(no version information, might be only in CVS)
This function is equivalent to calling php_stream_cast() with
ret set to NULL and
flags set to 0. It returns
SUCCESS if the stream can be converted into the form
requested, or FAILURE if the
conversion cannot be performed.
注: Although this function will not perform the conversion, some internal stream state *might* be changed by this call.
注: You must explicity compare the return value of this function with one of the constants, as described in php_stream_cast().
See also php_stream_cast() and
php_stream_is().