# engSetEvalCallback

## Purpose

Enable nonblocking `engEvalString` calls.

## Syntax

    #include "engine.h"
    void engSetEvalCallback(ep,callback)
            Engine *ep;
            void (*callback)();

## Arguments

`ep`
  engine pointer
`callback`
  pointer to callback function

## Description

DDE, the protocol that MATLAB engines use to communicate with your program, can operate in both synchronous and asynchronous modes. The default behavior of `engEvalString` is to block until the specified command is completed.

`engEvalString` is set to operate in a nonblocking mode by calling `engSetEvalCallback`. The specified callback function is executed upon completion of the MATLAB command. This allows you to take appropriate action upon notification.

(c) Copyright 1994 by The MathWorks, Inc.