File “Date modified” property are not updating while modifying a file without closing it.

• 2 mai 2012 15:12

   

   
  

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  Kimi Chen_, hi,

  We believe this "bug" is affecting us.

  The scenario is as follows:

  1. We have an application opening a file using the WINAPI function CreateFile().
  2. The file is constantly being written to using the WINAPI function WriteFile(), that is, we do not close the file using CloseHandle() after a write operation.
  3. The last modified time, which we _highly_ depend on is not being updated unless we do "something" to the file.  I am not sure what _exactly_ this "something" is but it seems that opening the file causes the last modified time to be updated.

  I would appreciate it, if you were to answer the questions numbered below.

  1. "- in some, but not all, cases a simple "dir filename" is enough to refresh the metadata", what do you mean _exactly_ by "in some, but not all, cases"?  We basically need a guarantee because one of our Customers has been deeply affected by this.
  2. Is there a setting to force Windows to do an IO every time a write operation is done.  That is, it there an OS or file system level setting?  This would require us to make zero code changes to our application – the desired solution.

  We have explored two avenues so far and both do _not_ seem to be using cached value for the latest modified time.  a) GetFileInformationByHandle, and the b) the C-runtime function stat(), reading in the st_mtime.
  
  I found this http://blogs.technet.com/b/asiasupp/archive/2010/12/14/file-date-modified-property-are-not-updating-while-modifying-a-file-without-closing-it.aspx.

  Regards,

  • Mutat de Mike Dos ZhangMicrosoft Contingent Staff 7 mai 2012 10:17 not a Windows Desktop dev question, it almost a System known issue as the MSDN blog mentioned (From:General Windows Desktop Development Issues)
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