получить доступ к сети (get network entry)
Имя (Name)
getnetent, getnetbyname, getnetbyaddr, setnetent, endnetent - get
network entry
Синопсис (Synopsis)
#include <netdb.h>
struct netent *getnetent(void);
struct netent *getnetbyname(const char *name);
struct netent *getnetbyaddr(uint32_t net, int type);
void setnetent(int stayopen);
void endnetent(void);
Описание (Description)
The getnetent() function reads the next entry from the networks
database and returns a netent structure containing the broken-out
fields from the entry. A connection is opened to the database if
necessary.
The getnetbyname() function returns a netent structure for the
entry from the database that matches the network name.
The getnetbyaddr() function returns a netent structure for the
entry from the database that matches the network number net of
type type. The net argument must be in host byte order.
The setnetent() function opens a connection to the database, and
sets the next entry to the first entry. If stayopen is nonzero,
then the connection to the database will not be closed between
calls to one of the getnet*() functions.
The endnetent() function closes the connection to the database.
The netent structure is defined in <netdb.h> as follows:
struct netent {
char *n_name; /* official network name */
char **n_aliases; /* alias list */
int n_addrtype; /* net address type */
uint32_t n_net; /* network number */
}
The members of the netent structure are:
n_name The official name of the network.
n_aliases
A NULL-terminated list of alternative names for the
network.
n_addrtype
The type of the network number; always AF_INET.
n_net The network number in host byte order.
Возвращаемое значение (Return value)
The getnetent(), getnetbyname(), and getnetbyaddr() functions
return a pointer to a statically allocated netent structure, or a
null pointer if an error occurs or the end of the file is
reached.
Файлы (Files)
/etc/networks
networks database file
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌───────────────┬───────────────┬────────────────────────────────┐
│Interface │ Attribute │ Value │
├───────────────┼───────────────┼────────────────────────────────┤
│getnetent() │ Thread safety │ MT-Unsafe race:netent │
│ │ │ race:netentbuf env locale │
├───────────────┼───────────────┼────────────────────────────────┤
│getnetbyname() │ Thread safety │ MT-Unsafe race:netbyname env │
│ │ │ locale │
├───────────────┼───────────────┼────────────────────────────────┤
│getnetbyaddr() │ Thread safety │ MT-Unsafe race:netbyaddr │
│ │ │ locale │
├───────────────┼───────────────┼────────────────────────────────┤
│setnetent(), │ Thread safety │ MT-Unsafe race:netent env │
│endnetent() │ │ locale │
└───────────────┴───────────────┴────────────────────────────────┘
In the above table, netent in race:netent signifies that if any
of the functions setnetent(), getnetent(), or endnetent() are
used in parallel in different threads of a program, then data
races could occur.
Стандарты (Conforming to)
POSIX.1-2001, POSIX.1-2008, 4.3BSD.
Примечание (Note)
In glibc versions before 2.2, the net argument of getnetbyaddr()
was of type long.
Смотри также (See also)
getnetent_r(3), getprotoent(3), getservent(3)
RFC 1101
