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Technical Reference: Communications, Volume 2

getnetbyaddr Subroutine

Purpose

Gets network entry by address.

Library

Standard C Library (libc.a)

Syntax

#include <netdb.h>


struct netent *getnetbyaddr (Network, Type)
long Network;
int Type;

Description

The getnetbyaddr subroutine is threadsafe in AIX 4.3 and later. However, the return value points to static data that is overwritten by subsequent calls. This data must be copied to be saved for use by subsequent calls.

The getnetbyaddr subroutine retrieves information from the /etc/networks file using the network address as a search key. The getnetbyaddr subroutine searches the file sequentially from the start of the file until it encounters a matching net number and type or until it reaches the end of the file.

The getnetbyaddr subroutine returns a pointer to a netent structure, which contains the equivalent fields for a network description line in the /etc/networks file. The netent structure is defined in the netdb.h file.

Use the endnetent subroutine to close the /etc/networks file.

All applications containing the getnetbyaddr subroutine must be compiled with _BSD set to a specific value. Acceptable values are 43 and 44. In addition, all socket applications must include the BSD libbsd.a library.

Parameters

Network Specifies the number of the network to be located.
Type Specifies the address family for the network. The only supported value is AF_INET.

Return Values

Upon successful completion, the getnetbyaddr subroutine returns a pointer to a netent structure.

If an error occurs or the end of the file is reached, the getnetbyaddr subroutine returns a null pointer.

Files

/etc/networks Contains official network names.

Related Information

The endnetent subroutine, getnetbyname subroutine, getnetent subroutine, setnetent subroutine.

Sockets Overview in AIX 5L Version 5.2 General Programming Concepts: Writing and Debugging Programs.

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