
30 | The imaginary part of |
| 31 | .I y | |
| e17f9d28 | 32 | is chosen in the interval [\-pi,pi]. |
| dd3568a1 | 33 | .PP |
| 658670de | 34 | One has: |
| 207050fa | 35 | .PP |
| 658670de | 36 | .nf |
| 658670de MK |
37 | clog(z) = log(cabs(z)) + I * carg(z) |
| 38 | .fi | |
| dd3568a1 | 39 | .PP |
| c13182ef MK |
40 | Note that |
| 41 | .I z | |
| 42 | close to zero will cause an overflow. | |
| f0d7ce1d MK |
43 | .SH VERSIONS |
| 44 | These functions first appeared in glibc in version 2.1. | |
| 4e1c6675 MS |
45 | .SH ATTRIBUTES |
| 46 | For an explanation of the terms used in this section, see | |
| 47 | .BR attributes (7). | |
| 48 | .TS | |
| 49 | allbox; | |
| 50 | lbw24 lb lb | |
| 51 | l l l. | |
| 52 | Interface Attribute Value | |
| 53 | T{ | |
| 54 | .BR clog (), | |
| 55 | .BR clogf (), | |
| 56 | .BR clogl () | |
| 57 | T} Thread safety MT-Safe | |
| 58 | .TE | |
| 47297adb | 59 | .SH CONFORMING TO |
| 9a74e018 | 60 | C99, POSIX.1-2001, POSIX.1-2008. |
| 47297adb | 61 | .SH SEE ALSO |
| fea681da MK |
62 | .BR cabs (3), |
| 63 | .BR cexp (3), | |
| 64 | .BR clog10 (3), | |
| 75398312 | 65 | .BR clog2 (3), |
| a8bda636 | 66 | .BR complex (7) |