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OS_SetVarVal
Programmer's Reference Manuals
» Part 15 – SWI Calls
» OS
» OS_SetVarVal
OS_SetVarVal
(SWI &24)
| Entry | |
|---|---|
| R0 | Pointer to name |
| R1 | Pointer to value to set to |
| R2 | Length, or -1 to delete |
| R3 | Name pointer (0 for 1^st^ call) |
| R4 | Variable type |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Preserved |
| R2 | Preserved |
| R3 | New name pointer |
| R4 | Variable type |
Use
The purpose of this call is to write a variable value.
Notes
This SWI sets a variable’s value to that specified, or deletes the variable. The name may be wildcarded for deletion and update (using ‘*’ and ‘#’). Code variables will not be deleted unless R4 = 16. Literal strings do not need to be null terminated, as R2 is used for the length.
OS_ReadVarVal is marked as being re-entrant, which would allow it to re-enter the same code variable’s read code. No note is made about this in the PRM and the code variable example in the PRM calls OS_Byte 135 which has undefined re-entrancy!