NAME

om_instance - Determines whether an object is an instance of a particular class or any of its subclasses

SYNOPSIS

#include <xom.h>

OM_return_code om_instance(
        OM_object subject,
        OM_object_identifier class,
        OM_boolean *instance);

PARAMETERS

Input

subject: The subject that remains accessible.
class: Identifies the class in question.

Output

instance: Indicates whether the subject is an instance of the specified class or any of its subclasses. This result is present if and only if the value of the OM_return_code is set to OM_SUCCESS.

DESCRIPTION

The om_instance() function determines whether a service-generated public or private object (the subject) is an instance of a particular class or any of its subclasses.

NOTES

The client can determine an object's class (C) by simply inspecting the object, using programming language constructs if the object is public or om_get() if it is private. This function is useful in that it reveals that an object is an instance of the specified class, even if C is a subclass of that class.

RETURN VALUES

OM_return_code: Indicates whether the function succeeded and, if not, why not. If the function is successful, the value of OM_return_code is set to OM_SUCCESS; if the function fails, it has one of the error values listed in this reference page.
The exact constants for OM_return_code are defined in the xom.h header file (see the xom.h(4xom) reference page).

ERRORS

OM_FUNCTION_INTERRUPTED
OM_MEMORY_INSUFFICIENT
OM_NETWORK_ERROR
OM_NO_SUCH_CLASS
OM_NO_SUCH_OBJECT
OM_NO_SUCH_SYNTAX
OM_NOT_THE_SERVICES
OM_PERMANENT_ERROR
OM_POINTER_INVALID
OM_SYSTEM_ERROR
OM_TEMPORARY_ERROR