XvQueryAdaptors(3)

Name
XvQueryAdaptors - return adaptor information for a screen

Syntax
#include <X11/extensions/Xvlib.h>

XvQueryAdaptors(dpy, win, p_num_adaptors, pp_adaptor_info)

Display *dpy;
Drawable draw;
int *p_num_adaptors;
XvAdaptorInfo **pp_adaptor_info;

Arguments

dpy Specifies the display screen on which the Xv Server is to accept requests from Xv clients. If the display option is not specified, Xv uses the display screen specified by your DISPLAY environment variable. The display option has the format hostname:number. Using two colons (::) instead of one (:) indicates that DECnet is to be used for transport.

draw
    Specifies a drawable of the screen for which the adaptor information is desired.

p_num_adaptors
    A pointer to where the numer of adaptors for the specified screen is returned.

pp_adaptor_info
    A pointer to where the list of returned adaptor information is returned.

Description
XvQueryAdaptors(3) returns an video adaptor information for the screen of the specified drawable. The XvAdaptorInfo structure has the following organization:
         typedef struct {
           XvPortID base_id;
           unsigned long num_ports;
           char type;
           char *name;
           unsigned long num_formats;
           XvFormat *formats;
           unsigned long num_adaptors;
         } XvAdaptorInfo;

base_id
    The resource ID of the first adaptor port.

num_ports
    The number of ports supported by the adaptor.

type
    A bit mask with the value XvInputMask asserted if the adaptor supports video input, and value XvOutputMask asserted if the adaptor supports video output.

name
    A vendor specific name that identifies the adaptor.

num_formats
    The number of depth/visual id formats supported by the adaptor.

formats
    A pointer to an array of XvFormat structures.

The XvFormat structure has the following organization:
         typedef struct {
           char depth;
           unsigned long visual_id;
         } XvFormat;

depth
    A drawable depth supported by the adaptor.

visual_id
    A visual-id supported for the given depth by the adaptor.

Returned Values

[Success]
    Returned if XvQueryAdaptors(3) completed successfully.

[XvBadExtension]
    Returned if the Xv extension is unavailable.

[XvBadAlloc]
    Returned if XvQueryAdaptors(3) failed to allocate memory to process the request.

Diagnostics

[Drawable]
    Returned if the requested drawable does not exist.

See Also
XvFreeAdaptorInfo(3)