# fn:unparsed-text-available - XPath XQuery Reference

Because errors in evaluating the fn:unparsed-text function are
            non-recoverable, these two functions are provided to allow an application to determine
            whether a call with particular arguments would succeed.deterministiccontext-dependentfocus-independentThe fn:unparsed-text-available function determines whether a call
            on the fn:unparsed-text function with identical arguments would
            return a string.If the first argument is an empty sequence, the function returns false. In other cases, the function returns true if a call on
               fn:unparsed-text with the same arguments would succeed, and
            false if a call on fn:unparsed-text with the same arguments would
            fail with a non-recoverable dynamic error.The functions fn:unparsed-text and
               fn:unparsed-text-available have the same requirement for
               determinism as the functions
               fn:doc and fn:doc-available. This means that unless the
            user has explicitly stated a requirement for a reduced level of determinism, either of
            these functions if called twice with the same arguments during the course of a
            transformation must return the same results each time; moreover, the
            results of a call on fn:unparsed-text-availablemust be consistent with the results of a subsequent call on
               unparsed-text with the same arguments.This requires that the fn:unparsed-text-available function should
            actually attempt to read the resource identified by the URI, and check that it is
            correctly encoded and contains no characters that are invalid in XML. Implementations
            may avoid the cost of repeating these checks for example by caching the validated
            contents of the resource, to anticipate a subsequent call on the
               fn:unparsed-text or fn:unparsed-text-lines
            function. Alternatively, implementations may be able to rewrite an expression such as
               if (unparsed-text-available(A)) then unparsed-text(A) else ... to
            generate a single call internally.Since the function fn:unparsed-text-lines succeeds or fails under
            exactly the same circumstances as fn:unparsed-text, the
               fn:unparsed-text-available function may equally be used to test
            whether a call on fn:unparsed-text-lines would succeed.