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getnetbyaddr(3)
NAME
  getnetbyaddr, getnetbyaddr_r - Get a network entry by address

SYNOPSIS
  #include <netdb.h>

  struct netent *getnetbyaddr(
	  in_addr_t num,
	  int type );

  [Tru64 UNIX]	The following obsolete function is supported in order to
  maintain backward compatibility with previous versions of the operating
  system.  You should not use it in new designs.

  int getnetbyaddr_r(
	  int num,
	  int type,
	  struct netent *net,
	  struct netent_data *net_data );

  [Tru64 UNIX]	The following definition of the getnetbyaddr() function does
  not conform to current standards and is supported only for backward
  compatibility:

  struct netent *getnetbyaddr(
	  int num,
	  int type );

LIBRARY
  Standard C Library (libc)

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  getnetbyaddr():  XNS4.0, XNS5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  num Specifies the number of the network in host-byte order.

  net [Tru64 UNIX]  For getnetbyaddr_r(), this points to the netent
      structure.  The netdb.h header file defines the netent structure.

  type
      Specifies the Internet domain address format. The value AF_INET must be
      used.

  num [Tru64 UNIX]  Specifies the number of the network in host-byte order.

  net_data
      [Tru64 UNIX]  Is data for the networks database.	The netdb.h header
      file defines the netent_data structure.

DESCRIPTION
  The getnetbyaddr() function returns a pointer to a structure of type
  netent.  Its members specify data obtained from either the local
  /etc/networks file or the NIS distributed networks file. To determine which
  file or files to search, and in which order, the system uses the switches
  in the /etc/svc.conf file.  The netdb.h header file defines the netent
  structure.

  The getnetbyaddr() function searches the network database file sequentially
  until a match with the num and type parameters occurs. The num parameter
  must specify the network number in host-byte order. The type parameter must
  be the constant AF_INET.  When EOF (End-of-File) is reached without a
  match, an error value is returned by this parameter.

  Use the endnetent() function to close the networks file.

NOTES
  The getnetbyaddr() function and its backward compatible version return a
  pointer to thread-specific data.  Subsequent calls to these or related
  functions from the same thread overwrite this data.

  [Tru64 UNIX]	The getnetbyaddr_r() function is an obsolete reentrant
  version of the getnetbyaddr() function.    It is supported in order to
  maintain backward compatibility with previous versions of the operating
  system and should not be used in new designs.	 Note that you must set the
  net_fp field of the netent_data structure to NULL before its first access
  by either the setnetent_r() or getnetbyaddr_r() function.

  You must initialize the _net_stayopen option of the netent_data structure
  if you are not using the setnetent() function.

RETURN VALUES
  Upon successful completion, the getnetbyaddr() function and its backward
  compatible version return a pointer to a netent structure.   If it fails or
  reaches the end of the /etc/networks name file, it returns a null pointer.

  [Tru64 UNIX]	Upon successful completion, the getnetbyaddr_r() function
  stores the netent structure in the location pointed to by net, and returns
  a value of 0 (zero).	Upon failure, it returns a value of -1.

ERRORS
  Current industry standards do not define error values for the
  getnetbyaddr() function.

  [Tru64 UNIX]	If any of the following conditions occurs, the
  getnetbyaddr_r() function sets errno to the corresponding value:

  [EINVAL]
      The net or net_data parameter is invalid.

  [ESRCH]
      The search failed.

FILES
  /etc/networks
      The Internet network name database file. Each record in the file
      occupies a single line and has three fields: the official network name,
      the network number, and alias.

SEE ALSO
  Functions: endnetent(3), getnetent(3), getnetbyname(3), setnetent(3).

  Files: networks(4), svc.conf(4).

  Networks: nis_intro(7).

  Standards: standards(5).

  Network Programmer's Guide

Index for Section 3

Alphabetical listing for G

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