The Problem (Q-score 15, ranked #2nd of 32 in the Word VBA archive)
The scenario as originally posted in 2011
I have some old Microsoft Word files (probably Word 97) lying around here and noticed that the standard Unix file utility identifies such files as “CDF”. It is actually more precise, dumping detailed meta data, for example:
CDF V2 Document,
Little Endian,
Os: Windows,
Version 4.0,
Code page: 1252,
Title: ...,
Author: ...,
Template: Normal.dot,
Last Saved By: ...,
Revision Number: 1,
Name of Creating Application: Microsoft Word 8.0,
Create Time/Date: ...,
Last Saved Time/Date: ...,
Number of Pages: 1,
Number of Words: 95,
Number of Characters: 542,
Security: 0
What does that CDF stand for? Is that kind of a general container format, like RIFF for media files? I can’t find anything useful on the web. “Channel Definition Format” and “Compound Document Format” are clearly not meant, as those Microsoft Word files are completely binary. For Common Data Format I can’t find a connection. I tried to find something in the sourcecode of the file util (in the version which comes with FreeBSD), but I could only find out that it has a dedicated readcdf.c which deals with this format.
Why community consensus is tight on this one
Across 32 Word VBA entries in the archive, the accepted answer here holds elite answer (top 10 %%) status — meaning voters are unusually aligned on the right fix.
The Verified Solution — elite answer (top 10 %%) (+15)
Advisory answer — community consensus with reference links
Note: the verified answer below is a reference / advisory response rather than a copy-ready snippet.
Compound Documents format is related to OLE/COM. It refers to linking and embedding objects, for example, Excel charts in Word documents.
See the historical (pre-XML) document specifications for MS Office, and the specific file format description is “Windows Compound Binary File Format Specification”.
When to Use It — vintage (14+ years old, pre-2013)
A top-10 Word VBA pattern — why it still holds up
Ranks #2nd of 32 in the Word VBA archive. The only pattern ranked immediately above it is “Version Control for word documents” — compare both if you’re choosing between approaches.
What changed between 2011 and 2026
The answer is 15 years old. The Word VBA object model has been stable across Office 2013, 2016, 2019, 2021, 365, and 2024/2026 LTSC, so the pattern still compiles. Changes that might affect you: 64-bit API declarations (use PtrSafe), blocked macros in downloaded files (Mark-of-the-Web), and the shift toward Office Scripts for web-first workflows.