h_errno

Host error variable

Synopsis:

#include <netdb.h>

extern int h_errno;

Library:

libsocket

Use the -l socket option to qcc to link against this library.

Description:

The h_errno variable can be set by any one of the following functions:

It can be set to any one of the following:

HOST_NOT_FOUND
Authoritative answer: Unknown host.
NETDB_INTERNAL
You specified an invalid address family when calling gethostbyname2().
NO_DATA
Valid name, no data record of the requested type. The name is known to the name server, but has no IP address associated with it—this isn't a temporary error. Another type of request to the name server using this domain name will result in an answer (e.g. a mail-forwarder may be registered for this domain).
NO_RECOVERY
Unknown server error. An unexpected server failure was encountered. This is a nonrecoverable network error.
TRY_AGAIN
Nonauthoritative answer: Host name lookup failure. This is usually a temporary error and means that the local server didn't receive a response from an authoritative server. A retry at some later time may succeed.

Classification:

POSIX 1003.1 OBS

Caveats:

Unlike errno, h_errno isn't thread-safe.

See also:

errno, gethostbyaddr(), gethostbyaddr_r(), gethostbyname(), gethostbyname2(), gethostbyname_r(), res_query(), res_search()