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/*
Copyright (c) 2007-2009 FastMQ Inc.
This file is part of 0MQ.
0MQ is free software; you can redistribute it and/or modify it under
the terms of the Lesser GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
0MQ is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
Lesser GNU General Public License for more details.
You should have received a copy of the Lesser GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ZMQ_H_INCLUDED__
#define __ZMQ_H_INCLUDED__
#ifdef __cplusplus
extern "C" {
#endif
#include <stddef.h>
#if defined ZMQ_BUILDING_LIBZMQ_WITH_MSVC
#define ZMQ_EXPORT __declspec(dllexport)
#else
#define ZMQ_EXPORT
#endif
// Maximal size of "Very Small Message". VSMs are passed by value
// to avoid excessive memory allocation/deallocation.
// If VMSs larger than 255 bytes are required, type of 'vsm_size'
// field in zmq_msg_t structure should be modified accordingly.
#define ZMQ_MAX_VSM_SIZE 30
// Message & notification types.
#define ZMQ_GAP 1
#define ZMQ_DELIMITER 31
#define ZMQ_VSM 32
// Socket options.
#define ZMQ_HWM 1
#define ZMQ_LWM 2
#define ZMQ_SWAP 3
#define ZMQ_MASK 4
#define ZMQ_AFFINITY 5
#define ZMQ_IDENTITY 6
#define ZMQ_SUBSCRIBE 7
#define ZMQ_UNSUBSCRIBE 8
// The operation should be performed in non-blocking mode. I.e. if it cannot
// be processed immediately, error should be returned with errno set to EAGAIN.
#define ZMQ_NOBLOCK 1
// zmq_send should not flush the message downstream immediately. Instead, it
// should batch ZMQ_NOFLUSH messages and send them downstream only if zmq_flush
// is invoked. This is an optimisation for cases where several messages are
// sent in a single business transaction. However, the effect is measurable
// only in extremely high-perf scenarios (million messages a second or so).
// If that's not your case, use standard flushing send instead. See exchange
// example for illustration of ZMQ_NOFLUSH functionality.
#define ZMQ_NOFLUSH 2
// Socket to communicate with a single peer. Allows for a singe connect or a
// single accept. There's no message routing or message filtering involved.
#define ZMQ_P2P 0
// Socket to distribute data. Recv fuction is not implemented for this socket
// type. Messages are distributed in fanout fashion to all peers.
#define ZMQ_PUB 1
// Socket to subscribe to distributed data. Send function is not implemented
// for this socket type. However, subscribe function can be used to modify the
// message filter.
#define ZMQ_SUB 2
// Socket to send requests on and receive replies from. Requests are
// load-balanced among all the peers. This socket type doesn't allow for more
// recv's that there were send's.
#define ZMQ_REQ 3
// Socket to receive requests from and send replies to. This socket type allows
// only an alternated sequence of recv's and send's. Each send is routed to
// the peer that the previous recv delivered message from.
#define ZMQ_REP 4
// Prototype for the message body deallocation functions.
// It is deliberately defined in the way to comply with standard C free.
typedef void (zmq_free_fn) (void *data);
// A message. If 'shared' is true, message content pointed to by 'content'
// is shared, i.e. reference counting is used to manage its lifetime
// rather than straighforward malloc/free. struct zmq_msg_content is
// not declared in the API.
struct zmq_msg_t
{
void *content;
unsigned char shared;
unsigned char vsm_size;
unsigned char vsm_data [ZMQ_MAX_VSM_SIZE];
};
// Initialise an empty message (zero bytes long).
ZMQ_EXPORT int zmq_msg_init (struct zmq_msg_t *msg);
// Initialise a message 'size' bytes long.
//
// Errors: ENOMEM - the size is too large to allocate.
ZMQ_EXPORT int zmq_msg_init_size (struct zmq_msg_t *msg, size_t size);
// Initialise a message from an existing buffer. Message isn't copied,
// instead 0MQ infrastructure take ownership of the buffer and call
// deallocation functio (ffn) once it's not needed anymore.
ZMQ_EXPORT int zmq_msg_init_data (struct zmq_msg_t *msg, void *data,
size_t size, zmq_free_fn *ffn);
// Deallocate the message.
ZMQ_EXPORT int zmq_msg_close (struct zmq_msg_t *msg);
// Move the content of the message from 'src' to 'dest'. The content isn't
// copied, just moved. 'src' is an empty message after the call. Original
// content of 'dest' message is deallocated.
ZMQ_EXPORT int zmq_msg_move (struct zmq_msg_t *dest, struct zmq_msg_t *src);
// Copy the 'src' message to 'dest'. The content isn't copied, instead
// reference count is increased. Don't modify the message data after the
// call as they are shared between two messages. Original content of 'dest'
// message is deallocated.
ZMQ_EXPORT int zmq_msg_copy (struct zmq_msg_t *dest, struct zmq_msg_t *src);
// Returns pointer to message data.
ZMQ_EXPORT void *zmq_msg_data (struct zmq_msg_t *msg);
// Return size of message data (in bytes).
ZMQ_EXPORT size_t zmq_msg_size (struct zmq_msg_t *msg);
// Returns type of the message.
ZMQ_EXPORT int zmq_msg_type (struct zmq_msg_t *msg);
// Initialise 0MQ context. 'app_threads' specifies maximal number
// of application threads that can have open sockets at the same time.
// 'io_threads' specifies the size of thread pool to handle I/O operations.
//
// Errors: EINVAL - one of the arguments is less than zero or there are no
// threads declared at all.
ZMQ_EXPORT void *zmq_init (int app_threads, int io_threads);
// Deinitialise 0MQ context including all the open sockets. Closing
// sockets after zmq_term has been called will result in undefined behaviour.
ZMQ_EXPORT int zmq_term (void *context);
// Open a socket.
//
// Errors: EINVAL - invalid socket type.
// EMFILE - the number of application threads entitled to hold open
// sockets at the same time was exceeded.
ZMQ_EXPORT void *zmq_socket (void *context, int type);
// Close the socket.
ZMQ_EXPORT int zmq_close (void *s);
// Sets an option on the socket.
// EINVAL - unknown option, a value with incorrect length or an invalid value.
ZMQ_EXPORT int zmq_setsockopt (void *s, int option_, const void *optval_,
size_t optvallen_);
// Bind the socket to a particular address.
ZMQ_EXPORT int zmq_bind (void *s, const char *addr);
// Connect the socket to a particular address.
ZMQ_EXPORT int zmq_connect (void *s, const char *addr);
// Send the message 'msg' to the socket 's'. 'flags' argument can be
// combination of following values:
// ZMQ_NOBLOCK - if message cannot be sent, return immediately.
// ZMQ_NOFLUSH - message won't be sent immediately. It'll be sent with either
// subsequent flushing send or explicit call to zmq_flush
// function.
//
// Errors: EAGAIN - message cannot be sent at the moment (applies only to
// non-blocking send).
// ENOTSUP - function isn't supported by particular socket type.
ZMQ_EXPORT int zmq_send (void *s, struct zmq_msg_t *msg, int flags);
// Flush the messages that were send using ZMQ_NOFLUSH flag down the stream.
//
// Errors: ENOTSUP - function isn't supported by particular socket type.
ZMQ_EXPORT int zmq_flush (void *s);
// Send a message from the socket 's'. 'flags' argument can be combination
// of following values:
// ZMQ_NOBLOCK - if message cannot be received, return immediately.
//
// Errors: EAGAIN - message cannot be received at the moment (applies only to
// non-blocking receive).
// ENOTSUP - function isn't supported by particular socket type.
ZMQ_EXPORT int zmq_recv (void *s, struct zmq_msg_t *msg, int flags);
// Helper functions used by perf tests so that they don't have to care
// about minutiae of time-related functions on different OS platforms.
ZMQ_EXPORT void *zmq_stopwatch_start ();
ZMQ_EXPORT unsigned long zmq_stopwatch_stop (void *watch_);
ZMQ_EXPORT void zmq_sleep (int seconds_);
#ifdef __cplusplus
}
#endif
#endif
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