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
       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.

CONFORMING TO
       C99.

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

COLOPHON
       This  page  is  part of release 3.74 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at http://www.kernel.org/doc/man-pages/.



                                            2008-08-11                                    CLOG(3)