Windows® via C/C++, Fifth Edition

Performing Synchronous Device I/O

This section discusses the Windows functions that allow you to perform synchronous device I/O. Keep in mind that a device can be a file, mailslot, pipe, socket, and so on. No matter which device is used, the I/O is performed using the same functions.

Without a doubt, the easiest and most commonly used functions for reading from and writing to devices are ReadFile and WriteFile:

BOOL ReadFile(
   HANDLE      hFile,
   PVOID       pvBuffer,
   DWORD       nNumBytesToRead,
   PDWORD      pdwNumBytes,
   OVERLAPPED* pOverlapped);

BOOL WriteFile(
   HANDLE      hFile,
   CONST VOID  *pvBuffer,
   DWORD       nNumBytesToWrite,
   PDWORD      pdwNumBytes,
   OVERLAPPED* pOverlapped);

The hFile parameter identifies the handle of the device you want to access. When the device is opened, you ...