Function            isgn - sign of an integer

  Syntax              #include <mathhk.h>
                      (int) isgn(x)

  Prototype in        mathhk.h

  Remarks             isgn will determine the sign of x. Zero is
                      considered positive.

                      This function is a macro.

                      The macros sgn() and sign() are defined as isgn().

  Return value        returns -1 if x is negative, otherwise 1.

  See also            fsgn(), lsgn()