Microsoft C/C++ provides several new functions to support virtual memory. See Chapter 2 in the Run-Time Library Reference for a list. A list of new functions provided to support Microsoft QuickWin is also in Chapter 2 of that manual.
In addition to the _osmajor, _osminor, _osversion, and _osmode variables, Microsoft C/C++ now provides the _cpumode variable. It returns either _REAL_MODE or _PROTECT_MODE to indicate the mode of the current process.
The new _fatexit and _fonexit functions provide model-independent processing at program termination.
The new library functions _snprintf and _vsnprintf can be used to control the size of a formatted string written to a buffer.
Microsoft C/C++ now provides the ability to bypass the operating system buffers and flush a file directly to disk. The new functions that provide this capability are _commit in IO.H and _dos_commit in DOS.H. The fdopen and fopen functions have new flags to specify either mode. To take advantage of this with applications written prior to Microsoft C, version 7.0, you can link your application with COMMODE.OBJ in your \C700\LIB directory.
See the Run-Time Library Reference for complete information on all these new library functions.