Accessing Win32 Information in the MAPIWIN.H Header File

MAPIWIN.H has three sections. The first section defines how to call an available function by different methods in Win16. Functions included in the first section manage per-instance global variables for dynamic-link libraries (DLLs). They work on the assumption that all of a DLL's per-instance global variables exist in a single block of memory.

The second section specifically defines for the Win16 environment functionality that is generally available in the Win32 environment. This section consists largely of Win32 file input-output functions that are not supported under Win16 but are implemented in MAPI.DLL using MS-DOS calls. Some functions of this type have limitations relative to their Win32 counterparts; the limitations are spelled out in this Appendix. The third section defines conventions that simplify certain common operations.

The following functions have no meaning on Win16, but Microsoft's MAPI implementation defines macros to make it easier to write common code:

CloseMutexHandle

CreateMutex

DeleteCriticalSection

EnterCriticalSection

InitializeCriticalSection

LeaveCriticalSection

ReleaseMutex

WaitforSingleObject