Socket select() API. [Input/Output]

Data Structures
struct	pj_fd_set_t
Functions
void	PJ_FD_ZERO (pj_fd_set_t *fdsetp)
pj_size_t	PJ_FD_COUNT (const pj_fd_set_t *fdsetp)
void	PJ_FD_SET (pj_sock_t fd, pj_fd_set_t *fdsetp)
void	PJ_FD_CLR (pj_sock_t fd, pj_fd_set_t *fdsetp)
pj_bool_t	PJ_FD_ISSET (pj_sock_t fd, const pj_fd_set_t *fdsetp)
int	pj_sock_select (int n, pj_fd_set_t *readfds, pj_fd_set_t *writefds, pj_fd_set_t *exceptfds, const pj_time_val *timeout)

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Detailed Description

This module provides portable abstraction for select() like API. The abstraction is needed so that it can utilize various event dispatching mechanisms that are available across platforms.

The API is very similar to normal select() usage.

Examples

For some examples on how to use the select API, please see:

• Test: Socket Select()

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Function Documentation

void PJ_FD_CLR	(	pj_sock_t	fd,
		pj_fd_set_t *	fdsetp
	)

Remove the file descriptor fd from the set pointed to by fdsetp. If fd is not a member of this set, there shall be no effect on the set, nor will an error be returned.

Parameters:

	fd	The socket descriptor.
	fdsetp	The descriptor set.

pj_size_t PJ_FD_COUNT

(

const pj_fd_set_t *

fdsetp

)

This is an internal function, application shouldn't use this.

Get the number of descriptors in the set. This is defined in sock_select.c This function will only return the number of sockets set from PJ_FD_SET operation. When the set is modified by other means (such as by select()), the count will not be reflected here.

Parameters:

fdsetp

The descriptor set.

Returns:

Number of descriptors in the set.

pj_bool_t PJ_FD_ISSET	(	pj_sock_t	fd,
		const pj_fd_set_t *	fdsetp
	)

Evaluate to non-zero if the file descriptor fd is a member of the set pointed to by fdsetp, and shall evaluate to zero otherwise.

Parameters:

	fd	The socket descriptor.
	fdsetp	The descriptor set.

Returns:

Nonzero if fd is member of the descriptor set.

void PJ_FD_SET	(	pj_sock_t	fd,
		pj_fd_set_t *	fdsetp
	)

Add the file descriptor fd to the set pointed to by fdsetp. If the file descriptor fd is already in this set, there shall be no effect on the set, nor will an error be returned.

Parameters:

	fd	The socket descriptor.
	fdsetp	The descriptor set.

void PJ_FD_ZERO

(

pj_fd_set_t *

fdsetp

)

Initialize the descriptor set pointed to by fdsetp to the null set.

Parameters:

fdsetp

The descriptor set.

int pj_sock_select	(	int	n,
		pj_fd_set_t *	readfds,
		pj_fd_set_t *	writefds,
		pj_fd_set_t *	exceptfds,
		const pj_time_val *	timeout
	)

This function wait for a number of file descriptors to change status. The behaviour is the same as select() function call which appear in standard BSD socket libraries.

Parameters:

	n	On Unices, this specifies the highest-numbered descriptor in any of the three set, plus 1. On Windows, the value is ignored.
	readfds	Optional pointer to a set of sockets to be checked for readability.
	writefds	Optional pointer to a set of sockets to be checked for writability.
	exceptfds	Optional pointer to a set of sockets to be checked for errors.
	timeout	Maximum time for select to wait, or null for blocking operations.

Returns:

The total number of socket handles that are ready, or zero if the time limit expired, or -1 if an error occurred.