What is the Function entry for DLL in win3.1 ?

BOOL WINAPI DllMain(
HINSTANCE hinstDLL, // handle to DLL module
DWORD fdwReason, // reason for calling function
LPVOID lpReserved ) // reserved

Note that this is optional,DLL can optionally specify an entry-point function. If present, the system calls the entry-point function whenever a process or thread loads or unloads the DLL. It can be used to perform simple initialization and cleanup tasks. For example, it can set up thread local storage when a new thread is created, and clean it up when the thread is terminated.

If you are linking your DLL with the C run-time library, it may provide an entry-point function for you, and allow you to provide a separate initialization function.