See this streams utility and associated information to further explore the issue.

I've never thought that SummaryInformation was stored anywhere except inside the file, for COM "Compound Document" files specifically including MS Office files. The shell extension simply looks at that.

Meanwhile, I noticed that Windows 2000 allowed a Summary tab on other files as well. I assumed it stored that in an alternate stream, but never looked into it in detail.

So I disagree with your second paragraph. To read SummaryInfo from a Structured Storage file, use the SS-related function for that. (IPropertyStorage, I think). The COM SDK has a page "Structured Storage Serialized Property Set Format". If that interface is a dual (dispatch-enabled), then it's a simple matter to drive with Perl's OLE module and then parse out the individual fields.

The alternate data stream is trivial to read from Perl, once you figure out the correct name. I suppose it uses the same serialized format.

I agree, a Perl module to read/write this information would be awesome! It would figure out which way is being used, and use the proper way to add info to a file that doesn't have it already.

—John

In reply to Re: Win32 Strustured Storage via File - Properties - Summary by John M. Dlugosz
in thread Win32 Strustured Storage via File - Properties - Summary by idnopheq

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