All rights reserved.
Socket Dispatcher is a generic dispatcher library for sockets.
To make use of the functionality the dispatcher need to be initialized using initSocketDispatcher. It is then possible to add sockets to the dispatcher using addSocket and remove using delSocket. To execute the dispatcher function the socketDispatcher function is used. See below for more information on exact usage.
The supported event types are:
Example:
void callback(int fd, int type) {
...
}
int main(int argc, char** argv) {
struct socketDispatcher_t d;
initSocketDispatcher(&d, SELECT, callBackFunction, 1000000);
addSocket(&d, <socket>, DISPATCHER_READ);
while(1) {
socketDispatcher(&d);
}
}
The Socket Dispatcher Library supports a number of different socket event mechanisms available in different operating systems:
The dispatcher is thread safe, which means that the internal data structures is protected so that different threads can not manipulate data at the same time.
This means that during the dispatcher call, no elements can be removed and for select dispatcher not added either. The dispatcher can not be called twice as well. It also means that data can not be added and removed at the same time including two additions and two removes.
Before initSocketDispatcher and after closeSocketDispatcher is called the library have undefined function and is not thread safe. The library also have undefined functionality for unsupported dispatcher types, including those disabled with DISABLE_<type>.
NOTE! This means that deadlocks is possible, especially for infinit timeouts in dispatcher. Avoid infinit timeouts in dispatcher if you have a multithreaded program that rely on the possibility to add and remove sockets to the dispatcher.
When building the library there are a number of ways to define what methods to include depending on the supported operating system or the desired size of the library. The below list show how big the library will be on disk with the following defined.
Measurements on Linux 2.6 and rounded to closest KB:
SELECT POLL EPOLL KQUEUE Dynamic lib Static lib
E E E D 18 KB 15 KB
E E D D 17 KB 13 KB
E D E D 17 KB 14 KB
E D D D 15 KB 12 KB
D E E D 16 KB 13 KB
D E D D 15 KB 11 KB
D D E D 15 KB 11 KB
D D D D 13 KB 9 KB
Measurements on FreeBSD 6.2 and rounded to closest KB:
SELECT POLL EPOLL KQUEUE Dynamic lib Static lib
E E D E 18 KB 14 KB
E E D D 15 KB 12 KB
E D D E 16 KB 13 KB
E D D D 14 KB 11 KB
D E D E 15 KB 12 KB
D E D D 13 KB 10 KB
D D D E 14 KB 11 KB
D D D D 12 KB 8 KB
Data Structures | |
| struct | socketDispatcher_t |
Defines | |
| #define | DISPATCHER_READ 1 |
| #define | DISPATCHER_WRITE 2 |
| #define | DISPATCHER_OTHER 4 |
Typedefs | |
| typedef void(*) | callbackFunction (int, int) |
| typedef int(*) | dispatcherFunction (struct socketDispatcher_t *data) |
Enumerations | |
| enum | dispatcherType { NONE = 0, SELECT = 1, POLL = 2, EPOLL = 3, KQUEUE = 4 } |
Functions | |
| int | socketDispatcher (struct socketDispatcher_t *data) |
| int | initSocketDispatcher (struct socketDispatcher_t *data, enum dispatcherType type, callbackFunction callback, int timeout) |
| void | setSocketDispatcherTimeout (struct socketDispatcher_t *data, int timeout) |
| void | closeSocketDispatcher (struct socketDispatcher_t *data) |
| int | addSocket (struct socketDispatcher_t *data, int socket, int type) |
| void | delSocket (struct socketDispatcher_t *data, int socket) |
| int | getNumberOfSockets (struct socketDispatcher_t *data) |
| #define DISPATCHER_OTHER 4 |
Definition for other events.
OBS! The DISPATCHER_OTHER is not fully tested, and is known to work differently on different type of dispatchers
| #define DISPATCHER_READ 1 |
Definition for read events.
| #define DISPATCHER_WRITE 2 |
Definition for write events.
| typedef void(*) callbackFunction(int, int) |
Callback function definition.
| socket | The socket that is triggered. | |
| type | The type of event caused the trigger. |
| typedef int(*) dispatcherFunction(struct socketDispatcher_t *data) |
Dispatcher function definition.
| data | Data structure for the dispatcher. |
| enum dispatcherType |
| int addSocket | ( | struct socketDispatcher_t * | data, | |
| int | socket, | |||
| int | type | |||
| ) |
Add a socket to the socket dispatcher
| data | Data structure for the dispatcher. | |
| socket | The socket to add | |
| type | Type of events to listen to. |
| void closeSocketDispatcher | ( | struct socketDispatcher_t * | data | ) |
Close dispatcher data strucutres. OBS! This do not close the sockets inside the dispatcher.
| data | Data structure for the dispatcher. |
| void delSocket | ( | struct socketDispatcher_t * | data, | |
| int | socket | |||
| ) |
Remove a socket to the socket dispatcher
| data | Data structure for the dispatcher. | |
| socket | The socket to remove. |
| int getNumberOfSockets | ( | struct socketDispatcher_t * | data | ) |
Get the number of sockets registered in the dispatcher.
| data | Data structure for the dispatcher. |
| int initSocketDispatcher | ( | struct socketDispatcher_t * | data, | |
| enum dispatcherType | type, | |||
| callbackFunction | callback, | |||
| int | timeout | |||
| ) |
Initializer for the dispatcher data structure
| data | Data structure for the dispatcher. | |
| type | Type of dispatcher | |
| callback | A callback function for the dispatcher to call. | |
| timeout | Maximum timeout in micro seconds (< 0 gives an infinite timeout). |
| void setSocketDispatcherTimeout | ( | struct socketDispatcher_t * | data, | |
| int | timeout | |||
| ) |
Set timeout for the dispatcher
| data | Data structure for the dispatcher. | |
| timeout | Maximum timeout in micro seconds (< 0 gives an infinite timeout). |
| int socketDispatcher | ( | struct socketDispatcher_t * | data | ) |
The dispatcher function.
| data | Data structure for the dispatcher. |
1.5.1