outb

OUTB(2)                    Linux Programmer's Manual                   OUTB(2)



NAME
       outb, outw, outl, outsb, outsw, outsl - port output
       inb, inw, inl, insb, insw, insl - port input
       outb_p, outw_p, outl_p, inb_p, inw_p, inl_p - paused I/O


DESCRIPTION
       This family of functions is used to do low level port input and output.
       They are primarily designed for internal kernel use, but  can  be  used
       from user space.

       You  compile  with  -O  or -O2 or similar. The functions are defined as
       inline macros, and will not  be  substituted  in  without  optimization
       enabled, causing unresolved references at link time.

       You  use ioperm(2) or alternatively iopl(2) to tell the kernel to allow
       the user space application to access the I/O ports in question. Failure
       to  do this will cause the application to receive a segmentation fault.


CONFORMING TO
       outb and friends are hardware specific. The port  and  value  arguments
       are in the opposite order to most DOS implementations.

SEE ALSO
       ioperm(2), iopl(2)



Linux                             1995-11-29                           OUTB(2)