The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.

#### NAME

> endnetent, getnetbyaddr, getnetbyname, getnetent, setnetent - network database functions

#### SYNOPSIS

> ``#include <netdb.h>
> void endnetent(void);
> struct netent *getnetbyaddr(uint32_t` net`, int` type`);
> struct netent *getnetbyname(const char *`name`);
> struct netent *getnetent(void);
> void setnetent(int` stayopen`);
> ``

#### DESCRIPTION

> These functions shall retrieve information about networks. This information is considered to be stored in a database that can be accessed sequentially or randomly. The implementation of this database is unspecified.

> The setnetent() function shall open and rewind the database. If the stayopen argument is non-zero, the connection to the net database shall not be closed after each call to getnetent() (either directly, or indirectly through one of the other getnet*() functions), and the implementation may maintain an open file descriptor to the database.

> The getnetent() function shall read the next entry of the database, opening and closing a connection to the database as necessary.

> The getnetbyaddr() function shall search the database from the beginning, and find the first entry for which the address family specified by type matches the n_addrtype member and the network number net matches the n_net member, opening and closing a connection to the database as necessary. The net argument shall be the network number in host byte order.

> The getnetbyname() function shall search the database from the beginning and find the first entry for which the network name specified by name matches the n_name member, opening and closing a connection to the database as necessary.

> The getnetbyaddr(), getnetbyname(), and getnetent() functions shall each return a pointer to a netent structure, the members of which shall contain the fields of an entry in the network database.

> The endnetent() function shall close the database, releasing any open file descriptor.

> These functions need not be reentrant. A function that is not required to be reentrant is not required to be thread-safe.

#### RETURN VALUE

> Upon successful completion, getnetbyaddr(), getnetbyname(), and getnetent() shall return a pointer to a netent structure if the requested entry was found, and a null pointer if the end of the database was reached or the requested entry was not found. Otherwise, a null pointer shall be returned.

#### ERRORS

> No errors are defined.

The following sections are informative.

#### EXAMPLES

> None.

#### APPLICATION USAGE

> The getnetbyaddr(), getnetbyname(), and getnetent() functions may return pointers to static data, which may be overwritten by subsequent calls to any of these functions.

#### RATIONALE

> None.

#### FUTURE DIRECTIONS

> None.

#### SEE ALSO

> The Base Definitions volume of IEEE Std 1003.1-2001, <netdb.h>

#### CHANGE HISTORY

> First released in Issue 6. Derived from the XNS, Issue 5.2 specification.

End of informative text.

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