media ioctl() &manvol; media-ioctl Control a media device #include <sys/ioctl.h> int ioctl int fd int request void *argp fd &fd; 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. 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 . ioctl() returns 0 on success. On failure, -1 is returned, and the errno variable is set appropriately. Generic error codes are listed below, and 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. EBADF fd is not a valid open file descriptor. EFAULT argp references an inaccessible memory area. EINVAL The request or the data pointed to by argp is not valid. This is a very common error code, see the individual ioctl requests listed in for actual causes. ENOMEM Insufficient kernel memory was available to complete the request. ENOTTY fd is not associated with a character special device.