'\" t
.TH XvGetPortAttribute 3 "libXv 1.0.12" "X Version 11" "libXv Functions"
.SH NAME
XvGetPortAttribute \- return current port attribute value
.\"
.SH SYNOPSIS
.B #include <X11/extensions/Xvlib.h>
.sp
.nf
.BI "int XvGetPortAttribute(Display *" dpy ", XvPortID " port ","
.BI "                       Atom " attribute ", int " p_value ");"
.fi
.SH ARGUMENTS
.\"
.IP \fIdpy\fR 12
Specifies the connection to the X server.
.IP \fIport\fR 12
Specifies the port, associated with the given display, for
which the attribute values are to be returned.
.IP \fIattribute\fR 12
An atom that identifies the attribute to be queried by this
request.  Control atoms are obtained using the XInternAtom
request with a string from the following table.
.IP \fIp_value\fR 12
Pointer to the location where the attribute value is written on
return.
.\"
.SH DESCRIPTION
.\"
.PP
.BR XvGetPortAttribute (3)
returns the current value of the requested
port attribute in the integer pointed to by \fIp_value\fR.
The attribute is identified using an Atom that equates to the attribute name.
The XInternAtom request can be used with one of the strings
below to return a matching Atom.
.PP
.TS
tab(@);
lfHB lfHB lfHB
lfR  lfR  lfR .
_
.PP
.sp 4p
Attribute String@Type@Default
.sp 6p
_
.sp 6p
"XV_ENCODING"@XvEncodingID@Server dependent
"XV_HUE"@[-1000...1000]@0
"XV_SATURATION"@[-1000...1000]@0
"XV_BRIGHTNESS"@[-1000...1000]@0
"XV_CONTRAST"@[-1000...1000]@0
.sp 6p
.TE
.SH RETURN VALUES
.IP [Success] 8
Returned if
.BR XvGetPortAttribute (3)
completed successfully.
.IP [XvBadExtension] 8
Returned if the Xv extension is unavailable.
.IP [XvBadAlloc] 8
Returned if
.BR XvGetPortAttribute (3)
failed to allocate memory to process the request.
.SH DIAGNOSTICS
.IP [XvBadPort] 8
Generated if the requested port does not exist.
.IP [BadMatch] 8
Generated if the requested attribute atom does not specify an attribute
supported by the adaptor.
.SH SEE ALSO
.\"
.BR XvSetPortAttribute (3),
.BR XvPortNotify (3)