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XvQueryAdaptors - return adaptor information for a screen
#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;
- 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.
XvQueryAdaptors(3X)
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.
- [Success]
- Returns True
if XvQueryAdaptors(3X)
completed successfully.
- [XvBadExtension]
- Returned
if the Xv extension is unavailable.
- [XvBadAlloc]
- Returned if XvQueryAdaptors(3X)
failed to allocate memory to process the request.
- [Drawable]
- Returned
if the requested drawable does not exist.
XvFreeAdaptorInfo(3X)
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