Linker Support for Delay-Loaded DLLs
The MSVC linker now supports the delayed loading of DLLs. This relieves you of the need to use the Windows SDK functions LoadLibrary and GetProcAddress to implement DLL delayed loading.
Before Visual C++ 6.0, the only way to load a DLL at run time was by using LoadLibrary and GetProcAddress; the operating system would load the DLL when the executable or DLL using it was loaded.
Beginning with Visual C++ 6.0, when implicitly linking with a DLL, the linker provides options to delay load the DLL until the program calls a function in that DLL.
An application can delay load a DLL using the /DELAYLOAD (Delay Load Import) linker option with a helper function (default implementation provided by Visual C++). The helper function will load the DLL at run time by calling LoadLibrary and GetProcAddress for you.
You should consider delay loading a DLL if:
Your program may not call a function in the DLL.
A function in the DLL may not get called until late in your program's execution.
The delayed loading of a DLL can be specified during the build of either a .EXE or .DLL project. A .DLL project that delays the loading of one or more DLLs should not itself call a delay-loaded entry point in Dllmain.
The following topics describe delay loading DLLs: