?
Solved

C++-DLL and Delphi 3

Posted on 1998-11-09
1
Medium Priority
?
211 Views
Last Modified: 2010-04-04
Hello,

I've written a DLL in Borland C++ 5.0.  One of the functions is a simple
concatenation function :

char* __stdcall _export StringTest(char* Str1, char* Str2)
{
   char* tmp;

   int l1 = strlen(Str1);
   int l2 = strlen(Str2);

   tmp = (char*) malloc(l1+l2+1);
   strcpy(tmp, Str1);
   strcat(tmp,Str2);
   return tmp;
}

This function works fine, but it has a memory leak : the memory
allocated for tmp is not released.

This function is called from a Delphi 3 application.  Can anyone tell me
how I can release the allocated memory, prefarably from the Delphi
application ?
I've tried freeing the memory just before the return instruction, but it
doesn't work.

Thanks in advance,

Johan

0
Comment
Question by:ppr
1 Comment
 
LVL 1

Accepted Solution

by:
AndersWP earned 600 total points
ID: 1346252
ppr:

To manage memory from both Delphi and Borland C++ (or any other windows programming tool), you should use the WinAPI memory functions. I have written two code snippets in Pascal that shows how to do malloc- and free-like functions using the WinAPI. I trust you can convert to C (or whatever) and add error handling as needed:

Function WinMalloc(aSize: Integer): Pointer;

Begin
  Result:=Pointer(GlobalAlloc(GMEM_FIXED, aSize));
End;

Procedure WinFree(aPointer: Pointer);

Begin
    GlobalFree(GlobalHandle(aPointer));
End;

I hope this will help,

AndersWP
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering 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

Creating an auto free TStringList The TStringList is a basic and frequently used object in Delphi. On many occasions, you may want to create a temporary list, process some items in the list and be done with the list. In such cases, you have to…
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…
Planning to migrate your EDB file(s) to a new or an existing Outlook PST file? This video will guide you how to convert EDB file(s) to PST. Besides this, it also describes, how one can easily search any item(s) from multiple folders or mailboxes…
If you are looking for an automated solution for backup single or multiple Office 365 user mailboxes to Outlook data file, then you can use Kernel Office 365 Backup & Restore tool. Go through the video to check out the steps to backup single or mult…

601 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