XSGIvcSendMonitorCommand(3)XSGIvcSendMonitorCommand(3)
NAME
XSGIvcSendMonitorCommand, XSGIvcSendMonitorQuery,
XSGIvcQueryMonitorBaseProtocol,
XSGIvcInitMonitorBaseProtocol - Monitor control
SYNOPSIS
#include <X11/extensions/XSGIvc.h>
void XSGIvcSendMonitorCommand(Display *display,
int screen,
int channel,
const char *monitorCommand,
int commandLength)
Status XSGIvcSendMonitorQuery(Display *display,
int screen,
int channel,
const char *monitorCommand,
int commandLength,
char **monitorResponse,
int *responseLength)
int XSGIvcQueryMonitorBaseProtocol(Display *display,
int screen,
int channel)
void XSGIvcInitMonitorBaseProtocol(Display *display,
int screen,
int channel)
PARAMETERS
display Specifies the connection to the X server.
screen Specifies the screen of the X server.
channel Specifies the channel number.
monitorCommand The command to be sent to the monitor. The
command sequence must be a valid command
packet that will be sent unprocessed to the
monitor connected to channel.
commandLength The length, in bytes, of monitorCommand.
monitorResponse
Returns a pointer to a buffer containing the
response returned from the monitor. This
response will be returned unprocessed.
responseLength The length, in bytes, of monitorResponse.
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XSGIvcSendMonitorCommand(3)XSGIvcSendMonitorCommand(3)
DESCRIPTION
These functions allow an application program to communicate
with a monitor that has the capability to send and receive
such commands. Client programs are responsible for
composing monitor commands and for parsing the result; the X
server simply transports strings between the client and
monitor.
This function is intended for server-to-monitor
communications. Servers do not guarantee that other devices
connected to the bus will function properly, nor will the
bus connecting a monitor always be active; spontaneous
messages from monitors or other devices can be ignored.
Functions
XSGIvcSendMonitorCommand sends a command - for which no
response is expected - to the monitor of the specified
channel.
If a response is expected, use XSGIvcSendMonitorQuery which
sends a command to the monitor of the specified channel and
waits for a response before continuing. The response is
placed in a buffer whose address is returned in
monitorResponse. The client is responsible for calling
XFree on the memory allocated by the library.
The XSGIvcInitMonitorBaseProtocol function must be called to
initialize the protocol the server is going to use to
communicate with the monitor before any commands or queries
are sent to the monitor. This function reinitializes the
monitor protocol each time it is called, and may be called
at any time. XSGIvcQueryMonitorBaseProtocol may be called to
find out if the protocol has already been initialized (see
below).
The XSGIvcQueryMonitorBaseProtocol function returns a
description of the protocol the X-Server will use to
communicate with the monitor. The following are defined:
XSGIVC_MBPUninitialized
The protocol between the server and
the monitor has not yet been
initialized. Implies that the client
must first call
XSGIvcInitMonitorBaseProtocol in order
to get a valid response.
XSGIVC_MBPNone The server or monitor does not support
monitor commands on this channel.
XSGIVC_MBPAccessBus The server will use ACCESS.bus
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XSGIvcSendMonitorCommand(3)XSGIvcSendMonitorCommand(3)
communications protocol. The content
of message buffers referenced by
monitorCommand and monitorResponse
begin with ACCESS.bus primary opcode.
During its initialization, the server
will switch connected monitors from
VESA DDC1/2AB to ACCESS.bus
communications mode.
EVENTS
No events.
RETURNED VALUE
A BadAccess error indicates a breakdown in the monitor
protocol, and that the client must call
XSGIvcInitMonitorBaseProtocol in order to re-establish
communications with the monitor. In addition, a BadAccess
error will result from a send monitor command or query call
when XSGIvcQueryMonitorBaseProtocol has returned
XSGIVC_MBPNone.
For XSGIvcQueryMonitorBaseProtocol, see the discussion in
DESCRIPTION.
SEE ALSO
XSGIvc
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