YENGtry
From OpenSimulator
try, catch and finally allow to handle some runtime exceptions without getting the script killed.
- on the try block we place the code we want to run protected.
- on a catch block we place code to handle the exception
- on the finally block we place code that should run always.
- throw keyword allows a catch to reissue the exception, so the engine handles it normally
a try block must be follow by at one catch or two of the following catch types, one finally block or all of those
at this time there are only 2 types of cache blocks
to catch any available exception:
catch(exception ex) { }
to catch script related exceptions
catch(scriptexception ex) { }
in both cases particular exception must be looking to the message.
the catch blocks types are check by their order in source, if both needed scriptexception should be first.
Note that scriptexception is a type of exception, so being one exception. It will trigger catch(exception) if that is the only one, or is before the scriptexception one
There can not be any llResetScript or osResetAllScripts inside any of this blocks. script will compile but fail with a severe runtime error
there are a few auxiliar functions
string yExceptionMessage(exception ex)
returns a string with the message of the exception ex
string yExceptionTypeName(exception ex)
returns a string with system name of the exception. scriptexception will return ScriptException
so catch(scriptexception ex) could be
catch(exception ex)
{
if(yExceptionTypeName(ex) == "ScriptException")
{
...
}
}
Examples
silly example
touch_start(integer nn)
{
integer a = 0;
try
{
llSay(0,"try");
float c = 1 / a;
}
catch(scriptexception ex)
{
if(yExceptionMessage(ex) == "Division by Zero")
llSay(0,"Where did you learn math?");
else
throw;
}
finally
{
llSay(0,"finaly");
}
}
detect no ossl permission
touch_start(integer nn)
{
try
{
key agent = llDetectedKey(0);
osForceOtherSit(agent);
}
catch(scriptexception ex)
{
string message = yExceptionMessage(ex);
if(osStringStartsWith(message,"ossl permission error", TRUE))
llSay(0,"You need to enable osForceOtherSit on osslEenable.ini");
else
throw;
}
}
