?
Solved

DLL call functions in program running it?

Posted on 2007-03-28
3
Medium Priority
?
229 Views
Last Modified: 2010-04-05
Is it possible for a DLL to call functions in the program which is running the DLL?

I can do this with window messages but is that the only way?

Surely the DLL can have some kind of access to the program which is using it?
0
Comment
Question by:TheJkWhoSaysNi
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
3 Comments
 
LVL 21

Assisted Solution

by:ziolko
ziolko earned 240 total points
ID: 18814240
yup it's called callback.

look at one of my PAQ's:
http://www.experts-exchange.com/Programming/Languages/Pascal/Delphi/Q_20080180.html

ziolko.
0
 
LVL 17

Accepted Solution

by:
Wim ten Brink earned 260 total points
ID: 18815001
Or an easier method: export your methods in your executable!!! Example:
------------------------------------------------------------
program EXE;
{$APPTYPE CONSOLE}
uses Windows;

procedure Callback; export;
begin
  WriteLn('Callback called');
end;

exports
  Callback;

var
  DLLHandle: THandle;
begin
  DLLHandle := LoadLibrary('DLL.dll');
  ReadLn;
  CloseHandle(DLLHandle);
end.
------------------------------------------------------------
library DLL;

uses
  Windows;

type
  TCallback = procedure;

var
  Callback: TCallback;
begin
  Callback := GetProcAddress(MainInstance, 'Callback');
  Callback;
end.
------------------------------------------------------------
Basically, what it does is that the DLL will look for the method called "Callback" in the instance of the executable. Since the executable exports this method, it can easily call this method even without the EXE first having to tell the DLL where to find the method. :-)
0
 

Author Comment

by:TheJkWhoSaysNi
ID: 18818931
Thanks to both of you. I'll split the points. Going to try both methods :)

Thanks ziolko and Workshop_Alex.
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

The uses clause is one of those things that just tends to grow and grow. Most of the time this is in the main form, as it's from this form that all others are called. If you have a big application (including many forms), the uses clause in the in…
Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
NetCrunch network monitor is a highly extensive platform for network monitoring and alert generation. In this video you'll see a live demo of NetCrunch with most notable features explained in a walk-through manner. You'll also get to know the philos…
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…
Suggested Courses

770 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question