Calling 32-bit DLL's built with Borland C++ from non-BC Apps.
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Due to the way that exception handling was implemented in the Borland C++
product, calling into a 32-bit DLL built with Borland C++ from an application
that was not built with Borland C++ results in a failure (typically a system
exception). Borland will be providing a complete correction to this problem in
the future; however, that involves considerable work and cannot be made
available in a short timeframe.

By this document and the accompanying file c0d32dyn.obj, a solution is provided
that allows calling a DLL compiled with Borland C++ from applications created
with other tools. This solution supports only dynamic binding, which is achieved
by the application calling LoadLibrary at run-time to load the DLL and then
calling GetProcAddress to retrieve the entry points for the functions exported
from the DLL.

This solution does not support static binding. From a C or C++ application,
static binding is achieved by linking import records (either import libraries or
entries in the IMPORTS section of the application's Module Definition File) to
the calling application. Using Delphi 2.0, static binding is achieved using a
declaration such as:

function Foo(parm: Integer): Integer; stdcall; external 'mytools.dll' name 'Foo';

You can use either C++ or Structured Exception Handling in the DLL. For best
results, exceptions should be caught within the scope of the DLL throwing the
exception. If the calling application is built with Borland C++, Delphi or
Microsoft Visual C++, the exception can be caught in the application calling the
DLL. However, Visual Basic does not seem to have an exception handlng syntax.

To create an EH-compatible 32-bit DLL, you just replace the default startup
code, c0d32.obj for 32-bit DLL's, with c0d32dyn.obj and re-link the DLL. Using
command-line tools, the startup code is the first object module specified to
Tlink32. Using the Integrated Development Environment, select Options |
Environment | Project View and check Show run-time nodes. In the project window,
there will now be displayed entries for the startup module and all the libraries
which are automatically linked in depending on your target. Remove the node for
the startup code, c0d32.obj, and add c0d32dyn.obj in its place.

Examples of using this mechanism with Delphi 2.0, Visual Basic 4.0 and Visual
C++ 4.1, can be found in the file DLLMixEx.zip located on the Borland web page
(http://www.borland.com), and on the Borland CompuServe forum (!go BCPP or
BCPPLib, Library 2).