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Diffstat (limited to 'usr/src/man/man3vnd/vnd_pollfd.3vnd')
| -rw-r--r-- | usr/src/man/man3vnd/vnd_pollfd.3vnd | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/usr/src/man/man3vnd/vnd_pollfd.3vnd b/usr/src/man/man3vnd/vnd_pollfd.3vnd new file mode 100644 index 0000000000..500d3bac99 --- /dev/null +++ b/usr/src/man/man3vnd/vnd_pollfd.3vnd @@ -0,0 +1,155 @@ +'\" te +.\" +.\" This file and its contents are supplied under the terms of the +.\" Common Development and Distribution License ("CDDL"), version 1.0. +.\" You may only use this file in accordance with the terms of version +.\" 1.0 of the CDDL. +.\" +.\" A full copy of the text of the CDDL should have accompanied this +.\" source. A copy of the CDDL is also available via the Internet at +.\" http://www.illumos.org/license/CDDL. +.\" +.\" +.\" Copyright (c) 2014, Joyent, Inc. All rights reserved. +.\" +.TH VND_POLLFD 3VND "Feb 21, 2014" + +.SH NAME + +vnd_pollfd \- get file descriptor for polling + +.SH SYNOPSIS + +.LP +.nf +cc [ flag... ] file... -lvnd [ library... ] +#include <libvnd.h> + +int vnd_pollfd(vnd_handle_t *vhp); +.fi + +.SH DESCRIPTION +.LP +The vnd_pollfd() function returns an integer id which corresponds to +the file descriptor that represents the underlying device that is +associated with the vnd handle vhp. This file descriptor is suitable +for use with port_associate(3C) and similar polling techniques such as +poll(2). Use of the file descriptor outside of these uses may cause +undocumented behavior from the rest of the library. + +.LP +The file descriptor in question is still managed by libvnd. The caller +must not call close(2) on it. Once vnd_close(3VND) has been called, +any further use of the file descriptor is undefined behavior. + + +.SH RETURN VALUES +.LP +The function returns the integer id of the file descriptor that +corresponds to the underlying vnd device. + +.SH EXAMPLES + +.LP +Example 1 Use event ports for vnd notifications +.sp +.LP +The following sample C program shows how to use the vnd_pollfd +function with event ports to be notified whenever there is data +available to be read. This program assumes that a vnd device named +"vnd0" exists in the current zone. For an example of creating the +device, see Example 1 in vnd_create(3VND). + +.sp +.in +2 +.nf +#include <libvnd.h> +#include <port.h> +#include <sys/types.h> +#include <unistd.h> +#include <fcntl.h> + +int +main(void) +{ + vnd_handle_t *vhp; + vnd_errno_t vnderr; + int port, syserr, vfd, ret; + + port = port_create(); + if (port < 0) { + perror("port_create"); + return (1); + } + + vhp = vnd_open(NULL, "vnd0", &vnderr, &syserr); + if (vhp == NULL) { + if (vnderr == VND_E_SYS) + (void) fprintf(stderr, "failed to open device: %s", + vnd_strsyserror(syserr)); + else + (void) fprintf(stderr, "failed to open device: %s", + vnd_strerror(vnderr)); + (void) close(port); + return (1); + } + + vfd = vnd_pollfd(vhp); + if (fcntl(vfd, F_SETFL, O_NONBLOCK) != 0) { + perror("fcntl"); + vnd_close(vhp); + (void) close(port); + return (1); + } + + if (port_associate(port, PORT_SOURCE_FD, vfd, POLLIN, NULL) != 0) { + perror("port_associate"); + vnd_close(vhp); + (void) close(port); + return (1); + } + + for (;;) { + port_event_t pe; + + + if (port_get(port, &pe, NULL) != 0) { + if (errno == EINTR) + continue; + perror("port_get"); + vnd_close(vhp); + (void) close(port); + return (1); + } + + /* + * Read the data with vnd_frameio_read(3VND) and + * optionally break out of the loop or continue to the + * next iteration and reassociate vfd with the event + * port. + */ + } +} +.fi +.in -2 + +.SH ATTRIBUTES +.sp +.LP +See attributes(5) for descriptions of the following attributes: + +.sp +.TS +box; +c | c +l | l . +ATTRIBUTE TYPE ATTRIBUTE VALUE +_ +Stability Committed +_ +MT-Level See "THREADING" in libvnd(3LIB) +.TE + +.SH SEE ALSO + +close(2), poll(2), port_create(3C), libvnd(3LIB), vnd_close(3VND) |