huschi.net

INET_ADDR(3P)              POSIX Programmer's Manual             INET_ADDR(3P)
PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       inet_addr, inet_ntoa -- IPv4 address manipulation
SYNOPSIS
       #include <arpa/inet.h>
       in_addr_t inet_addr(const char *cp);
       char *inet_ntoa(struct in_addr in);
DESCRIPTION
       The inet_addr() function shall convert the string pointed to by cp,  in
       the standard IPv4 dotted decimal notation, to an integer value suitable
       for use as an Internet address.
       The inet_ntoa() function shall convert the Internet host address speci-
       fied by in to a string in the Internet standard dot notation.
       The inet_ntoa() function need not be thread-safe.
       All  Internet  addresses  shall  be  returned  in  network order (bytes
       ordered from left to right).
       Values specified using IPv4 dotted decimal notation  take  one  of  the
       following forms:
       a.b.c.d   When four parts are specified, each shall be interpreted as a
                 byte of data and assigned, from left to right,  to  the  four
                 bytes of an Internet address.
       a.b.c     When  a  three-part address is specified, the last part shall
                 be interpreted as a 16-bit quantity and placed in the  right-
                 most  two bytes of the network address. This makes the three-
                 part address format convenient for specifying Class B network
                 addresses as "128.net.host".
       a.b       When  a  two-part address is supplied, the last part shall be
                 interpreted as a 24-bit quantity and placed in the  rightmost
                 three  bytes  of the network address. This makes the two-part
                 address format convenient  for  specifying  Class  A  network
                 addresses as "net.host".
       a         When  only  one  part  is  given,  the  value shall be stored
                 directly in the network address without any  byte  rearrange-
                 ment.
       All  numbers  supplied  as parts in IPv4 dotted decimal notation may be
       decimal, octal, or hexadecimal, as  specified  in  the  ISO C  standard
       (that  is, a leading 0x or 0X implies hexadecimal; otherwise, a leading
       '0' implies octal; otherwise, the number is interpreted as decimal).
RETURN VALUE
       Upon successful  completion,  inet_addr()  shall  return  the  Internet
       address. Otherwise, it shall return (in_addr_t)(-1).
       The  inet_ntoa() function shall return a pointer to the network address
       in Internet standard dot notation.
ERRORS
       No errors are defined.
       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       The return value of inet_ntoa() may point to static data  that  may  be
       overwritten by subsequent calls to inet_ntoa().
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       endhostent(), endnetent()
       The Base Definitions volume of POSIX.1-2008, <arpa_inet.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.unix.org/online.html .
       Any typographical or formatting errors that appear  in  this  page  are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors,  see  https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                        INET_ADDR(3P)