# mxIsComplex

## Purpose

Inquire whether a Matrix is complex.

## C Synopsis

    int mxIsComplex(pm)
      Matrix *pm;

## Fortran Synopsis

    integer*4 function mxIsComplex(pm)
    integer*4 pm

## Arguments

`pm`
  pointer to Matrix structure

## Description

This routine allows you to determine whether or not an imaginary part is allocated for a Matrix. The imaginary pointer `pi` is 0 (`NULL`) if a Matrix is purely real and does not have an imaginary array. If a Matrix is complex, the imaginary pointer `pi` points to a valid array of numbers.

Be sure to use `mxIsComplex` to test whether the input arguments passed to the MEX gateway function `mexFunction` are real or complex. The imaginary parts of all input Matrices to a MATLAB function are allocated if any of the input Matrices are complex.

(c) Copyright 1994 by The MathWorks, Inc.