mirror of https://github.com/mkerrisk/man-pages
106 lines
3.5 KiB
Plaintext
106 lines
3.5 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "INET_ADDR" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" inet_addr
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.SH NAME
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inet_addr, inet_ntoa \- IPv4 address manipulation
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.SH SYNOPSIS
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.LP
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\fB#include <arpa/inet.h>
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.br
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.sp
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in_addr_t inet_addr(const char *\fP\fIcp\fP\fB);
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.br
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char *inet_ntoa(struct in_addr\fP \fIin\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The \fIinet_addr\fP() function shall convert the string pointed to
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by \fIcp\fP, in the standard IPv4 dotted decimal notation,
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to an integer value suitable for use as an Internet address.
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.LP
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The \fIinet_ntoa\fP() function shall convert the Internet host address
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specified by \fIin\fP to a string in the Internet
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standard dot notation.
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.LP
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The \fIinet_ntoa\fP() function need not be reentrant. A function that
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is not required to be reentrant is not required to be
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thread-safe.
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.LP
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All Internet addresses shall be returned in network order (bytes ordered
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from left to right).
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.LP
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Values specified using IPv4 dotted decimal notation take one of the
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following forms:
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.TP 7
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\fBa.b.c.d\fP
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When four parts are specified, each shall be interpreted as a byte
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of data and assigned, from left to right, to the four bytes
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of an Internet address.
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.TP 7
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\fBa.b.c\fP
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When a three-part address is specified, the last part shall be interpreted
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as a 16-bit quantity and placed in the rightmost two
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bytes of the network address. This makes the three-part address format
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convenient for specifying Class B network addresses as
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\fB"128.net.host"\fP .
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.TP 7
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\fBa.b\fP
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When a two-part address is supplied, the last part shall be interpreted
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as a 24-bit quantity and placed in the rightmost three
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bytes of the network address. This makes the two-part address format
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convenient for specifying Class A network addresses as
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\fB"net.host"\fP .
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.TP 7
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\fBa\fP
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When only one part is given, the value shall be stored directly in
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the network address without any byte rearrangement.
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.sp
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.LP
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All numbers supplied as parts in IPv4 dotted decimal notation may
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be decimal, octal, or hexadecimal, as specified in the
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ISO\ C standard (that is, a leading 0x or 0X implies hexadecimal;
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otherwise, a leading \fB'0'\fP implies octal; otherwise,
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the number is interpreted as decimal).
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.SH RETURN VALUE
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.LP
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Upon successful completion, \fIinet_addr\fP() shall return the Internet
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address. Otherwise, it shall return (
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\fBin_addr_t\fP)(-1).
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.LP
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The \fIinet_ntoa\fP() function shall return a pointer to the network
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address in Internet standard dot notation.
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.SH ERRORS
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.LP
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No errors are defined.
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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The return value of \fIinet_ntoa\fP() may point to static data that
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may be overwritten by subsequent calls to
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\fIinet_ntoa\fP().
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIendhostent\fP() , \fIendnetent\fP() , the Base Definitions
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volume of IEEE\ Std\ 1003.1-2001, \fI<arpa/inet.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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