When you compile or assemble an application, the compiler or assembler generates an object module for the code in the application. If you use any functions that are external to your application (their code is in another object module), the compiler or assembler adds an external function reference to your application's object module.

The Linker resolves these external references. If the Linker finds the external function in a library called an import library or in an IMPORTS statement in the application's module-definition file, the code for the external function is in a DLL. To resolve external references to DLLs, the Linker simply adds information to the executable file that tells the loader where to find the DLL code when the application is loaded.