Does file add to file with Windows / NTFS?

Question

If I write a simple text log file from several processes, can they overwrite / corrupt each other's records?

(Basically, this question is. Is the append file atomic on UNIX? But for Windows / NTFS.)

Answer 1

Even if the append is atomic (I don't think so), it may not give you the results you need. For example, if the log contains a timestamp, it seems reasonable to expect the addition of later logs after older logs. With concurrency, this guarantee is not fulfilled - if several processes are waiting to write to the same file, any of them can get a write lock, and not just the oldest of them. In this way, logs can be recorded from a sequence.

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Answer 2

. FILE_APPEND_DATA ( WDK). FILE_WRITE_DATA, . FILE_WRITE_DATA, append write (Offset = FILE_WRITE_TO_END_OF_FILE OffsetHigh = -1 WDK).

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Answer 3

MSDN :

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Obviously, you will have to add code to your processes to deal with a situation where they cannot gain exclusive access to the log file.

Answer 4

No, it is not. If you need it, Transactional NTFS on Windows Vista / 7.