Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
?
Solved

How to Check if its been assigned activated

Posted on 2011-03-23
4
Medium Priority
?
349 Views
Last Modified: 2012-05-11
Hi, I'm having a problem, I'd like to be able to know if the hook is active and filled or empty.
var
MainHook : HHOOK;


//this creates
MainHook := SetWindowsHookEx(WH_JOURNALRECORD, KeyboardHook, hInstance, 0);

//this unhooks
UnhookWindowsHookEx(MainHook);
0
Comment
Question by:eNarc
  • 2
4 Comments
 
LVL 32

Assisted Solution

by:Ephraim Wangoya
Ephraim Wangoya earned 1000 total points
ID: 35201336
Check if it returns zero

MainHook := SetWindowsHookEx(WH_JOURNALRECORD, KeyboardHook, hInstance, 0);
if MainHook > 0 then  //this was successful
  ........
0
 
LVL 24

Assisted Solution

by:jimyX
jimyX earned 500 total points
ID: 35201520
HHook is of LongWord data type so to know if it is assigned a value you have to reset its default value first then you can match it to what you have set it to otherwise it will be holding a random default value.

You can test the default value this way:
var
  MainHook : HHOOK;
begin
  Showmessage(IntToStr(MainHook));

Open in new window


As you can see it will not be easy to distinguish if it's assigned that value or it's the default.
The best thing to do is, assign your own default value, let's say ZERO, and at any point if it is holding zero then it has not not assigned a value.
var
  MainHook : HHOOK;
begin
  MainHook := 0;
  //...
  // to check if it's assigned then
  If MainHook = 0 then
    // it is not assigned

Open in new window

0
 
LVL 32

Assisted Solution

by:Ephraim Wangoya
Ephraim Wangoya earned 1000 total points
ID: 35238022

<so to know if it is assigned a value you have to reset its default value first >

No, you don't have to do that

var
   MainHook : HHOOK;
begin
   //the very first statement already assigns a value to it, you don't need to assign a default value
  MainHook := SetWindowsHookEx(WH_JOURNALRECORD, KeyboardHook, hInstance, 0);
0
 
LVL 2

Accepted Solution

by:
LelikInside earned 500 total points
ID: 35361205
if Assigned(MainHook) then...

Open in new window

0

Featured Post

Get your problem seen by more experts

Be seen. Boost your question’s priority for more expert views and faster solutions

Question has a verified solution.

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

Objective: - This article will help user in how to convert their numeric value become words. How to use 1. You can copy this code in your Unit as function 2. than you can perform your function by type this code The Code   (CODE) The Im…
Hello everybody This Article will show you how to validate number with TEdit control, What's the TEdit control? TEdit is a standard Windows edit control on a form, it allows to user to write, read and copy/paste single line of text. Usua…
Screencast - Getting to Know the Pipeline
Enter Foreign and Special Characters Enter characters you can't find on a keyboard using its ASCII code ... and learn how to make a handy reference for yourself using Excel ~ Use these codes in any Windows application! ... whether it is a Micr…
Suggested Courses
Course of the Month11 days, 8 hours left to enroll

564 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