h_errno

global variable used by name resolution functions to return error values 

Global Variable


SYNOPSIS

#include <netdb.h>

extern int h_errno;


DESCRIPTION

The h_errno variable is used by the name resolution functions to return error values. The value of h_errno is defined only after a call to a function for which it is explicitly stated to be set and until it is changed by the next function call. The value of h_errno should only be examined when it is indicated to be valid by a function's return value. Programs should obtain the definition of h_errno by the inclusion of <netdb.h>. The practice of defining h_errno in a program as

extern int h_errno;

(without including <netdb.h>) is unsupported.

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 the actual object, or a program defines an identifier with the name h_errno, the behavior is undefined.

The symbolic values stored in h_errno are documented in the RETURN VALUES section on all relevant pages.


CONFORMANCE

UNIX 98, with exceptions.


PORTING ISSUES

UNIX 98 allows h_errno to be declared without including <netdb.h>. This is not supported by the NuTCRACKER Platform.


AVAILABILITY

PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Professional Developers 64-Bit Edition
PTC MKS Toolkit for Enterprise Developers
PTC MKS Toolkit for Enterprise Developers 64-Bit Edition


SEE ALSO

Functions:
herror(), hstrerror(), perror(), strerror()

Miscellaneous:
errno, sys_errlist, sys_nerr


PTC MKS Toolkit 10.3 Documentation Build 39.