gwpoll.h File Reference

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Data Structures
struct	pollfd

Macros
#define	POLLIN   1 /* Reading will not block */
#define	POLLPRI   2 /* Urgent data available for reading */
#define	POLLOUT   4 /* Writing will not block */
#define	POLLERR   8 /* Error condition */
#define	POLLHUP   16 /* Hung up: fd was closed by other side */
#define	POLLNVAL   32 /* Invalid: fd not open or not valid */
#define	POLL_NOTIMEOUT   (-1)
#define	poll(fdarray, numfds, timeout)   gw_poll(fdarray, numfds, timeout)

Functions
int	gw_poll (struct pollfd *fdarray, unsigned int numfds, int timeout)

Macro Definition Documentation

poll

#define poll	(		fdarray,
			numfds,
			timeout
	)		gw_poll(fdarray, numfds, timeout)

Definition at line 104 of file gwpoll.h.

Referenced by gwthread_poll(), gwthread_pollfd(), and gwthread_sleep().

POLL_NOTIMEOUT

#define POLL_NOTIMEOUT   (-1)

Definition at line 100 of file gwpoll.h.

Referenced by gwthread_poll(), gwthread_pollfd(), and gwthread_sleep().

POLLERR

#define POLLERR   8 /* Error condition */

Definition at line 96 of file gwpoll.h.

Referenced by conn_flush(), conn_wait(), poll_callback(), and poller().

POLLHUP

#define POLLHUP   16 /* Hung up: fd was closed by other side */

Definition at line 97 of file gwpoll.h.

Referenced by conn_flush(), conn_wait(), and poll_callback().

POLLIN

#define POLLIN   1 /* Reading will not block */

Definition at line 91 of file gwpoll.h.

Referenced by accept_thread(), cgw_listener(), cgw_wait_command(), conn_register_real(), conn_wait(), emi2_listener(), fake_listener(), gw_accept(), gw_poll(), gwthread_poll(), gwthread_pollfd(), gwthread_sleep(), poll_callback(), server_thread(), unlocked_register_pollin(), and wait_for_connections().

POLLNVAL

#define POLLNVAL   32 /* Invalid: fd not open or not valid */

Definition at line 98 of file gwpoll.h.

Referenced by conn_flush(), conn_wait(), and gw_poll().

POLLOUT

#define POLLOUT   4 /* Writing will not block */

Definition at line 93 of file gwpoll.h.

Referenced by conn_flush(), conn_register_real(), conn_wait(), gw_poll(), poll_callback(), and unlocked_register_pollout().

POLLPRI

#define POLLPRI   2 /* Urgent data available for reading */

Definition at line 92 of file gwpoll.h.

Referenced by gw_poll().

Function Documentation

gw_poll()

int gw_poll	(	struct pollfd *	fdarray,
		unsigned int	numfds,
		int	timeout
	)

Definition at line 67 of file gwpoll.c.

References pollfd::events, pollfd::fd, POLLIN, POLLNVAL, POLLOUT, POLLPRI, and pollfd::revents.

{
    struct timeval tv, *tvp;
    unsigned int i;
    int maxfd;
    fd_set readfds, *rfdp;
    fd_set writefds, *wfdp;
    fd_set exceptfds, *xfdp;
    int ret;
    int result;

    FD_ZERO(&readfds);
    FD_ZERO(&writefds);
    FD_ZERO(&exceptfds);
    maxfd = -1;
    /* These are the pointers we will pass to select().  We use them because
     * we may want to pass NULL for some of them. */
    tvp = NULL;
    rfdp = NULL;
    wfdp = NULL;
    xfdp = NULL;

    /* Deal with timeout.  We get it in milliseconds.  If it's negative,
     * block indefinitely, which we do in select() by passing a NULL
     * timeval pointer. */
    if (timeout >= 0) {
        tv.tv_sec = timeout / 1000;
        tv.tv_usec = (timeout % 1000) * 1000;
        tvp = &tv;
    }

    /* Deal with fdarray, and convert it to the three fd_sets used by select. */
    for (i = 0; i < numfds; i++) {
        int fd = fdarray[i].fd;
        int events = fdarray[i].events;
        if (fd < 0)
            continue;
        if (events & POLLIN) {
            FD_SET(fd, &readfds);
            rfdp = &readfds;
    }
        if (events & POLLOUT) {
            FD_SET(fd, &writefds);
            wfdp = &writefds;
    }
        if (events & POLLPRI) {
            FD_SET(fd, &exceptfds);
            xfdp = &exceptfds;
    }
        if (fd > maxfd && events & (POLLIN | POLLOUT | POLLPRI))
        maxfd = fd;
    }

    ret = select(maxfd + 1, rfdp, wfdp, xfdp, tvp);
    if (ret < 0)
        return ret;

    /* Move the returned data from the fd sets to the revents fields
     * in fdarray.  We can't detect POLLNVAL except for obviously
     * invalid fd's, and detecting POLLHUP or POLLERR would require
     * an extra read() call per fd which is too expensive. */
    result = 0;
    for (i = 0; i < numfds; i++) {
        if (fdarray[i].fd < 0) {
        fdarray[i].revents = POLLNVAL;
            continue;
        }
        fdarray[i].revents = 0;
        if (rfdp && FD_ISSET(fdarray[i].fd, &readfds))
        fdarray[i].revents |= POLLIN;
        if (wfdp && FD_ISSET(fdarray[i].fd, &writefds))
        fdarray[i].revents |= POLLOUT;
        if (xfdp && FD_ISSET(fdarray[i].fd, &exceptfds))
        fdarray[i].revents |= POLLPRI;
    if (fdarray[i].revents != 0)
        result++;
    }

    return result;
}