61 lines
1.4 KiB
Groff
61 lines
1.4 KiB
Groff
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.TH HTON 3
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.SH NAME
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hton, htons, htonl, ntohs, ntohl \- host to network byte order conversion
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.SH SYNOPSIS
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.ft B
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.nf
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#define _MINIX_SOURCE 1
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#include <stddef.h>
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#include <sys/types.h>
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#include <net/hton.h>
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u16_t htons(u16_t \fIhost_word\fP)
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u32_t htonl(u32_t \fIhost_dword\fP)
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u16_t ntohs(u16_t \fInetwork_word\fP)
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u32_t ntohl(u32_t \fInetwork_dword\fP)
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u16_t HTONS(u16_t \fIhost_word\fP)
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u32_t HTONL(u32_t \fIhost_dword\fP)
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u16_t NTOHS(u16_t \fInetwork_word\fP)
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u32_t NTOHL(u32_t \fInetwork_dword\fP)
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.fi
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.ft R
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.SH DESCRIPTION
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These macros convert 16-bit and 32-bit quantities to and from the network
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byte order used by the TCP/IP protocols.
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The function of the macros is encoded in their name.
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.B H
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means host byte order,
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.B n
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means network byte order,
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.B s
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means a 16-bit quantity and
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.B l
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means a 32-bit quantity.
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Thus
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.B htons
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converts a 16-bit quantity from host byte order to network byte order.
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The difference between the lower case and upper case variants is that
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the lower case variants evaluate the argument at most once and the
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upper case variants can be used for constant folding.
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That is,
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.PP
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.RS
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htonl(f(x))
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.RE
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.PP
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will call f(x) at most once and
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.PP
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.RS
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HTONS(0x10)
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.RE
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.PP
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will be equivalent to 0x10 on a big-endian machine and 0x1000 on a
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little-endian machine.
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.SH "SEE ALSO"
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.BR ip (4).
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.SH AUTHOR
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Philip Homburg (philip@cs.vu.nl)
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.\"
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.\" $PchId: hton.3,v 1.3 1996/02/22 21:10:01 philip Exp $
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