On Tuesday, 3 December 2013 at 12:31:16 UTC, John Colvin wrote:
On Tuesday, 3 December 2013 at 10:57:51 UTC, Chris wrote:
I have a C module that dynamically allocates memory for a
string like so:
char *result = (char*)malloc(length + 1); // 'length' has been
calculated
When I call it from D (via extern (C)), is it ok to free it
from there like so:
void callFunction() {
auto result = callToCFunction(); // Returns above *result
// ...
std.c.stdlib.free(result);
}
The problem is that, as it is now, *result is allocated in a
different place in the C module (not in "callToCFunction())
and cannot be freed before D has called it.
If D cannot free it in this way, I'll have a serious memory
leak and I'll have to rewrite the existing C module (which is
probably better given the awkward situation above).
You should be fine to free in that way as long as you haven't
done anything crazy like separately static linking libc.
core.stdc.stdlib; is the correct module to use, std.c.* only
exist for backwards compatibility.
Ok. Thanks for the answer. std.c.stdlib.free() is mentioned on
the "How to interface to C" page
(http://dlang.org/interfaceToC.html). So maybe that needs an
update.
