Provided by: manpages-dev_6.7-2_all bug

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

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <sys/io.h>

       unsigned char inb(unsigned short port);
       unsigned char inb_p(unsigned short port);
       unsigned short inw(unsigned short port);
       unsigned short inw_p(unsigned short port);
       unsigned int inl(unsigned short port);
       unsigned int inl_p(unsigned short port);

       void outb(unsigned char value, unsigned short port);
       void outb_p(unsigned char value, unsigned short port);
       void outw(unsigned short value, unsigned short port);
       void outw_p(unsigned short value, unsigned short port);
       void outl(unsigned int value, unsigned short port);
       void outl_p(unsigned int value, unsigned short port);

       void insb(unsigned short port, void addr[.count],
                  unsigned long count);
       void insw(unsigned short port, void addr[.count],
                  unsigned long count);
       void insl(unsigned short port, void addr[.count],
                  unsigned long count);
       void outsb(unsigned short port, const void addr[.count],
                  unsigned long count);
       void outsw(unsigned short port, const void addr[.count],
                  unsigned long count);
       void outsl(unsigned short port, const void addr[.count],
                  unsigned long count);

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  must 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.

VERSIONS

       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.

STANDARDS

       None.

SEE ALSO

       ioperm(2), iopl(2)

Linux man-pages 6.7                                2023-10-31                                            outb(2)