?
Solved

Unresolved external in BC 5.01

Posted on 1997-02-18
7
Medium Priority
?
249 Views
Last Modified: 2013-12-04
I'm trying to convert a 16-bit dll to 32-bit. The dll uses an ojbect file that I created using MASM 6.11c. I compiled the ASM file and have a new 32-bit .OBJ file. It compiled with no errors. The relevent part of the ASM file follows:

.386
.model flat, stdcall      
.CODE
M250    PROC   NEAR COMMAND:DWORD, L_RESPONSE:DWORD, RET_ERROR:DWORD

In the header file for the dll, I have the following line to define the prototype for M250:

extern "C"
{
  BOOL __stdcall M250(short *command, long *response, short
*errorCode);
}

The TargetExpert options are Platform:Win32 and Target Model: Console.

And the IDE project looks like this:

250dll32 {.dll]
   |
   250dlld [.cpp]
   |
   |--250dll [.h]
   |
   M250_32  [.obj]
   |
   default  [.def]


When I attempt to build the dll. I get the following message

Info :Building...
Info :Compiling C:\Model250\250ewin\version5\32bit\250dlld.cpp
Info :Linking C:\Model250\250ewin\version5\32bit\250dll32.dll
Warn :  Warning: .DEF file heap reserve size < 64K; 1MB default will be used
Warn :  Warning: .DEF file stack reserve size < 64K; 1MB default will be used
Error:  Error: Unresolved external 'M250' referenced from module 250dlld.cpp

What am I doing wrong? The project compiles and runs fine when I built it for 16-bit.
0
Comment
Question by:SeanR
  • 5
  • 2
7 Comments
 
LVL 1

Accepted Solution

by:
chedrick earned 200 total points
ID: 1300026
Drop the NEAR....

Chuck
0
 

Author Comment

by:SeanR
ID: 1300027
I dropped the NEAR. No change, still unresolved external 'M250'.
0
 
LVL 1

Expert Comment

by:chedrick
ID: 1300028
Opps, I answer so many of these sometimes I forget and submit an incomplete answer. Sorry about that {:-)
In Win32 a short is two bytes and a long is four The compiler is trying to resolve a M250 with a short int, a long and another short int as arguments. You function has DWORD,DWORD,DWORD.
Adjust one or the other to match and this should go away (the key work here is should...)
If not, let me know...

Happy linkin'
Chuck
0
Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

 
LVL 1

Expert Comment

by:chedrick
ID: 1300029
Any by the way... pointers (like those your function uses) are 32 bit addresses (that 4 bytes to you and me) so try changing the prototype to
M250(DWORD command, DWORD response, DWORD *errorCode);
and see if it resolves. If so the problem is definitely in the declaration.

0
 
LVL 1

Expert Comment

by:chedrick
ID: 1300030
That declaration should end with DWORD errorCode);
NOT
DWORD *errorCode);
Sorry, too much tube time...

Chuck
0
 
LVL 1

Expert Comment

by:chedrick
ID: 1300031
Sean,
One final suggestion...
I typically use WINAPI (the same as FAR PASCAL) for exported DLL functions in Win32. I don't *think* this is the problem but if the above suggestions fail, try it.

Chuck...
0
 

Author Comment

by:SeanR
ID: 1300032
Sorry for the delay, I've been working on another project.
I have tried the suggestions given above, and I still get "unresolved external 'M250'". Could someone give me an example of a MASM assembly function that takes three arguments by reference in 32-bit code, and the calling declaration in C for Borland C++ 5.01?
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

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

What my article will show is if you ever had to do processing to a listbox without being able to just select all the items in it. My software Visual Studio 2008 crystal report v11 My issue was I wanted to add crystal report to a form and show…
For most people, the WrapPanel seems like a magic when they switch from WinForms to WPF. Most of us will think that the code that is used to write a control like that would be difficult. However, most of the work is done by the WPF engine, and the W…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
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…

615 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