The module-definition file is an important tool for building DLLs. This file contains information that tells OS/2 the name of the DLL, when to load the DLL, how to manage memory for the DLL, and when to initialize the DLL.

When you create a DLL, the module-definition file must contain a list of all the functions in the DLL that can be called by an application (or by another DLL). You specify these external functions by using an EXPORTS statement in the module-definition file.

You also must tell the Linker where to find the external functions in your application. If the functions are in a DLL, you can use an IMPORTS statement in the module-definition file for the application to tell the Linker where to find the DLL functions. You also can use an import library to tell the Linker where to find your DLL functions.