---
name: "getnetent"
section: "3bind"
platform: "linux"
package: "bind-dev"
version: "1:8.4.7-1"
release: "Debian 4.0 (Etch)"
platforms: ["linux"]
url: "https://new.carta.tech/getnetent/3bind"
---

# getnetent(3bind)

get networks entry

## NAME

**getnetent**, **getnetbyaddr**, **getnetbyname**, **setnetent**, **endnetent** – get networks entry

## SYNOPSIS

**#include \<netdb.h\>**

*struct* *netent* *\**\

**getnetent**();

*struct* *netent* *\**\

**getnetbyname**(*char name*);

*struct* *netent* *\**\

**getnetbyaddr**(*unsigned long net*, *int type*);

*void*\

**setnetent**(*int stayopen*);

*void*\

**endnetent**();

## DESCRIPTION

The **getnetent**(), **getnetbyname**(), and **getnetbyaddr**() subroutines each return a pointer to an object with the following structure containing the broken-out fields of a line in the  *networks* database.

```
struct	netent {
	char	*n_name;	/* official name of net */
	char	**n_aliases;	/* alias list */
	int	n_addrtype;	/* net number type */
	long	n_net;		/* net number */
};
```

The members of this structure are:

- n\_name

  The official name of the network.

- n\_aliases

  A zero-terminated list of alternate names for the network.

- n\_addrtype

  The type of the network number returned:  AF\_INET.

- n\_net

  The network number.  Network numbers are returned in machine byte order.

If the *stayopen* flag on a  **setnetent**() subroutine is NULL, the *networks* database is opened.  Otherwise, the **setnetent**() has the effect of rewinding the  *networks* database. The **endnetent**() subroutine may be called to close the  *networks* database when processing is complete.

The **getnetent**() subroutine simply reads the next line while **getnetbyname**() and **getnetbyaddr**() search until a matching *name* or *net* number is found (or until  EOF is encountered).  The  *type*, *must*, *be* AF\_INET. The **getnetent**() subroutine keeps a pointer in the database, allowing successive calls to be used to search the entire file.

Before a **while** loop using **getnetent**(), a call to **setnetent**() must be made  in order to perform initialization; a call to  **endnetent**() must be used after the loop.  Both **getnetbyname**() and **getnetbyaddr**() make calls to **setnetent**() and **endnetent**().

## FILES

*/etc/networks*

## DIAGNOSTICS

Null pointer (0) returned on  EOF or error.

## SEE ALSO

[networks(5)](/networks/5.md), RFC 1101.

## HISTORY

The  **getnetent**(), **getnetbyaddr**(), **getnetbyname**(), **setnetent**(), and **endnetent**() functions appeared in 4.2BSD.

## BUGS

The data space used by these functions is static; if future use requires the data, it should be copied before any subsequent calls to these functions overwrite it.  Only Internet network numbers are currently understood. Expecting network numbers to fit in no more than 32 bits is probably naive.