This method of returning errors is used only in connection with obsolescent
The <netdb.h> header provides a declaration of h_errno
modifiable lvalue of type int.
It is unspecified whether h_errno is a macro or an identifier
declared with external linkage. If a macro definition is
suppressed in order to access an actual object, or a program defines
an identifier with the name h_errno, the behavior is
No errors are defined.
The following sections are informative.
Applications should obtain the definition of h_errno by the
inclusion of the <netdb.h> header.
h_errno may be withdrawn in a future version.
endhostent() , errno() , the Base Definitions volume of
IEEE Std 1003.1-2001, <netdb.h>
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at