NAME

     ioperm - set port input/output permissions


SYNOPSIS

     #include <unistd.h>

     int  ioperm(unsigned  long  from,  unsigned  long  num,  int
     turn_on


DESCRIPTION

     Ioperm sets the port access permission bits for the  process
     for  num  bytes starting from port address from to the value
     turn_on.  The use of ioperm requires root privileges.

     Only the first 0x3ff I/O ports  can  be  specified  in  this
     manner.   For  more  ports,  the iopl function must be used.
     Permissions are not inherited on fork, but on exec they are.
     This  is  useful  for giving port access permissions to non-
     privileged tasks.


RETURN VALUE

     On success, zero is returned.  On error, -1 is returned, and
     errno is set appropriately.


CONFORMING TO

     ioperm is Linux specific and should not be used in  programs
     intended to be portable.


SEE ALSO

     iopl(2)