1clog(3)                    Library Functions Manual                    clog(3)
2
3
4

NAME

6       clog, clogf, clogl - natural logarithm of a complex number
7

LIBRARY

9       Math library (libm, -lm)
10

SYNOPSIS

12       #include <complex.h>
13
14       double complex clog(double complex z);
15       float complex clogf(float complex z);
16       long double complex clogl(long double complex z);
17

DESCRIPTION

19       These  functions  calculate  the complex natural logarithm of z, with a
20       branch cut along the negative real axis.
21
22       The logarithm  clog()  is  the  inverse  function  of  the  exponential
23       cexp(3).   Thus,  if y = clog(z), then z = cexp(y).  The imaginary part
24       of y is chosen in the interval [-pi,pi].
25
26       One has:
27
28           clog(z) = log(cabs(z)) + I * carg(z)
29
30       Note that z close to zero will cause an overflow.
31

ATTRIBUTES

33       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
34       tributes(7).
35
36       ┌────────────────────────────────────────────┬───────────────┬─────────┐
37Interface                                   Attribute     Value   
38       ├────────────────────────────────────────────┼───────────────┼─────────┤
39clog(), clogf(), clogl()                    │ Thread safety │ MT-Safe │
40       └────────────────────────────────────────────┴───────────────┴─────────┘
41

STANDARDS

43       C11, POSIX.1-2008.
44

HISTORY

46       glibc 2.1.  C99, POSIX.1-2001.
47

SEE ALSO

49       cabs(3), cexp(3), clog10(3), clog2(3), complex(7)
50
51
52
53Linux man-pages 6.05              2023-07-20                           clog(3)
Impressum