4.3. media ioctl()¶
4.3.1. Name¶
media-ioctl - Control a media device
4.3.3. Arguments¶
fd- File descriptor returned by
open(). request- Media ioctl request code as defined in the media.h header file, for example MEDIA_IOC_SETUP_LINK.
argp- Pointer to a request-specific structure.
4.3.4. Description¶
The ioctl() function manipulates media device
parameters. The argument fd must be an open file descriptor.
The ioctl request code specifies the media function to be called. It
has encoded in it whether the argument is an input, output or read/write
parameter, and the size of the argument argp in bytes.
Macros and structures definitions specifying media ioctl requests and their parameters are located in the media.h header file. All media ioctl requests, their respective function and parameters are specified in Function Reference.
4.3.5. 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.
Request-specific error codes are listed in the individual requests descriptions.
When an ioctl that takes an output or read/write parameter fails, the parameter remains unmodified.