7.5. Overlapped I/O

Compatibility Note: The code in this section works properly in Windows 2000 but does not work in Windows 98 because the overlapped concept does not apply to files. See theReadFile and ReadFileExfunctions in the Win32 help file for further information.

The APIs supports an asynchronous form of file access that allows you to start an I/O operation and then proceed with other activities. The technique is referred to as overlapped I/O. This capability exists in Windows for two reasons:

  1. Overlapped I/O lets you create the impression of multi-threading without actually implementing a separate thread. In certain situations, this makes the code more compact, or lets you handle asynchronous file I/O more easily than a second thread ...

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