getnetbyaddr()

Get a network entry, given an address (Unix)

Synopsis:

#include <netdb.h>

struct netent * getnetbyaddr( uint32_t net, 
                              int type );

Arguments:

net
The net address whose network entry you want to find.
type
The address type. This must currently be AF_INET.

Library:

libsocket

Use the -l socket option to qcc to link against this library.

Description:

The getnetbyaddr() function gets an entry for the given address, net, from the network database, /etc/networks.

This function returns a pointer to a structure of type netent , which contains the broken-out fields of a line in the network database.

The setnetent() function opens and rewinds the file. If you pass a nonzero stayopen argument to setnetent(), the network database isn't closed after each call to getnetbyname() , or getnetbyaddr().

The getnetbyname() and getnetbyaddr() functions sequentially search from the beginning of the file until a matching net name or net address and type is found, or until EOF is encountered. Network numbers are supplied in host order.

Returns:

A pointer to a valid netent structure, or NULL if an error occurs.

Files:

/etc/networks
Network name database file.

Classification:

POSIX 1003.1

Safety:  
Cancellation point Yes
Interrupt handler No
Signal handler No
Thread No

Caveats:

This function uses static data; if you need the data for future use, copy it before any subsequent calls overwrite it.

Only Internet network numbers are currently understood.

Last modified: 2013-12-23

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