.TH XvQueryPortAttributes __libmansuffix__ __vendorversion__ "libXv Functions"
.SH NAME
XvQueryPortAttributes \- return list of attributes of a video port
.\"
.SH SYNOPSIS
.B #include <X11/extensions/Xvlib.h>
.sp
.nf
.BI "XvAttribute* XvQueryPortAttributes(Display *" dpy ","
.BI "                 XvPortID " port ",  int *" p_num_attributes ");"
.fi
.SH ARGUMENTS
.\"
.IP \fIdpy\fR 8
Specifies the connection to the X server.
.IP \fIport\fR 8
Specifies the port whose adaptor is to be queried for its list of attributes.
.IP \fIp_num_attributes\fR 8
A pointer to where the number of attributes returned in the array is written.
.\"
.SH DESCRIPTION
.BR XvQueryPortAttributes (__libmansuffix__) returns the number of attributes
and an array of XvAttributes valid for the given port.  The array may be
freed with
.BR XFree (__libmansuffix__).
.SH RETURN VALUES
XvAttribute has the following structure:
.EX

    typedef struct {
      int flags;
      int min_value;
      int max_value;
      char *name;
    } XvAttribute;

.EE
.IP \fIflags\fR 8
May be XvGettable or XvSettable or both OR'd together indicating the
particular attribute is readable, writeable or readable and writeable.
.IP \fImin_value\fR 8
The minimum attribute values which are valid for the driver.
.IP \fI max_value\fR 8
The maximum attribute values which are valid for the driver.
.IP \fIname\fR 8
A string describing the name of the attribute that may be used
to retrieve the Atom for the particular attribute.
.\"
.SH DIAGNOSTICS
.IP [XvBadPort] 8
Generated if the requested port does not exist.
.\"
.SH SEE ALSO
.BR XvGetPortAttribute (__libmansuffix__),
.BR XvSetPortAttribute (__libmansuffix__)