id	summary	reporter	owner	description	type	status	priority	component	version	resolution	keywords	cc
228	To define behaviour of new-delete on empty structs	mlbrooks	Peter A. Buhr <pabuhr@…>	"
{{{
struct thing{};
void ?{}( thing & ) {
    printf(""ctor\n"");
}
void ^?{}( thing & ) {
    printf(""dtor\n"");
}

int main() {
    thing * one = new();
    delete(one);
}
}}}

Current: Outputs ""ctor,"" but not ""dtor.""

An explanation of current behaviour:
- program calls new with return type thing
- new calls malloc with sizeof(thing), which is zero
- malloc returns 0p when asked for zero bytes
- new calls the thing constructor with argument *0p
- new returns 0p as the requested object, which populates main variable one
- program calls delete with argument one, which is 0p
- delete of 0p is a no-op

We learned that sizeof( struct{} ) is 0 in C and 1 in C++.  It is currently 0 in CFA.

One option discussed:
- sizeof(struct{}) is 0
- new always calls malloc, requesting min(1, sizeof(T)) bytes
- new always calls constructor with a nonzero malloc result, except when malloc is unable to allocate
- new skips the constructor call when malloc is unable to allocate
- delete always calls free
- delete does not call a destructor when the argument is 0p
- delete calls a destructor when the argument is not 0p
- all constructor and destructor calls use a non *0p argument

Another option discussed:
- sizeof(struct{}) is 0
- new always calls malloc, requesting exactly sizeof(T) bytes
- new does not call a constructor when the type's size is nonzero and malloc returns 0p
- new calls a constructor with argument *0p when the type's size is zero
- delete always calls free
- delete does not call a destructor when the type's size is nonzero and the argument is 0p
- delete calls a destructor with argument 0p when the type's size is zero
- constructor and destructor calls use a 0p argument for {}-structs
"	enhancement	closed	minor	libcfa	1.0	fixed