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| 1 | .TH HTON 3
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| 2 | .SH NAME
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| 3 | hton, htons, htonl, ntohs, ntohl \- host to network byte order conversion
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| 4 | .SH SYNOPSIS
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| 5 | .ft B
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| 6 | .nf
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| 7 | #define _MINIX_SOURCE 1
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| 8 | #include <stddef.h>
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| 9 | #include <sys/types.h>
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| 10 |
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| 11 | #include <net/hton.h>
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| 12 |
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| 13 | u16_t htons(u16_t \fIhost_word\fP)
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| 14 | u32_t htonl(u32_t \fIhost_dword\fP)
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| 15 | u16_t ntohs(u16_t \fInetwork_word\fP)
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| 16 | u32_t ntohl(u32_t \fInetwork_dword\fP)
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| 17 | u16_t HTONS(u16_t \fIhost_word\fP)
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| 18 | u32_t HTONL(u32_t \fIhost_dword\fP)
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| 19 | u16_t NTOHS(u16_t \fInetwork_word\fP)
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| 20 | u32_t NTOHL(u32_t \fInetwork_dword\fP)
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| 21 | .fi
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| 22 | .ft R
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| 23 | .SH DESCRIPTION
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| 24 | These macros convert 16-bit and 32-bit quantities to and from the network
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| 25 | byte order used by the TCP/IP protocols.
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| 26 | The function of the macros is encoded in their name.
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| 27 | .B H
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| 28 | means host byte order,
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| 29 | .B n
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| 30 | means network byte order,
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| 31 | .B s
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| 32 | means a 16-bit quantity and
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| 33 | .B l
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| 34 | means a 32-bit quantity.
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| 35 | Thus
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| 36 | .B htons
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| 37 | converts a 16-bit quantity from host byte order to network byte order.
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| 38 | The difference between the lower case and upper case variants is that
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| 39 | the lower case variants evaluate the argument at most once and the
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| 40 | upper case variants can be used for constant folding.
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| 41 | That is,
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| 42 | .PP
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| 43 | .RS
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| 44 | htonl(f(x))
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| 45 | .RE
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| 46 | .PP
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| 47 | will call f(x) at most once and
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| 48 | .PP
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| 49 | .RS
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| 50 | HTONS(0x10)
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| 51 | .RE
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| 52 | .PP
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| 53 | will be equivalent to 0x10 on a big-endian machine and 0x1000 on a
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| 54 | little-endian machine.
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| 55 | .SH "SEE ALSO"
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| 56 | .BR ip (4).
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| 57 | .SH AUTHOR
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| 58 | Philip Homburg (philip@cs.vu.nl)
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| 59 | .\"
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| 60 | .\" $PchId: hton.3,v 1.3 1996/02/22 21:10:01 philip Exp $
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