Subj : can't understand difference in vars
To   : johny5@ngs.ru
From : Brendan Eich <brendan@meer.net>
Date : Tue Mar 23 2004 11:36 am

You want this instead:

JSBool MakeThree(JSContext *cx, JSObject *obj, uintN argc, jsval *argv,
jsval *rval)
{
     return JS_NewNumberValue(cx, 3, rval);
}

As Marcello's followup points out, the internal representation of 3 
should be an int jsval, not a double jsval.  Calling JS_NewDouble to 
make a jsdouble allocated on the GC heap, just to contain a small 
integer, is wasteful, besides not resulting in the desired operation.

Always use JS_NewNumberValue, as it can optimize numbers into ints 
instead of doubles where possible.

/be

.