getnetbyname() — Get a network entry by name
Standards
Standards / Extensions | C or C++ | Dependencies |
---|---|---|
XPG4.2 |
both |
Format
X/Open:
#define _XOPEN_SOURCE_EXTENDED 1
#include <netdb.h>
struct netent *getnetbyname(const char *name);
Berkeley
sockets:
#define _OE_SOCKETS
#include <netdb.h>
struct netent *getnetbyname(name);
General description
The getnetbyname()
call searches the tcpip.HOSTS.SITEINFO data
set for the specified network name.
- Parameter
- Description
- name
- The pointer to a network name.
You can use the X_SITE environment variable
to specify a data set other than tcpip.HOSTS.SITEINFO.
Note: For more information on these data sets and environment variables, tcpip.HOSTS.LOCAL, tcpip.HOSTS.SITEINFO,
and tcpip.HOSTS.SITEINFO, see z/OS Communications Server: IP Configuration Guide.
The getnetbyname() call returns a pointer to a netent structure for the network name specified on the call. getnetbyaddr(), getnetbyname(), and getnetent() all use the same static area to return the netent structure. This static area is only valid until the next one of these functions is called on the same thread.
The netent structure
is defined in the netdb.h include file and contains the following
elements:
- Element
- Description
- n_addrtype
- The type of network address returned. The call always sets this value to AF_INET.
- n_aliases
- An array, terminated with a NULL pointer, of alternative names for the network.
- n_name
- The official name of the network.
- n_net
- The network number, returned in host byte order.
Special behavior for C++: To use this function with C++, you must use the _XOPEN_SOURCE_EXTENDED 1 feature test macro.
Returned value
If successful, getnetbyname() returns a pointer to a netent structure. The return value points to static data that is overwritten by subsequent calls.
If unsuccessful, getnetbyname() returns a NULL pointer, indicating an error or End Of File (EOF).