Returns the complex arc hyperbolic cosine of its argument.

    This function is supported on OpenVMS Integrity servers and
    Alpha only.

    Format

      #include  <complex.h>

      double complex cacosh  (double complex z);

      float complex cacoshf  (float complex z);

      long double complex cacoshl  (long double complex z);

1 - Argument

 z

    A complex value.

2 - Description

    The cacosh functions compute the complex arc hyperbolic cosine of
    z, with a branch cut at values less than 1 along the real axis.

3 - Return Values

    n                  The complex arc hyperbolic cosine value, in
                       the range of a half-strip of non-negative
                       values along the real axis and in the interval
                       [-iπ, +iπ] along the imaginary axis.