Me too, as it were. 
Yesterday I wrote: 
=============
Yes. I don't think you need [P] to understand _rc. 
. whelp _rc 
gets you started. _rc is usually zero, whenever
a command works -- to Stata's satisfaction. If
you see a message like 
unrecognized command:  rgeress
r(199);
r(199) is _rc of 199 in another guise. 
=============
This was wrong. _rc is not just another 
way of reporting return codes. 
Gary Longton and David Kantor gave
the correct answer. 
Nick 
[email protected] 
Michael Blasnik
> 
> You're right.  I have always assumed that the error code 
> shown after an
> error is put in _rc, but it isn't -- you learn something new 
> every day.
> 
> This explains some previous wondering on my part when I find 
> nonzero return
> codes after executing ados that ran without an error. I now 
> realize that
> these were captured inside the ado -- a potentially confusing 
> feature when
> you see a nonzero _rc after running the ado because of a line 
> like -cap
> confirm string var xxx -.
Gary Longton 
 
> > I think that David was actually correct: _rc is a system 
> scalar holding
> the
> > return code from the most recent -capture- command.  See [U]16.4 or
> convince
> > yourself by displaying (-display _rc-) after any erroneous 
> Stata command
> used
> > without -capture-.
> > Though a Stata command may return a variety of error codes, 
> the code will
> not be
> > "captured" in the scalar _rc unless -capture- precedes that command.
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