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ioctl(2) [sunos man page]

ioctl(2)							   System Calls 							  ioctl(2)

NAME
ioctl - control device SYNOPSIS
#include <unistd.h> #include <stropts.h> int ioctl(int fildes, int request, /* arg */ ...); DESCRIPTION
The ioctl() function performs a variety of control functions on devices and STREAMS. For non-STREAMS files, the functions performed by this call are device-specific control functions. The request argument and an optional third argument with varying type are passed to the file designated by fildes and are interpreted by the device driver. For STREAMS files, specific functions are performed by the ioctl() function as described in streamio(7I). The fildes argument is an open file descriptor that refers to a device. The request argument selects the control function to be performed and depends on the device being addressed. The arg argument represents a third argument that has additional information that is needed by this specific device to perform the requested function. The data type of arg depends upon the particular control request, but it is either an int or a pointer to a device-specific data structure. In addition to device-specific and STREAMS functions, generic functions are provided by more than one device driver (for example, the gen- eral terminal interface.) See termio(7I)). RETURN VALUES
Upon successful completion, the value returned depends upon the device control function, but must be a non-negative integer. Otherwise, -1 is returned and errno is set to indicate the error. ERRORS
The ioctl() function will fail for any type of file if: EBADF The fildes argument is not a valid open file descriptor. EINTR A signal was caught during the execution of the ioctl() function. EINVAL The STREAM or multiplexer referenced by fildes is linked (directly or indirectly) downstream from a multiplexer. The ioctl() function will also fail if the device driver detects an error. In this case, the error is passed through ioctl() without change to the caller. A particular driver might not have all of the following error cases. Under the following conditions, requests to device drivers may fail and set errno to indicate the error EFAULT The request argument requires a data transfer to or from a buffer pointed to by arg, but arg points to an illegal address. EINVAL The request or arg argument is not valid for this device. EIO Some physical I/O error has occurred. ENOLINK The fildes argument is on a remote machine and the link to that machine is no longer active. ENOTTY The fildes argument is not associated with a STREAMS device that accepts control functions. ENXIO The request and arg arguments are valid for this device driver, but the service requested can not be performed on this par- ticular subdevice. ENODEV The fildes argument refers to a valid STREAMS device, but the corresponding device driver does not support the ioctl() function. STREAMS errors are described in streamio(7I). ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
attributes(5), standards(5), streamio(7I), termio(7I) SunOS 5.10 15 Feb 1996 ioctl(2)

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ioctl(2)							System Calls Manual							  ioctl(2)

NAME
ioctl - Controls devices SYNOPSIS
#include <stropts.h> int ioctl( int fildes, int request, ... /* arg */); STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: ioctl(): XSH5.0 Refer to the standards(5) reference page for more information about industry standards and associated tags. PARAMETERS
Specifies the file descriptor of the requested device. Specifies the ioctl command to be performed on the device. Specifies parameters for this request. The type of arg is dependent on the specific ioctl() request and device to which the ioctl is targeted. See the appro- priate Section 7 reference page or the documentation accompanying the device for more information. DESCRIPTION
The ioctl() function performs a variety of control functions on devices and STREAMS. For non-STREAMS files, the functions performed by this call are device-specific control functions. The request and arg parameters are passed to the file designated by fildes and are inter- preted by the device driver. This control is occasionally used on non-STREAMS devices, with the basic input/output functions performed through the read() and write() system calls. An ioctl() request has encoded in it whether the parameter is an "in" parameter or "out" parameter, and the size of the arg parameter in bytes. Macros and defines used to specify an ioctl() request are located in the <stropts.h> header file. For STREAMS files, specific functions are performed by the ioctl() function as described in streamio(7). STREAMS errors are described in streamio(7). RETURN VALUES
Upon successful completion, the ioctl() function returns a value other than -1 that depends upon the STREAMS device control function. If an error occurs, a value of -1 is returned and errno is set to indicate the error. ERRORS
The ioctl() function sets errno to the specified values for the following general conditions: The fildes parameter is not a valid open file descriptor. A signal was caught during the ioctl() operation. The STREAM or multiplexer referenced by fildes is linked (directly or indi- rectly) downstream from a multiplexer. If an underlying device driver detects an error, errno may be set to one of the following values: Either the request or arg parameter is not valid. Some physical I/O error has occurred. The fildes parameter is not associated with a STREAMS device that accepts control func- tions. (Defined for Issue 4 Version 2 and higher issues of the XSH specification.) [Tru64 UNIX] The fildes parameter is not associated with a character special device, or the specified request does not apply to the kind of object that the fildes parameter references. The request and arg parameters are valid for this device driver, but the service requested cannot be performed on the particular subdevice. The fildes parameter refers to a valid STREAMS device, but the corresponding device driver does not support the ioctl() function. RELATED INFORMATION
Functions: exec(2), fcntl(2) Files: tty(7), streamio(7) Standards: standards(5) delim off ioctl(2)

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