NAME¶
outb, outw, outl, outsb, outsw, outsl, inb, inw, inl, insb, insw, insl, outb_p,
outw_p, outl_p, inb_p, inw_p, inl_p - port I/O
DESCRIPTION¶
This family of functions is used to do low-level port input and output. The out*
functions do port output, the in* functions do port input; the b-suffix
functions are byte-width and the w-suffix functions word-width; the _p-suffix
functions pause until the I/O completes.
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.
outb() and friends are hardware-specific. The
value argument is
passed first and the
port argument is passed second, which is the
opposite order from most DOS implementations.
SEE ALSO¶
ioperm(2),
iopl(2)
COLOPHON¶
This page is part of release 3.44 of the Linux
man-pages project. A
description of the project, and information about reporting bugs, can be found
at
http://www.kernel.org/doc/man-pages/.
