?
Solved

VC++: Weird problem with DLLs

Posted on 1998-02-16
3
Medium Priority
?
193 Views
Last Modified: 2010-04-10
I am trying to figure out how to use other peoples' DLLs in Visual C++, but for some reason I can't seem to load the DLL into memory. I tried the following:

Created a new MFC application (.exe) and added the following code fragment anywhere (for example in CTestView::OnDraw):

HINSTANCE hlib = AfxLoadLibrary("commdlg.dll");
DWORD error = GetLastError();

When I step through this code I see that hlib obtains the value 0 (load failure) and error is equal to 31, which is the error code for General Failure Error. What in the world does a general failure error have to do with loading a DLL? The same result occurs regardless of the DLL I am using (I used commdlg.dll because I know it's a DLL that works). I know that error 31 is originating from AfxLoadLibrary because when I use GetLastError before the call to AfxLoadLibrary I get an error code 0 (success).

What is going on here? I doubt the General Failure error is really what's going on because everything in my OS is working properly (including things that other programs load from the commdlg.dll library). How can I solve this problem?
(Please don't tell me that I can use MFC functions that call commdlg.dll. I've already tried it, and it works. That library name is only an example. The same result happens no matter what DLL I try to load, this is just so that you can try the above code fragment on your computer if you want).

Thanks in advance!

-- Slarti
0
Comment
Question by:Slarti
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
3 Comments
 
LVL 7

Accepted Solution

by:
galkin earned 100 total points
ID: 1182344
I guess you mistake is that you trying to load commdlg.dll which is 16 bit DLL into 32 address space of your EXE. try to load 32 bit version of this DLL comdlg32.dll
0
 
LVL 2

Author Comment

by:Slarti
ID: 1182345
That is probably the problem, then. But I would still like to be able to load 16-bit DLLs into memory. (The problem is that I am trying to interface with a device driver written for Windows 3.1). How can I load a 16-bit DLL?
0
 

Expert Comment

by:donleyp
ID: 1182346
You cannot load a Win16 DLL into a Win32 program's address space. Win32s provided a way for you to do this, but I don't know if it's even supported anymore. Furthermore, Trying to interface to a Win16 device driver in a Win32 environment is extremely dangerous if not impossible. How can you interface to it if the OS won't even load it? Even if you wrote a Win16 program and loaded the driver file directly, Windows would prevent you from accessing the device without going through bona-fide drivers.
0

Featured Post

On Demand Webinar: Networking for the Cloud Era

Ready to improve network connectivity? Watch this webinar to learn how SD-WANs and a one-click instant connect tool can boost provisions, deployment, and management of your cloud connection.

Question has a verified solution.

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

Article by: SunnyDark
This article's goal is to present you with an easy to use XML wrapper for C++ and also present some interesting techniques that you might use with MS C++. The reason I built this class is to ease the pain of using XML files with C++, since there is…
In days of old, returning something by value from a function in C++ was necessarily avoided because it would, invariably, involve one or even two copies of the object being created and potentially costly calls to a copy-constructor and destructor. A…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…
The viewer will learn how to user default arguments when defining functions. This method of defining functions will be contrasted with the non-default-argument of defining functions.

770 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