💾 Archived View for gmi.noulin.net › man › man2 › outl.2.gmi captured on 2024-08-31 at 13:39:47. Gemini links have been rewritten to link to archived content

View Raw

More Information

⬅️ Previous capture (2023-09-08)

-=-=-=-=-=-=-

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

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

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,
                  unsigned long count);
       void insw(unsigned short port, void *addr,
                  unsigned long count);
       void insl(unsigned short port, void *addr,
                  unsigned long count);
       void outsb(unsigned short port, const void *addr,
                  unsigned long count);
       void outsw(unsigned short port, const void *addr,
                  unsigned long count);
       void outsl(unsigned short port, const void *addr,
                  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 func‐
       tions 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 un‐
       resolved 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 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)

Linux                                                                          2020-11-01                                                                        OUTB(2)