OnExit
Syntax
| Syntax legend | |
|---|---|
| < ... > | item |
| [ ... ] | optional |
| ( ... ) * | 0 or more times |
| ( ... ) + | 1 or more times |
Begin
- [ <main code> ]
[OnExit
- [ <exit code> ]
]
End
Description
The OnExit statement can be used between the Begin and End statements in the Process or Function. When the Program, Process or Function is killed, the exit code starts. This can be easily used to free any memory used by the exiting process.
Notes
Be advised, Frame statements are interpreted as Frame(0) statements, to ensure exit code of the killed instance finishes the same frame as the instance is killed. Code like
Loop frame; End
will cause Bennu to freeze, as frame(0); doesn't allow switching to another instance.
Example
Basics
import "mod_proc"
import "mod_say"
Process proc1()
Begin // Start the main code part of the process
say("Proc created");
// Run indefinitely (or until killed)
Loop
frame;
End
OnExit // Start the exit code of the process
say("Proc killed!");
End
Function int func1()
Begin // Start the main code part of the function
say("Func created");
return 0;
OnExit // Start the exit code of the function
say("Func killed!");
End
Process Main()
Private
int p;
Begin // Start the main code part of the main process
p = proc1(); // create new instance of proc1
func1();
say("Main is here");
OnExit // Start the exit code of the main process
say("Main is killed");
signal(p,S_KILL);
say("Main is at the end");
End
Used in example: loop, end, process, function, frame, say()
Resulting console messages:
Proc created Func created Func killed! Main is here Main is killed Main is at the end Proc killed!
Resource cleanup
A good use for this is the following:
Process ship()
Begin
graph = map_new(20,20,8);
Loop frame; End
OnExit
map_unload(0,graph);
End
Used in example: map_new(), map_unload(), graph, loop, frame, end