Comtrol eCos - Manual (Page 520)

Chapter 38. TCP/IP Library Reference
the same as that returned by hstrerror() with argument h_errno.
FILES
/etc/hosts
/etc/resolv.conf
DIAGNOSTICS
Error return status from gethostbyname(), gethostbyname2(), and
gethostbyaddr() is indicated by return of a null pointer. The external
integer h_errno may then be checked to see whether this is a temporary
failure or an invalid or unknown host.
The variable h_errno can have the following values:
HOST_NOT_FOUND No such host is known.
TRY_AGAIN This is usually a temporary error and means that the
local server did not receive a response from an authori-
tative server. A retry at some later time may succeed.
NO_RECOVERY Some unexpected server failure was encountered. This is
a non-recoverable error.
NO_DATA The requested name is valid but does not have an IP
address; this is not a temporary error. This means that
the name is known to the name server but there is no
address associated with this name. Another type of
request to the name server using this domain name will
result in an answer; for example, a mail-forwarder may be
registered for this domain.
SEE ALSO
resolver(3), getaddrinfo(3), getnameinfo(3), hosts(5), resolv.conf(5),
hostname(7), named(8)
CAVEAT
If the search routines in resolv.conf(5) decide to read the /etc/hosts
file, gethostent() and other functions will read the next line of the
file, re-opening the file if necessary.
The sethostent() function opens and/or rewinds the file /etc/hosts. If
the stayopen argument is non-zero, the file will not be closed after each
call to gethostbyname(), gethostbyname2(), or gethostbyaddr().
The endhostent() function closes the file.
HISTORY
The herror() function appeared in 4.3BSD. The endhostent(),
gethostbyaddr(), gethostbyname(), gethostent(), and sethostent() func-
tions appeared in 4.2BSD.
BUGS
These functions use static data storage; if the data is needed for future
use, it should be copied before any subsequent calls overwrite it. Only
the Internet address formats are currently understood.
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