NAME

control − device independent control routine

SYNOPSIS

int control(dev, function, arg1, arg2)

int dev;
int function;
int arg1, arg2;

DESCRIPTION

Control is the mechanism used to send control information to devices and device drivers, or to interrogate their status.  (Data normally flows through GETC(2), PUTC(2), READ(2), and WRITE(2).) 

Control returns SYSERR if dev is incorrect or if the function cannot be performed.  The values returned otherwise are device dependent.  For example, there is a control function for "tty" devices that returns the number of characters waiting in the input queue. 

SEE ALSO

close(2), getc(2), open(2), putc(2), read(2), seek(2), write(2)

December 01, 1986  —  Xinu Programmer’s Manual