mime.types: extensions ignored

[Laurent]

Greetings...

I'm facing a problem with the mime.types file. (CUPS 1.1.21rc1, Dec Tru64).
I'm trying to add a filter for pretty-printing C programming files,
and then I'm trying to add a specific recognition line in the
mime.types file, based only on the file extension, like :

  text/x-c			c
  text/plain			txt printable(0,1024)

It does not work. The "text/plain" format is choosen.

In fact, every extension rule seems to be ignored.
For example, if the line for text files is changed to :

  text/plain			txt

the file format is not recognized ("unable to print file: client-error-document-format-not-supported").
Same for pdf files, etc.
It's only the other rules (based on what's inside the file) that actually
do the format recognition.

What's wrong ?
Am I missing something ?

--
Laurent