freebsd-nq/share/man/man9/byteorder.9

.\" Copyright (c) 2002 Mike Barcroft <mike@FreeBSD.org>
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.Dd April 29, 2002
.Dt BYTEORDER 9
.Os
.Sh NAME
.Nm be16toh , be32toh , be64toh , htobe16 , htobe32 , htobe64 ,
.Nm htole16 , htole32 , htole64 , le16toh , le32toh , le64toh
.Nd convert values between big endian, little endian, and host byte order
.\" XXX the following breaks whatis(1)
.Pp
.Nm be16enc , be16dec , be32enc , be32dec , be64enc , be64dec ,
.Nm le16enc , le16dec , le32enc , le32dec , le64enc , le64dec
.Nd encode and decode big or little endian values to and from byte strings
.Sh SYNOPSIS
.In sys/endian.h
.Ft uint16_t
.Fn bswap16 "uint16_t int16"
.Ft uint32_t
.Fn bswap32 "uint32_t int32"
.Ft uint64_t
.Fn bswap64 "uint64_t int64"
.Ft uint16_t
.Fn be16toh "uint16_t big16"
.Ft uint32_t
.Fn be32toh "uint32_t big32"
.Ft uint64_t
.Fn be64toh "uint64_t big64"
.Ft uint16_t
.Fn htobe16 "uint16_t host16"
.Ft uint32_t
.Fn htobe32 "uint32_t host32"
.Ft uint64_t
.Fn htobe64 "uint64_t host64"
.Ft uint16_t
.Fn htole16 "uint16_t host16"
.Ft uint32_t
.Fn htole32 "uint32_t host32"
.Ft uint64_t
.Fn htole64 "uint64_t host64"
.Ft uint16_t
.Fn le16toh "uint16_t little16"
.Ft uint32_t
.Fn le32toh "uint32_t little32"
.Ft uint64_t
.Fn le64toh "uint64_t little64"
.Ft uint16_t
.Fn be16dec "const void *"
.Ft uint32_t
.Fn be32dec "const void *"
.Ft uint64_t
.Fn be64dec "const void *"
.Ft uint16_t
.Fn le16dec "const void *"
.Ft uint32_t
.Fn le32dec "const void *"
.Ft uint64_t
.Fn le64dec "const void *"
.Ft void
.Fn be16enc "void *" uint16_t
.Ft void
.Fn be32enc "void *" uint32_t
.Ft void
.Fn be64enc "void *" uint64_t
.Ft void
.Fn le16enc "void *" uint16_t
.Ft void
.Fn le32enc "void *" uint32_t
.Ft void
.Fn le64enc "void *" uint64_t
.Sh DESCRIPTION
The
.Fn bswap16 ,
.Fn bswap32 ,
and
.Fn bswap64
functions return a byte order swapped integer.
On big endian systems, the number is converted to little endian byte order.
On little endian systems, the number is converted to big endian byte order.
.Pp
The
.Fn be16toh ,
.Fn be32toh ,
and
.Fn be64toh
functions return a big endian byte ordered integer
converted to the system's native byte order.
The return value will be the same as the argument on big endian systems.
.Pp
The
.Fn le16toh ,
.Fn le32toh ,
and
.Fn le64toh
functions return a little endian byte ordered integer
converted to the system's native byte order.
The return value will be the same as the argument on little endian systems.
.Pp
The
.Fn htobe16 ,
.Fn htobe32 ,
and
.Fn htobe64
functions return a integer in the system's native
byte order converted to big endian byte order.
The return value will be the same as the argument on big endian systems.
.Pp
The
.Fn htole16 ,
.Fn htole32 ,
and
.Fn htole64
functions return a integer in the system's native
byte order converted to little endian byte order.
The return value will be the same as the argument on little endian systems.
.Pp
The
.Fn be16enc ,
.Fn be16dec ,
.Fn be32enc ,
.Fn be32dec ,
.Fn be64enc ,
.Fn be64dec ,
.Fn le16enc ,
.Fn le16dec ,
.Fn le32enc ,
.Fn le32dec ,
.Fn le64enc ,
and
.Fn le64dec
functions encode and decode integers to/from byte strings on any alignment
in big/little endian format.
.Sh SEE ALSO
.Xr byteorder 3
.Sh HISTORY
The
.Fn hto*
and
.Fn toh*
functions first appeared in
.Fx 5.0 ,
and were originally developed by the
.Nx
project.
.Pp
The encode/decode functions first appeared in
.Fx 5.1 .