RE: [RFC PATCH] gdb, rsp: clarify a 0-length memory access

["Aktemur, Tankut Baris" <tankut.baris.aktemur@intel.com>]

On Thursday, March 28, 2024 3:13 PM, Andrew Burgess wrote:
> Tankut Baris Aktemur <tankut.baris.aktemur@intel.com> writes:
> 
> > Currently GDB uses a 0-length write access to probe for the 'X' packet
> > support.  However, it is not clear from the document what a 0-length
> > read or write attempt should do.  Clarify the document that it is
> > an error.  Also update gdbserver's implementation to return an error.
> 
> We're usually pretty conservative about changing existing remote
> protocol behaviour.
> 
> If I understand the current behaviour correctly, we treat the zero
> length access as always succeeding, but you propose to change this to
> always fail.
> 
> What's the motivation for this change?  Does the existing behaviour
> cause some problem?
> 
> Usually, when the docs are ambiguous we update the docs to reflect GDB's
> current behaviour, unless the current behaviour is clearly wrong.
> 
> Thanks,
> Andrew

Hi Andrew,

The background of the submission is the thread linked below, where Tom expressed
his tendency to think that a 0-length access should be an error:

https://sourceware.org/pipermail/gdb-patches/2024-March/207411.html

Thanks
-Baris


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