Safeguarding the past, present and future of RISC OS for everyone
OS_GenerateError
OS SWI Calls
» OS_GenerateError
OS_GenerateError
(SWI &2B)
| Entry | |
|---|---|
| R0 | Pointer to error block |
| Exit | |
|---|---|
| R0 | Only returns (with V flag on) if X was set |
Use
The purpose of this call is to generate an error and invoke the error handler.
Notes
The X form may appear to be completely useless as it is effectively a no-op!
However, it has at least 3 uses
- Terminated string conversion in BASIC
- Detecting whether OS_CallASWI is available by calling OS_GenerateError via OS_CallASWI and seeing what comes back in R0
- Force a callback to occur
See also
Social
Follow us on
and
and
ROOL Store
Buy RISC OS Open merchandise here, including SD cards for Raspberry Pi and more.