[nanomsg] Changes to the API
- From: Martin Sustrik <sustrik@xxxxxxxxxx>
- To: nanomsg@xxxxxxxxxxxxx
- Date: Wed, 23 Jan 2013 07:45:36 +0100
Hi all,
I've made some changes to the API.
First of all, using an sp_ prefix which doesn't correlate with the name
of library was confusing. After all, SP is a name of layer in network
stack and thus using sp_send() to send messages is similar to TCP asking
you to use L4_send() to send data.
Thus, I've changed all the prefixes to nn_ or NN_, as approriate.
The only place where SP remains, is the place where it is appropriate,
i.e. when specifying at which level of network stack the socket operates:
s = nn_socket (AF_SP, NN_PUB);
The second change involves how zero-copy buffers are handled. So far the
fucntionality was not implemeted, so changing the API should have
minimal impact.
nn_sendmsg and nn_recvmsg which were originally intended to send/recv
zero-copy buffers were changed to by fully compliant with POSIX. The
support gather/scatter arrays, control information (ancillary data) etc.
Instead, zero-copy buffers can be used with and send/recv function
(nn_send, nn_recv, nn_sendmsg, nn_recvmsg). The way to do it is to
specify NN_MSG instead of length of the buffer. That way the library
knows that the buffer supplied is not a common buffer, rather a one [to
be] allocated by nn_allocmsg. Examples:
void *buf = nn_allocmsg (10, 0);
memset (buf, 0xab, 10);
nn_send (s, buf, NN_MSG, 0);
void *buf;
nn_recv (s, &buf, NN_MSG, 0);
nn_freemsg (buf);
Please, find the changes (as well as actual implementation of zero-copy
buffers) in iovecs branch of the project.
If there are to substantial objections, I will merge the changes to the
mainline shortly.
Martin
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