GETNETENT

Section: C Library Functions (3)
Index Return to Main Contents

BSD mandoc
BSD 4.2

NAME

getnetent getnetbyaddr getnetbyname setnetent endnetent - get network entry

SYNOPSIS

Fd #include <netdb.h> Ft struct netent * Fn getnetent Ft struct netent * Fn getnetbyname char *name Ft struct netent * Fn getnetbyaddr long net int type Fn setnetent int stayopen Fn endnetent

DESCRIPTION

The Fn getnetent , Fn getnetbyname , and Fn getnetbyaddr functions each return a pointer to an object with the following structure containing the broken-out fields of a line in the network data base, /etc/networks

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

The members of this structure are:

Fa n_name: The official name of the network.
Fa n_aliases: A zero terminated list of alternate names for the network.
Fa n_addrtype: The type of the network number returned; currently only AF_INET.
Fa n_net: The network number. Network numbers are returned in machine byte order.

The Fn getnetent function reads the next line of the file, opening the file if necessary.

The Fn setnetent function opens and rewinds the file. If the Fa stayopen flag is non-zero, the net data base will not be closed after each call to Fn getnetbyname or Fn getnetbyaddr .

The Fn endnetent function closes the file.

The Fn getnetbyname function and Fn getnetbyaddr 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.

FILES

/etc/networks

DIAGNOSTICS

Null pointer (0) returned on EOF or error.

HISTORY

The Fn getnetent , Fn getnetbyaddr , Fn getnetbyname , Fn setnetent , and Fn endnetent functions appeared in BSD 4.2

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.

This document was created by man2html, using the manual pages.
Time: 15:52:53 GMT, January 15, 2023