URL_EnumerateSchemes (changes)
Showing changes from revision #1 to #2:
Added | Removed | Changed
URL_Fetcher
» SWI Calls
» URL_EnumerateSchemes
URL_EnumerateSchemes
(SWI &83E08)
| Entry | ||
|---|---|---|
| R0 | Flags: | |
| Bits 31-0 | Reserved (0) | |
| R1 | Context (0 for first call) | |
Enumerate available fetch schemes.
| R0 | |||
| All bits currently reserved (must be zero) | |||
| R3 | Pointer to read-only help string (if R1 is not -1) | ||
| R4 | Protocol module SWI base (if R1 is not -1) | ||
| R5 | Protocol module version (*100, if R1 is not -1) | ||
| All other registers preserved | |||
| SWI is not re-entrant | |||
| Interrupt status is undefined | |||
| Exit | ||
|---|---|---|
| R0 | Status flags (currently unused) | |
| R1 | Context for next call (-1 if finished) | |
| R2 | Pointer to read-only URL fetch scheme (if R1 is not -1) | |
| R3 | Pointer to read-only help string (if R1 is not -1) | |
| R4 | Protocol module SWI base (if R1 is not -1) | |
| R5 | Protocol module version (*100, if R1 is not -1) | |
| All other registers preserved | ||
Interrupts
Interrupt state is undefined
Re-entrancy
SWI is not re-entrant.
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 AcornURL_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).
Social
and
ROOL Store
Buy RISC OS Open merchandise here, including SD cards for Raspberry Pi and more.