Visible to Intel only — GUID: wxh1653012381793
Ixiasoft
Visible to Intel only — GUID: wxh1653012381793
Ixiasoft
12.1.1.79. ioctl()
Prototype
int ioctl (int fd, int req, void* arg)Commonly Called By
C/C++ programsDevice drivers
Thread-safe
See description.Available from ISR
No.Include
<sys/ioctl.h>Description
The ioctl() function allows application code to manipulate the I/O capabilities of a device driver in driver-specific ways. This function is equivalent to the standard UNIX ioctl() function. The input argument fd is an open file descriptor for the device to manipulate, req is an enumeration defining the operation request, and the interpretation of arg is request specific.For file subsystems, ioctl() is wrapper function that passes control directly to the appropriate device driver’s ioctl() function (as registered in the driver’s alt_dev structure).
For devices, ioctl() handles TIOCEXCL and TIOCNXCL requests internally, without calling the device driver. These requests lock and release a device for exclusive access. For requests other than TIOCEXCL and TIOCNXCL, ioctl() passes control to the device driver’s ioctl() function.
Calls to ioctl() are thread-safe only if the implementation of ioctl() provided by the driver that is manipulated is thread-safe.
Valid values for the fd parameter are: stdout, stdin, and stderr, or any value returned from a call to open().