CODEWITHSUNDEEP
winapiunixmemory-managementportability
Steve Schnepp
Steve Schnepp

Reputation: 4680

What is fadvise/madvise equivalent on windows?

On UNIX, I can, for example, tell the OS that the mapping will be needed in the future with posix_fadvise(POSIX_FADV_WILLNEED). It will then read-ahead the data if it feels so.

How to tell the access intend to Windows ?

Upvotes: 13

Views: 6069

Answers (3)

Steve Schnepp
Steve Schnepp

Reputation: 4680

Actually, as Anders mostly suggested, there is no such method in the memory management functions available in Windows 7 and earlier.

2 different ways exists to do something similar :

  • Read the data asynchronously with ReadFileEx. The data might then still be in the file cache when needed later.
  • Open the file with a streaming hint with the FILE_FLAG_SEQUENTIAL_SCAN attribute of CreateFile. Readahead would then perhaps be automatically done.

Upvotes: 11

Ben Voigt
Ben Voigt

Reputation: 283684

Beginning with Windows 8, there is the PrefetchVirtualMemory function for this purpose.

Upvotes: 14

Anders
Anders

Reputation: 101666

You can pass FILE_FLAG_RANDOM_ACCESS or FILE_FLAG_SEQUENTIAL_SCAN to CreateFile()

Upvotes: 5

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