From cc8136896d30890efb24aadc2d3058652aa43d45 Mon Sep 17 00:00:00 2001 From: Martin Sustrik Date: Tue, 22 Sep 2009 10:57:46 +0200 Subject: documentation in zmq.h improved --- bindings/c/zmq.h | 283 ++++++++++++++++++++++++++++++++++++--------------- bindings/cpp/zmq.hpp | 13 --- 2 files changed, 203 insertions(+), 93 deletions(-) (limited to 'bindings') diff --git a/bindings/c/zmq.h b/bindings/c/zmq.h index 797d060..b65a771 100644 --- a/bindings/c/zmq.h +++ b/bindings/c/zmq.h @@ -26,83 +26,35 @@ extern "C" { #include +// Microsoft Visual Studio uses non-standard way to export/import symbols. #if defined ZMQ_BUILDING_LIBZMQ_WITH_MSVC #define ZMQ_EXPORT __declspec(dllexport) +#elif defined _MSC_VER +#define ZMQ_EXPORT __declspec(dllimport) #else #define ZMQ_EXPORT #endif +//////////////////////////////////////////////////////////////////////////////// +// 0MQ message definition. +//////////////////////////////////////////////////////////////////////////////// + // 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 +// Message types. These integers may be stored in 'content' member of the +// message instead of regular pointer to the data. #define ZMQ_DELIMITER 31 #define ZMQ_VSM 32 -// Socket options. -#define ZMQ_HWM 1 // int64_t -#define ZMQ_LWM 2 // int64_t -#define ZMQ_SWAP 3 // int64_t -#define ZMQ_AFFINITY 4 // int64_t -#define ZMQ_IDENTITY 5 // string -#define ZMQ_SUBSCRIBE 6 // string -#define ZMQ_UNSUBSCRIBE 7 // string -#define ZMQ_RATE 8 // int64_t -#define ZMQ_RECOVERY_IVL 9 // int64_t -#define ZMQ_MCAST_LOOP 10 // int64_t - -// 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 - -// Option specifying that the sockets should be pollable. This may be a little -// less efficient that raw non-pollable sockets. -#define ZMQ_POLL 1 - -// 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. +// rather than straighforward malloc/free. Not that 'content' is not a pointer +// to the raw data. Rather it is pointer to zmq::msg_content_t structure +// (see src/msg_content.hpp for its definition). struct zmq_msg_t { void *content; @@ -116,12 +68,15 @@ 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. +// Errors: ENOMEM - message is too big to fit into memory. 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. +// instead 0MQ infrastructure takes ownership of the buffer and +// deallocation function (ffn) will be called once the data are not +// needed anymore. Note that deallocation function prototype is designed +// so that it complies with standard C 'free' function. +typedef void (zmq_free_fn) (void *data); ZMQ_EXPORT int zmq_msg_init_data (struct zmq_msg_t *msg, void *data, size_t size, zmq_free_fn *ffn); @@ -145,35 +100,180 @@ 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); +//////////////////////////////////////////////////////////////////////////////// +// 0MQ infrastructure (a.k.a. context) initialisation & termination. +//////////////////////////////////////////////////////////////////////////////// + +// Flag specifying that the sockets within this context should be pollable. +// This may be a little less efficient that raw non-pollable sockets. +#define ZMQ_POLL 1 // Initialise 0MQ context. 'app_threads' specifies maximal number -// of application threads that can have open sockets at the same time. +// of application threads that can own open sockets at the same time. // 'io_threads' specifies the size of thread pool to handle I/O operations. +// 'flags' argument is a bitmap composed of the flags defined above. // // 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, int flags); -// Deinitialise 0MQ context including all the open sockets. Closing -// sockets after zmq_term has been called will result in undefined behaviour. +// Deinitialise 0MQ context. If there are still open sockets, actual +// deinitialisation of the context is delayed till all the sockets are closed. ZMQ_EXPORT int zmq_term (void *context); -// Open a socket. +//////////////////////////////////////////////////////////////////////////////// +// 0MQ socket definition. +//////////////////////////////////////////////////////////////////////////////// + +// Creating a 0MQ socket. +// ********************** + +// 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 the peers. +#define ZMQ_PUB 1 + +// Socket to subscribe for data. Send function is not implemented for this +// socket type. However, subscribe function can be used to modify the +// message filter (see ZMQ_SUBSCRIBE socket option). +#define ZMQ_SUB 2 + +// Socket to send requests and receive replies. Requests are +// load-balanced among all the peers. This socket type allows +// only an alternated sequence of send's and recv's +#define ZMQ_REQ 3 + +// Socket to receive requests and send replies. This socket type allows +// only an alternated sequence of recv's and send's. Each send is routed to +// the peer that issued the last received request. +#define ZMQ_REP 4 + +// Open a socket. 'type' is one of the socket types defined above. // // 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); +// Destroying the socket. +// ********************** + // 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_); +// Manipulating socket options. +// **************************** + +// Available socket options, their types and default values. + +// High watermark for the message pipes associated with the socket. The water +// mark cannot be exceeded. If the messages don't fit into the pipe emergency +// mechanisms of the particular socket type are used (block, drop etc.) If HWM +// is set to zero, there are no limits for the content of the pipe. +// Type: int64_t Unit: bytes Default: 0 +#define ZMQ_HWM 1 + +// Low watermark makes sense only if high watermark is defined (is non-zero). +// When the emergency state is reached when messages overflow the pipe, the +// emergency lasts till the size of the pipe decreases to low watermark. +// At that point normal state is resumed. +// Type: int64_t Unit: bytes Default: 0 +#define ZMQ_LWM 2 + +// Swap allows the pipe to exceed high watermark. However, the data are written +// to the disk rather than held in the memory. While the high watermark is not +// exceeded there is no disk activity involved though. The value of the option +// defines maximal size of the swap file. +// Type: int64_t Unit: bytes Default: 0 +#define ZMQ_SWAP 3 + +// Affinity defines which threads in the thread pool will be used to handle +// newly created sockets. This way you can dedicate some of the threads (CPUs) +// to a specific work. Value of 0 means no affinity, work is distributed +// fairly among the threads in the thread pool. For non-zero values, the lowest +// bit corresponds to the thread 1, second lowest bit to the thread 2 etc. +// Thus, value of 3 means that from now on newly created sockets will handle +// I/O activity exclusively using threads no. 1 and 2. +// Type: int64_t Unit: N/A (bitmap) Default: 0 +#define ZMQ_AFFINITY 4 + +// Identity of the socket. Identity is important when restarting applications. +// If the socket has no identity, each run of the application is completely +// separated from other runs. However, with identity application reconnects to +// existing infrastructure left by the previous run. Thus it may receive +// messages that were sent in the meantime, it shares pipe limits with the +// previous run etc. +// Type: string Unit: N/A Default: NULL +#define ZMQ_IDENTITY 5 + +// Applicable only to 'sub' socket type. Eastablishes new message filter. +// When 'sub' socket is created all the incoming messages are filtered out. +// This option allows you to subscribe for all messages ("*"), messages with +// specific topic ("x.y.z") and/or messages with specific topic prefix +// ("x.y.*"). Topic is one-byte-size-prefixed string located at +// the very beginning of the message. Multiple filters can be attached to +// a single 'sub' socket. In that case message passes if it matches at least +// one of the filters. +// Type: string Unit: N/A Default: N/A +#define ZMQ_SUBSCRIBE 6 + +// Applicable only to 'sub' socket type. Removes existing message filter. +// The filter specified must match the string passed to ZMQ_SUBSCRIBE options +// exactly. If there were several instances of the same filter created, +// this options removes only one of them, leaving the rest in place +// and functional. +// Type: string Unit: N/A Default: N/A +#define ZMQ_UNSUBSCRIBE 7 + +// This option applies only to multicast transports (pgm & udp). It specifies +// maximal outgoing data rate that an individual sender socket can send. +// Type: uint64_t Unit: kilobits/second Default: 100 +#define ZMQ_RATE 8 + +// This option applies only to multicast transports (pgm & udp). It specifies +// how long can the receiver socket survive when the sender is inaccessible. +// Keep in mind that large recovery intervals at high data rates result in +// very large recovery buffers, meaning that you can easily overload your box +// by setting say 1 minute recovery interval at 1Gb/s rate (requires +// 7GB in-memory buffer). +// Type: uint64_t Unit: seconds Default: 10 +#define ZMQ_RECOVERY_IVL 9 + +// This option applies only to multicast transports (pgm & udp). Value of 1 +// means that the mutlicast packets can be received on the box they were sent +// from. Setting the value to 0 disables the loopback functionality which +// can have negative impact on the performance. if possible, disable +// the loopback in production environments. +// Type: uint64_t Unit: N/A (boolean value) Default: 1 +#define ZMQ_MCAST_LOOP 10 + +// Sets an option on the socket. 'option' argument specifies the option (see +// the option list above). 'optval' is a pointer to the value to set, +// 'optvallen' is the size of the value in bytes. +// +// Errors: EINVAL - unknown option, a value with incorrect length +// or invalid value. +ZMQ_EXPORT int zmq_setsockopt (void *s, int option, const void *optval, + size_t optvallen); + +// Creating connections. +// ********************* + +// Addresses are composed of the name of the protocol to use followed by :// +// and a protocol-specific address. Available protocols: +// +// tcp - the address is composed of IP address and port delimited by colon +// sign (:). The IP address can be a hostname (with 'connect') or +// a network interface name (with 'bind'). Examples "tcp://eth0:5555", +// "tcp://192.168.0.1:20000", "tcp://hq.mycompany.com:80". +// +// pgm & udp - both protocols have same address format. It's network interface +// to use, semicolon (;), multicast group IP address, colon (:) and +// port. Examples: "pgm://eth2;224.0.0.1:8000", +// "udp://192.168.0.111;224.1.1.1:5555". // Bind the socket to a particular address. ZMQ_EXPORT int zmq_bind (void *s, const char *addr); @@ -181,12 +281,25 @@ 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); +// Sending and receiving messages. +// ******************************* + +// The flag specifying that 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 + +// The flag specifying that 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. +#define ZMQ_NOFLUSH 2 + // 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. +// combination the flags described above. // // Errors: EAGAIN - message cannot be sent at the moment (applies only to // non-blocking send). @@ -199,18 +312,28 @@ ZMQ_EXPORT int zmq_send (void *s, struct zmq_msg_t *msg, int flags); 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. +// of the flags described above. // // Errors: EAGAIN - message cannot be received at the moment (applies only to // non-blocking receive). // EFAULT - function isn't supported by particular socket type. ZMQ_EXPORT int zmq_recv (void *s, struct zmq_msg_t *msg, int flags); +//////////////////////////////////////////////////////////////////////////////// +// Helper functions. +//////////////////////////////////////////////////////////////////////////////// + // Helper functions used by perf tests so that they don't have to care // about minutiae of time-related functions on different OS platforms. + +// Starts the stopwatch. Returns the handle to the watch. ZMQ_EXPORT void *zmq_stopwatch_start (); + +// Stops the stopwatch. Returns the number of microseconds elapsed since +// the stopwatch was started. ZMQ_EXPORT unsigned long zmq_stopwatch_stop (void *watch_); + +// Sleeps for specified number of seconds. ZMQ_EXPORT void zmq_sleep (int seconds_); #ifdef __cplusplus diff --git a/bindings/cpp/zmq.hpp b/bindings/cpp/zmq.hpp index a9e63b5..cf7d347 100644 --- a/bindings/cpp/zmq.hpp +++ b/bindings/cpp/zmq.hpp @@ -32,13 +32,6 @@ namespace zmq typedef zmq_free_fn free_fn; - enum message_type_t - { - message_data = 1 << 0, - message_gap = 1 << ZMQ_GAP, - message_delimiter = 1 << ZMQ_DELIMITER - }; - // The class masquerades POSIX-style errno error as a C++ exception. class error_t : public std::exception { @@ -148,12 +141,6 @@ namespace zmq throw error_t (); } - // Returns message type. - inline message_type_t type () - { - return (message_type_t) (1 << zmq_msg_type (this)); - } - // Returns pointer to message's data buffer. inline void *data () { -- cgit v1.2.3