This function performs the function FUNCTION using the system function ioctl( ), using SCALAR to set or receive information when appropriate. The available values for FUNCTION are completely system independent. You should refer to your ioctl.h C header file, if you have one available, for suitable values.
Following is the simple syntax for this function −
ioctl FILEHANDLE, FUNCTION, SCALAR
This function returns undef on failure otherwise 0 but true if the return value from the ioctl( )is 0.