select.h File Reference

Bitfield expansions for ast_select. More...

#include <sys/time.h>
#include <sys/select.h>
#include <errno.h>
#include "asterisk/compat.h"

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Data Structures
struct	ast_fdset

Macros
#define	_bitsize(a)   (sizeof(a) * 8)
#define	ast_FDMAX   32768
#define	FD_SET(fd, fds)
#define	FD_ZERO(a)

Functions
static int	ast_select (int nfds, ast_fdset *rfds, ast_fdset *wfds, ast_fdset *efds, struct timeval *tvp)
	Waits for activity on a group of channels.

Variables
unsigned int	ast_FD_SETSIZE

Detailed Description

Bitfield expansions for ast_select.

Definition in file select.h.

Macro Definition Documentation

_bitsize

#define _bitsize

(

a

)

(sizeof(a) * 8)

Definition at line 46 of file select.h.

ast_FDMAX

#define ast_FDMAX   32768

Definition at line 41 of file select.h.

FD_SET

#define FD_SET	(		fd,
			fds
	)

Definition at line 58 of file select.h.

       { \
        TYPEOF_FD_SET_FDS_BITS *bytes = (TYPEOF_FD_SET_FDS_BITS *) fds; \
        if (fd < ast_FDMAX) { \
            bytes[fd / _bitsize(*bytes)] |= ((TYPEOF_FD_SET_FDS_BITS) 1) << (fd % _bitsize(*bytes)); \
        } else { \
            fprintf(stderr, "FD %d exceeds the maximum size of ast_fdset!\n", fd); \
        } \
    } while (0)

FD_ZERO

#define FD_ZERO

(

a

)

Definition at line 49 of file select.h.

       { \
        TYPEOF_FD_SET_FDS_BITS *bytes = (TYPEOF_FD_SET_FDS_BITS *) a; \
        int i; \
        for (i = 0; i < ast_FDMAX / _bitsize(TYPEOF_FD_SET_FDS_BITS); i++) { \
            bytes[i] = 0; \
        } \
    } while (0)

Function Documentation

ast_select()

static int ast_select ( int  nfds, ast_fdset *  rfds, ast_fdset *  wfds, ast_fdset *  efds, struct timeval *  tvp  )

inlinestatic

Waits for activity on a group of channels.

Parameters

nfds	the maximum number of file descriptors in the sets
rfds	file descriptors to check for read availability
wfds	file descriptors to check for write availability
efds	file descriptors to check for exceptions (OOB data)
tvp	timeout while waiting for events This is the same as a standard select(), except it guarantees the behaviour where the passed struct timeval is updated with how much time was not slept while waiting for the specified events

Definition at line 79 of file select.h.

{
#ifdef __linux__
    return select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, tvp);
#else
    int save_errno = 0;
    if (tvp) {
        struct timeval tv, tvstart, tvend, tvlen;
        int res;
 
        tv = *tvp;
        gettimeofday(&tvstart, NULL);
        res = select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, tvp);
        save_errno = errno;
        gettimeofday(&tvend, NULL);
        timersub(&tvend, &tvstart, &tvlen);
        timersub(&tv, &tvlen, tvp);
        if (tvp->tv_sec < 0 || (tvp->tv_sec == 0 && tvp->tv_usec < 0)) {
            tvp->tv_sec = 0;
            tvp->tv_usec = 0;
        }
        errno = save_errno;
        return res;
    }
    else
        return select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, NULL);
#endif
}

References errno, NULL, and timersub().

Referenced by ast_poll2(), and main().

Variable Documentation

ast_FD_SETSIZE

unsigned int ast_FD_SETSIZE

extern

Definition at line 86 of file poll.c.

Referenced by main().