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clog(3)                    Library Functions Manual                    clog(3)

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

LIBRARY
       Math library (libm, -lm)

SYNOPSIS
       #include <complex.h>

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

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 were added in glibc 2.1.

ATTRIBUTES
       For an  explanation  of  the  terms  used  in  this  section,  see  at-
       tributes(7).

       ┌────────────────────────────────────────────┬───────────────┬─────────┐
       │InterfaceAttributeValue   │
       ├────────────────────────────────────────────┼───────────────┼─────────┤
       │clog(), clogf(), clogl()                    │ Thread safety │ MT-Safe │
       └────────────────────────────────────────────┴───────────────┴─────────┘

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

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

Linux man-pages 6.03              2022-12-15                           clog(3)

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