This error return value is part of the XTI interfaces that evolved from the TLI interfaces. XTI represents the future evolution of these interfaces. However, TLI interfaces are supported for compatibility. When using a TLI interface that has the same name as an XTI interfaces, a different headerfile, <tiuser.h>, must be used. Refer the the TLI COMPATIBILITY section for a description of differences between the two interfaces.
t_errno is used by XTI functions to return error values.
XTI functions provide an error number in t_errno which has type int and is defined in <xti.h>. The value of t_errno will be defined only after a call to a XTI function for which it is explicitly stated to be set and until it is changed by the next XTI function call. The value of t_errno should only be examined when it is indicated to be valid by a function's return value. Programs should obtain the definition of t_errno by the inclusion of <xti.h>. The practice of defining t_errno in program as extern int t_errno is obsolescent. No XTI function sets t_errno to 0 to indicate an error.
It is unspecified whether t_errno is a macro or an identifier with external linkage. It represents a modifiable lvalue of type int. If a macro definition is suppressed in order to access an actual object or a program defines an identifier with name t_errno, the behavior is undefined.
The symbolic values stored in t_errno by an XTI function are defined in the ERRORS sections in all relevant XTI function definition pages.
t_errno is also used by TLI functions to return error values.
The XTI and TLI interface definitions have common names but use different header files. This, and other semantic differences between the two interfaces are described in the subsections below.
The XTI interfaces use the header file, <xti.h>. TLI interfaces should not use this header. They should use the header:
The t_errno values that can be set by the XTI interface but cannot be set by the TLI interface are:
See attributes(5) for descriptions of the following attributes: