Hello,
A few months ago Ulrich Drepper added a family of byteorder conversion
macros to glibc.
I've written a rough manpage for them; attached.
The colophon may have the wrong version, I just guessed it.
The endian.3 file needs an big bundle of links to it, listed below:
betoh64
betoh32
betoh16
htobe64
htobe32
htobe16
letoh64
letoh32
letoh16
htole64
htole32
htole16
Also, the existing byteorder.3 manpage should get a "SEE ALSO" reference
to the new family:
.BR endian (3)
Regards,
Nanno
PS. Please CC me explicitly on any email, I'm not on the 'vger' list.
.\" Written by Nanno Langstraat, released into the Public Domain
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date. The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein. The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.TH ENDIAN 3 2008-07-08 "GNU" "Linux Programmer's Manual"
.SH NAME
htobeNN, htoleNN, betohNN, letohNN \- convert values between host and
big/little-endian byte order
.SH SYNOPSIS
.nf
.B #define __USE_BSD
.B #include <endian.h>
.sp
.BI "uint64_t htobe64(uint64_t " host_64bits );
.sp
.BI "uint16_t letoh16(uint16_t " little_endian_16bits );
.sp
.BI "uint32_t betoh32(uint32_t " big_endian_32bits );
.sp
...
etc.
.fi
.SH DESCRIPTION
These functions convert the byte encoding of integer values from
the byte order that the current CPU (the "host") happens to use,
to the standard little-endian / big-endian byte orders, and back
again.
The functions all follow the following naming pattern:
.BR {SRC} to {DST}{BITS} ().
.BI {SRC}
is the byte order of the input parameter,
.BI {DST}
is the byte order of the desired return value.
These can be
.BI be
for "big endian",
.BI le
for "little endian", or
.BI h
for "host".
.BI {BITS}
is the number of bits of the value. It can currently be
.BI 16
,
.BI 32
or
.BI 64 .
.SH VERSIONS
These function were added to GNU glibc version 2.8.90.
.SH "CONFORMING TO"
OpenBSD contains these functions, but requires <sys/endian.h> instead of
<endian.h>.
FreeBSD has not (as of 2008) adopted these functions.
.SH NOTES
These
.BR endian (3)
functions are similar to the older
.BR byteorder (3)
family of functions.
For example,
.BR betoh32 ()
is identical to
.BR ntohl () .
The advantage of the
.BR byteorder (3)
functions is that they are available on most operating systems. Their drawback
is that they were designed only for use in the context of TCP/IP. They
therefore lack 64-bit variants and little-endian variants.
.SH EXAMPLE
Given the following code:
uint8_t file_input[4] = { 0x12, 0x34, 0x56, 0x78 };
uint32_t out = betoh32( (uint32_t*)file_input );
Variable "out" will equal 0x12345678.
(Unrelated side note: this short code example is not alignment-safe in
the (uint32_t*) pointer cast)
.SH "SEE ALSO"
.BR byteorder (3)
.SH COLOPHON
This page is part of release 3.04 of the Linux
.I man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
