NAME

getnetent, getnetbyaddr, getnetbyname, setnetent, endnetent − get network entry

USAGE

#include <netdb.h>
 
struct netent *getnetent()
 
struct netent *getnetbyname(name) char *name;
 
struct netent *getnetbyaddr(net, addrtype) long net; int addrtype;
 
setnetent(stayopen) int stayopen
 
endnetent()

DESCRIPTION

Getnetent, getnetbyname, and getnetbyaddr each return a pointer to an object with the following structure, which contains the various fields of a line in the network database, /etc/networks. 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; currently only AF_INET. 

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

Getnetent reads the next line of the file, opening the file if necessary. 

Setnetent opens and rewinds the file.  If the stayopen flag is non-zero, the net database will not be closed after each call to getnetent (either directly, or indirectly through one of the other “getnet” calls). 

Endnetent closes the file. 

Getnetbyname and getnetbyaddr search sequentially from the beginning of the file until a matching net name or net address is found or until EOF is encountered.  Network numbers are supplied in host order. 

NOTES

All information is kept in a static area, so it must be copied if you wish to save it.  These functions only understand the Internet address format.  If addrtype is supplied, it must be AF_INET. 

DIAGNOSTICS

Null pointer (zero) returned on EOF or error. 

FILES

/etc/networks database of reachable networks