Re: RFC: Add named errors and messages to remote protocol

[Jim Blandy <jimb at codesourcery dot com>]

Eli Zaretskii <eliz@gnu.org> writes:
>> From: Jim Blandy <jimb@codesourcery.com>
>> Date: Wed, 04 Jul 2007 00:08:08 -0700
>> 
>> A stub is required to support the @samp{g}, @samp{G}, @samp{m}, @samp{M},
>> @samp{c}, and @samp{s} @var{command}s.  All other @var{command}s are
>> optional.
>> on that response (but see also @ref{qSupported}).
>
> Something is wrong here.

Sorry.  I tried to produce this text from a patch.  I should have
simply copied it from the patched manual:


@node Standard Replies
@section Standard Replies

The remote protocol specifies a few standard replies.  All commands
support these, except as noted in the individual command descriptions.

@table @samp

@item
@cindex empty response, for unsupported packets
@cindex unsupported packets, empty response for
For any @var{command} not supported by the stub, an empty response
(@samp{$#00}) should be returned.  That way it is possible to extend the
protocol.  A newer @value{GDBN} can tell if a packet is supported based
on that response (but see also @ref{qSupported}).

@item E @var{xx}
An error has occurred; @var{xx} is a two-digit hexadecimal error
number.  In almost all cases, the protocol does not specify the
meaning of the error numbers; GDB usually ignores the numbers, or
displays them to the user without further interpretation.

@item E.@var{name}@r{[}.@var{message}@r{]}
An error has occurred; @var{name} is the name of the error.  The name
may contain letters, numbers, and @samp{-} characters.  If present,
@var{message} is an error message, encoded using the escaped eight-bit
conventions for binary data described above.

Except as noted, named errors may only be returned to commands
documented to expect them; this ensures that older stubs can interact
with newer versions of @value{GDBN}, even when interpretations for
named errors have been added to the protocol.

The protocol uses the following error names:

@table @samp

@item fatal
A fatal error has occurred; the stub will be unable to interact
further with @value{GDBN}.  Fatal errors should always include a
message explaining their cause.

Any command may return this error.

@item memtype
The memory addressed is of the wrong type for the given command.  For
example, a @samp{vFlashWrite} command applied to non-flash memory
elicits an @samp{E.memtype} error response.

@end table
@end table