Improve company productivity with a Business Account.Sign Up

x
?
Solved

Sharing CStrings and CMapStringToString in a 32 bit dll

Posted on 1998-03-12
4
Medium Priority
?
594 Views
Last Modified: 2013-11-19
I need to convert a dll that was writtin for 16bit Windows. It made use of the CString and CMapStringToString classes to hold an undefined number of dynamically created strings and shared those strings (and the CStringMap) between different executables.

Does anyone know how I can share the memory allocated by these objects, between different exes, in the 32bit world?
0
Comment
Question by:AWF
  • 3
4 Comments
 
LVL 3

Accepted Solution

by:
stefanr earned 200 total points
ID: 1316953
There is no easy way to share memory in the 32bit world. There is some ways though. You could use Memory Mapped Files (CreateFileMapping, OpenFileMapping, MapViewOfFile, UnmapViewOfFile). You could use a common DLL with a shared data segment (#pragma data_seg, not recommended though). A Named Pipe could be an alternative (or TCP/IP, NetBios, etc, if you prefer). Or the most difficult of all, ReadProcessMemory. I recommend reading "Advanced Windows" by Jeffrey Richter. He have excellent examples of most of these methods.

In any way, it seems that you by some means have to copy the contents of the memory in one process to the other (with the exception of ReadProcessMemory).

/Stefan
0
 
LVL 3

Expert Comment

by:stefanr
ID: 1316954
Correction: ReadProcessMemory copies the contents of the memory too.
0
 

Author Comment

by:AWF
ID: 1316955
Thankyou for your response. I was afraid it wasnt going to be easy! Would an alternative be to write an out of process COM server? My understanding is that this would be perfrom quite slowly though
0
 
LVL 3

Expert Comment

by:stefanr
ID: 1316956
Personally I wouldn't worry so much about the performance as what parameters I am allowed to use when calling a DCOM server. Basically a DCOM server uses RPC which, by the way, is another way to share data between processes, even on other computers. However, you have to learn to use the MIDL compiler, and write .IDL files to use it. Using RPC would allow you to use any parameter for your functions, contrary to DCOM. You could easily fall into some traps (causing memory access violations, for example) if you are not careful with those parameters, though.

/Stefan
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.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Here is how to use MFC's automatic Radio Button handling in your dialog boxes and forms.  Beginner programmers usually start with a OnClick handler for each radio button and that's just not the right way to go.  MFC has a very cool system for handli…
Introduction: Dialogs (1) modal - maintaining the database. Continuing from the ninth article about sudoku.   You might have heard of modal and modeless dialogs.  Here with this Sudoku application will we use one of each type: a modal dialog …
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
Watch the software video of Kernel Import PST to Office 365 tools which can easily import PST and OST files to Office 365 for bulk mailboxes. The process of migration is simple and user can map source and destination mailboxes and easily import data…

587 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