man3/byteorder.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
   2 .\"
   3 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   4 .\"
   5 .\" References consulted:
   6 .\"     Linux libc source code
   7 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
   8 .\"     386BSD man pages
   9 .\" Modified Sat Jul 24 21:29:05 1993 by Rik Faith (faith@cs.unc.edu)
  10 .\" Modified Thu Jul 26 14:06:20 2001 by Andries Brouwer (aeb@cwi.nl)
  11 .\"
  12 .TH BYTEORDER 3  2021-03-22 "Linux man-pages (unreleased)" "Linux Programmer's Manual"
  13 .SH NAME
  14 htonl, htons, ntohl, ntohs \- convert values between host and network
  15 byte order
  16 .SH LIBRARY
  17 Standard C library
  18 .RI ( libc ", " \-lc )
  19 .SH SYNOPSIS
  20 .nf
  21 .B #include <arpa/inet.h>
  22 .PP
  23 .BI "uint32_t htonl(uint32_t " hostlong );
  24 .BI "uint16_t htons(uint16_t " hostshort );
  25 .PP
  26 .BI "uint32_t ntohl(uint32_t " netlong );
  27 .BI "uint16_t ntohs(uint16_t " netshort );
  28 .fi
  29 .SH DESCRIPTION
  30 The
  31 .BR htonl ()
  32 function converts the unsigned integer
  33 .I hostlong
  34 from host byte order to network byte order.
  35 .PP
  36 The
  37 .BR htons ()
  38 function converts the unsigned short integer
  39 .I hostshort
  40 from host byte order to network byte order.
  41 .PP
  42 The
  43 .BR ntohl ()
  44 function converts the unsigned integer
  45 .I netlong
  46 from network byte order to host byte order.
  47 .PP
  48 The
  49 .BR ntohs ()
  50 function converts the unsigned short integer
  51 .I netshort
  52 from network byte order to host byte order.
  53 .PP
  54 On the i386 the host byte order is Least Significant Byte first,
  55 whereas the network byte order, as used on the Internet, is Most
  56 Significant Byte first.
  57 .SH ATTRIBUTES
  58 For an explanation of the terms used in this section, see
  59 .BR attributes (7).
  60 .ad l
  61 .nh
  62 .TS
  63 allbox;
  64 lbx lb lb
  65 l l l.
  66 Interface       Attribute       Value
  67 T{
  68 .BR htonl (),
  69 .BR htons (),
  70 .BR ntohl (),
  71 .BR ntohs ()
  72 T}      Thread safety   MT-Safe
  73 .TE
  74 .hy
  75 .ad
  76 .sp 1
  77 .SH STANDARDS
  78 POSIX.1-2001, POSIX.1-2008.
  79 .SH SEE ALSO
  80 .BR bswap (3),
  81 .BR endian (3),
  82 .BR gethostbyname (3),
  83 .BR getservent (3)