4.7. ioctl MEDIA_IOC_ENUM_LINKS¶
MEDIA_IOC_ENUM_LINKS - Enumerate all pads and links for a given entity
ioctl(int fd, MEDIA_IOC_ENUM_LINKS, struct media_links_enum *argp)¶
To enumerate pads and/or links for a given entity, applications set the
entity field of a struct
structure and initialize the struct
media_pad_desc and struct
media_link_desc structure arrays pointed by
links fields. They then call the
MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this structure.
pads field is not NULL, the driver fills the
with information about the entity’s pads. The array must have enough
room to store all the entity’s pads. The number of pads can be retrieved
with ioctl MEDIA_IOC_ENUM_ENTITIES.
links field is not NULL, the driver fills the
with information about the entity’s outbound links. The array must have
enough room to store all the entity’s outbound links. The number of
outbound links can be retrieved with ioctl MEDIA_IOC_ENUM_ENTITIES.
Only forward links that originate at one of the entity’s source pads are returned during the enumeration process.
||Entity id, set by the application.|
||Pointer to a pads array allocated by the application. Ignored if NULL.|
||Pointer to a links array allocated by the application. Ignored if NULL.|
||ID of the entity this pad belongs to.|
||0-based pad index.|
||Pad flags, see Media pad flags for more details.|
||Pad at the origin of this link.|
||Pad at the target of this link.|
||Link flags, see Media link flags for more details.|
4.7.5. Return Value¶
On success 0 is returned, on error -1 and the
errno variable is set
appropriately. The generic error codes are described at the
Generic Error Codes chapter.
- The struct
idreferences a non-existing entity.