Solved

My Cardinal is signed !

Posted on 2000-04-11
6
232 Views
Last Modified: 2011-04-14
According to the Delphi 3 Help file, cardinals are meant to be a 32 bit unsigned number.

However it is definately a 32 bit signed number on my system. (WinNT)

Try typing '(cardinal($7FFFFFFF)+1)' in the 'evaluate/modify' window and you will get a range check error instead of the correct answer of $80000000.

Also Cardinal($FFFFFFFF) gives '-1'.

Q1. Is this unique to me or does everyone else have the same issue?

Q2. So how do I get a 32 bit unsigned number?  (Simply printing it out differently at the end doesn't help, because the maths in the middle should be correct to)

(For example: $8000 0000 / 2 = ??
  Signed:   $C000 0000
  Unsigned: $4000 0000)

0
Comment
Question by:mac_rowe
  • 2
  • 2
  • 2
6 Comments
 
LVL 12

Accepted Solution

by:
rwilson032697 earned 100 total points
Comment Utility
I have noticed that various debug windows sometimes 'lie' about the real value of a variable, and at other times can do strange things as you describe.

However, cardinal is NOT a 32 bit unsigned int in D3 - it is a 31 bit unsigned int!

In D5 (D4 too, I think, but not sure) cardinal is a 32 bit unsigned int.

D5 also has LongWord which is 32 bit unsigned, but I am not sure if D3 has this.

You could do the maths in a float variable and round() the result, or it you are just doing things like DIV by 2, then you can use SHR to do it...

Cheers,

Raymond.


0
 
LVL 20

Expert Comment

by:Madshi
Comment Utility
Ray is right. D3 has no 32bit unsigned support at all. Perhaps you can use the type "comp". Not very handy though.
In D4 Borland introduced "real" 32bit unsigned support with cardinal = longWord = 32bit unsigned.

Regards, Madshi.
0
 
LVL 20

Expert Comment

by:Madshi
Comment Utility
P.S: You should seriously think about upgrading to D4 or D5, because there are tons of other quite important language extensions like int64 (real 64bit integer type), predefined parameters, function/method overloading and more...
0
Maximize Your Threat Intelligence Reporting

Reporting is one of the most important and least talked about aspects of a world-class threat intelligence program. Here’s how to do it right.

 

Author Comment

by:mac_rowe
Comment Utility
Hmm, so the Delphi documentation is a lie.  Didn't someone notice this before they released it ?

Ironically I use D5 at home but here at work we are on good ol' fashioned D3.  When you have several licenses it is quite expensive to upgrade, so I'd like to stick to D3 for the moment, rather than force the entire company to upgrade.

I've found so far the best solution is to turn range checking off and simply pretend that it is unsigned.  It is pretty good apart from the division problem mentioned earlier.

I'll check out a couple of possibilities...

0
 

Author Comment

by:mac_rowe
Comment Utility
Yes, you get a 'excellent' grade for proving to me that I wasn't mad after all.

0
 
LVL 12

Expert Comment

by:rwilson032697
Comment Utility
Your welcome!

Cheers,

Raymond.
0

Featured Post

Free Trending Threat Insights Every Day

Enhance your security with threat intelligence from the web. Get trending threat insights on hackers, exploits, and suspicious IP addresses delivered to your inbox with our free Cyber Daily.

Join & Write a Comment

A lot of questions regard threads in Delphi.   One of the more specific questions is how to show progress of the thread.   Updating a progressbar from inside a thread is a mistake. A solution to this would be to send a synchronized message to the…
Introduction Raise your hands if you were as upset with FireMonkey as I was when I discovered that there was no TListview.  I use TListView in almost all of my applications I've written, and I was not going to compromise by resorting to TStringGrid…
In this seventh video of the Xpdf series, we discuss and demonstrate the PDFfonts utility, which lists all the fonts used in a PDF file. It does this via a command line interface, making it suitable for use in programs, scripts, batch files — any pl…
This video demonstrates how to create an example email signature rule for a department in a company using CodeTwo Exchange Rules. The signature will be inserted beneath users' latest emails in conversations and will be displayed in users' Sent Items…

744 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

Need Help in Real-Time?

Connect with top rated Experts

13 Experts available now in Live!

Get 1:1 Help Now