media ioctl()
&manvol;

# media-ioctl

Control a media device

          #include <sys/ioctl.h>

    	int ioctl
    	int fd
    	int request
    	void *argp

## Arguments

`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.

## 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 .

&return-value;

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.