Table of Contentsioctl - control device #include <sys/ioctl.h> int ioctl(int d, int request, ...)
[The "third" argument is traditionally char *argp, and will be so named for this discussion.]
The ioctl function manipulates the underlying device parameters of special files. In particular, many operating characteristics of character special files (e.g. terminals) may be controlled with ioctl requests. The argument d must be an open file descriptor. An ioctl request has encoded in it whether the argument is an in parameter or out parameter, and the size of the argument argp in bytes. Macros and defines used in specifying an ioctl request are located in the file sys/ioctl.h.
On success, zero is returned. On error, -1 is returned, and errno is set appropriately. - EBADF
- d is not a valid descriptor.
- ENOTTY
- d is not associated with a character special device.
- ENOTTY
- The specified request does not apply to the kind of object that the descriptor d references.
- EINVAL
- Request or argp is not valid.
An ioctl function call appeared in Version 7 AT&T UNIX. execve(2), fcntl(2), mt(4), sd(4), tty(4)
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