[PATCH] utf8 flag support on perl lib

dormando dormando at rydia.net
Mon Feb 11 06:21:10 UTC 2008

Tim Bunce wrote:
> On Fri, Jan 11, 2008 at 05:07:10PM +0300, Tomash Brechko wrote:
>> On Fri, Jan 11, 2008 at 16:54:26 +0300, Tomash Brechko wrote:
>>> I'd love to coordinate F_COMPRESSED flag.  C::M and C::M::F currently
>>> use 0x2 (0x1 is F_STORABLE).
>> Thinking more about this, perhaps we may do the following.  As I
>> understand most client libraries do not export flags to the user, but
>> use them internally for bookkeeping.  There are 16/32 (which one?)
> 16 bits, per http://code.sixapart.com/svn/memcached/trunk/server/doc/protocol.txt
>   <flags> is an arbitrary 16-bit unsigned integer (written out in
>   decimal) that the server stores along with the data and sends back
>   when the item is retrieved. Clients may use this as a bit field to
>   store data-specific information; this field is opaque to the server.
>   Note that in memcached 1.2.1 and higher, flags may be 32-bits, instead
>   of 16, but you might want to restrict yourself to 16 bits for
>   compatibility with older versions.
> I wonder why that says "may". Does anyone know?
> If it is now 32-bit then we'd know that the top 16 bits are very
> unlikely to be used at the moment and so we could adopt those
> for "informal standardisation" with little risk.

Flags are passed around as a signed 32-bit value internally. Which is vs
a normal unsigned 32-bit value.

We can change the protocol.txt to say it's 32-bit, but only as of 1.2.1,
and to test it with your client first? Cookies to someone who adds a
test for 32-bit flags into the server :)

I don't suspect there are any issues with the value being signed
internally. Thoughts?


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