h6. [[URL_Fetcher]] h6(. » [[URL_Fetcher SWI Calls|SWI Calls]] h6((. » URL_EnumerateSchemes h2. URL_EnumerateSchemes h5. (SWI &83E08) Enumerate available fetch schemes. |_<^{width:3em}. Entry||| |<^.R0|\2<^.Flags:| ||<^.Bits 0-31|<^.All bits currently reserved (must be zero)| |<^.R1|\2<^.Context (0 for first call)| |_<^{width:3em}. Exit| |<^.R0|\2<^.Status flags (currently unused)| |<^.R1|\2<^.Context for next call (-1 if finished)| |<^.R2|\2<^.Pointer to read-only URL fetch scheme (if R1 is not -1)| |<^.R3|\2<^.Pointer to read-only help string (if R1 is not -1)| |<^.R4|\2<^.Protocol module SWI base (if R1 is not -1)| |<^.R5|\2<^.Protocol module version (*100, if R1 is not -1)| |\3<^.All other registers preserved| h4. Interrupts Interrupt state is undefined h4. Re-entrancy SWI is not re-entrant. h4. Use This call is used to discover which schemes are currently available to the URL module. It may be used, for example, to determine whether or not a client of the URL module may deal with a given URL (in combination with SWI [[URL_ParseURL]] to extract the scheme) and if not, pass it to the Acorn URI handler to see if anything else in the system can deal with it (see the Acorn URI Handler Functional Specification, 1215,215/FS). URL will not cope gracefully if the protocol module list is updated between calls to this SWI (you may get duplicate modules or miss some out).