Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

(linux section 2)
man page for inw_p

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 int port); unsigned char inb_p(unsigned short int port); unsigned short int inw(unsigned short int port); unsigned short int inw_p(unsigned short int port); unsigned int inl(unsigned short int port); unsigned int inl_p(unsigned short int port); void outb(unsigned char value, unsigned short int port); void outb_p(unsigned char value, unsigned short int port); void outw(unsigned short int value, unsigned short int port); void outw_p(unsigned short int value, unsigned short int port); void outl(unsigned int value, unsigned short int port); void outl_p(unsigned int value, unsigned short int port); void insb(unsigned short int port, void *addr, unsigned long int count); void insw(unsigned short int port, void *addr, unsigned long int count); void insl(unsigned short int port, void *addr, unsigned long int count); void outsb(unsigned short int port, const void *addr, unsigned long int count); void outsw(unsigned short int port, const void *addr, unsigned long int count); void outsl(unsigned short int port, const void *addr, unsigned long int 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 optimiza- tion 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 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 2017-09-15 OUTB(2)

Featured Tech Videos