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CLOG(3) Linux Programmer's Manual CLOG(3)

NAME

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

SYNOPSIS

     #include <complex.h>

     double complex clog(double complex z);
     float complex clogf(float complex z);
     long double complex clogl(long double complex z);

     Link with -lm.

DESCRIPTION

     These  functions  calculate  the complex natural logarithm of z, with a
     branch cut along the negative real axis.

     The logarithm  clog()  is  the  inverse  function  of  the  exponential
     cexp(3).   Thus,  if y = clog(z), then z = cexp(y).  The imaginary part
     of y is chosen in the interval [-pi,pi].

     One has:

         clog(z) = log(cabs(z)) + I * carg(z)

     Note that z close to zero will cause an overflow.

VERSIONS

     These functions first appeared in glibc in version 2.1.

ATTRIBUTES

     For  an  explanation  of  the  terms  used   in   this   section,   see
     attributes(7).

     allbox;  lbw24  lb  lb  l  l  l.   Interface Attribute Value T{ clog(),
     clogf(), clogl() T}   Thread safety  MT-Safe

CONFORMING TO

     C99, POSIX.1-2001, POSIX.1-2008.

SEE ALSO

     cabs(3), cexp(3), clog10(3), clog2(3), complex(7)

COLOPHON

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     description  of  the project, information about reporting bugs, and the
     latest    version    of    this    page,    can     be     found     at
     https://www.kernel.org/doc/man-pages/.

                                2017-09-15                           CLOG(3)