[nanomsg] Re: weird extra byte in header for IPC
- From: Garrett D'Amore <garrett@xxxxxxxxxx>
- To: "nanomsg@xxxxxxxxxxxxx" <nanomsg@xxxxxxxxxxxxx>
- Date: Tue, 15 Apr 2014 02:01:52 -0700
You can't make that work generally I think.
You'd have to have another region of shared memory established. That feels
like it should be a totally different transport. Indeed with shared memory
you would really like to establish a protocol for placing data in the shared
memory regions.
Anyway nanomsg doesn't have anything like this at present.
Sent from my iPhone
> On Apr 15, 2014, at 1:31 AM, Martin Sustrik <sustrik@xxxxxxxxxx> wrote:
>
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> Hi Garrett,
>
>
>> What was the purpose of the extra byte in the IPC header that
>> precedes the length (for each message). If not for that one
>> difference, the message formats between IPC and TCP/TLS would be
>> identical. I’m having a hard time seeing value in that extra
>> byte.
>>
>> (I noticed this tonight when I was trying to use IPC between C and
>> my Go version, and I discovered that while I tested TCP, apparently
>> I never tested IPC interop… Oops!)
>
> The thing is that with IPC you can actually do zero-copy (store the
> data in shared memory, pass the pointer to the other process). Thus,
> we need a place to signal that the message is not a standard message
> passed via IPC pipe, but rather a descriptor of a block in shared memory.
>
> Martin
>
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