On 2010-09-26 10:06:33 -0400, "Simen kjaeraas" <simen.kja...@gmail.com> said:
Tom Kazimiers <2voo...@gmx.de> wrote:
Hi,
a file reading class of mine can be constructed with a filename as
parameter. It instantiates a new std.stream.File (without the passed
file name and closes it when opened within the destructor. The last part
is where things are getting unclear for me. On the "file.isOpen()" call
in the destructor a segmentation fault occurs. What is the problem with
that?
Likely, it is this[1]:
"[T]he order in which the garbage collector calls destructors for
unreference objects is not specified. This means that when the garbage
collector calls a destructor for an object of a class that has members
that are references to garbage collected objects, those references may
no longer be valid. This means that destructors cannot reference sub
objects."
[1]: http://digitalmars.com/d/2.0/class.html#destructors
That's it indeed, but I'll add that it's the File struct that is at
fault. See this bug:
<http://d.puremagic.com/issues/show_bug.cgi?id=4624>
To make it short: when the File struct is located somewhere in the GC
heap (like inside a class), File's destructor is buggy when a file is
open. The only workaround I can think of is to call close() or detach()
on the file struct before the garbage collectors kicks in (doing it in
the destructor of your class is already too late, it must be done
before the destructor gets called).
In fact, it's generally a good idea to not wait for the GC to collect
your objects before closing files, because waiting for the GC could
take an indeterminate amount of time and leave files open for a long
time (the GC only runs when needed).
--
Michel Fortin
michel.for...@michelf.com
http://michelf.com/
