DESCRIPTION¶
This is a privileged function, only to be used in the master object or in the simul_efun object.
It changes the result of this_object(E) in the using function, and the result of previous_object(E) in functions called in other objects by call_other(E)/apply(E)/funcall(E). Its effect will remain till there is a return of an external function call, or another call of set_this_object(E). While executing code in the master object’s program or the primary simul_efun object’s program, set_this_object(E) is granted even if this_object(E) is altered by set_this_object(E). This does not apply to functions inherited from other programs.
Use it with extreme care to avoid inconsistencies. After a call of set_this_object(E), some LPC-constructs might behave in an odd manner, or even crash the system. In particular, using global variables or calling local functions (except by call_other) is illegal and actively prevented.
Allowed are call_other(E), map functions, access of local variables (which might hold array pointers to a global array), simple arithmetic and the assignment operators.
Limit
It is currently not possible to directly restore the original current object. So instead of writing:
object me = this_object();
set_this_object(that);
<some code>
set_this_object(me);
<more code>
one has to use a workaround::
private void doit (object that) {
set_this_object(that);
<some code>
}
funcall(#'doit, that);
<more code>
Some people would consider this a feature.
HISTORY¶
- changed (3.2.10) – actively prevents references to global variables and function calls by address while
set_this_object(E) is in effect.