[PATCH] Add FAQ 4.46. How do I fix find_fast_cwd warnings?

Ken Brown kbrown@cornell.edu
Sun Nov 12 23:02:00 GMT 2017

On 11/12/2017 4:27 PM, Brian Inglis wrote:
> +    <para>Some ancient Cygwin releases asked users to report problems that were
> +      difficult to diagnose to the mailing list with the message:</para>
> +
> +    <screen>find_fast_cwd: WARNING: Couldn't compute FAST_CWD pointer. Please report
> +    this problem to the public mailing listcygwin@cygwin.com</screen>
> +
> +    <para>These problems were fixed long ago in updated Cygwin releases.</para>

The wording of the warning message was changed 3 years ago, in commit 
0793492.  I'm not sure that qualifies as ancient.  I also don't think 
it's accurate to refer to the problem as "difficult to diagnose" or to 
say that the problems "were fixed long ago".

The issue (Corinna will correct me if I'm wrong) is simply that new 
releases of Windows sometimes require changes in how Cygwin finds the 
fast_cwd pointer.  So users of old versions of Cygwin on new versions of 
Windows might have problems, and this can certainly happen again in the 
future.  But the FAQ doesn't need to go into that.  Why not just say 
what the warning currently says (see path.cc:find_fast_cwd()):

"This typically occurs if you're using an older Cygwin version on a 
newer Windows.  Please update to the latest available Cygwin version 
from https://cygwin.com/.  If the problem persists, please see 

You can also add your sentence about contacting the vendor who provided 
the old Cygwin release.


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