Object destructors can be tricky in a GC'd language. It looks like you're
accessing a deallocated pointer in your destructor. Order of
collection/destruction is not guaranteed.
Bane Wrote:
> Following code will freeze app on std.gc.fullCollect(), when sqlite3_close()
> in destructor is called. If destructor is called manualy, everything goes ok.
>
> Is it a bug, and if is, with what? It behaves same on winxp64 and centos5.2
> using dmd 1.30 and sqlite 3.6.5 or 3.6.19 statically import lib. Libraries
> are tested so I do not suspect problem lies in them (they are compiled with
> dmc/gcc using full threading support).
>
> Is this some problem with GC or, more likely, my knowledge? I would
> appreciate some clarification, this thing took me a lot of hours to track.
>
> Thanks,
> Bane
>
> ==========================================
>
>
> import std.stdio;
> import std.gc;
> import std.string;
> import std.thread;
>
> pragma(lib, "sqlite3.lib");
> const int SQLITE_OK = 0; // Successful result.
> struct sqlite3 {}
> extern(C) int sqlite3_open (char* filename, sqlite3** database);
> extern(C) int sqlite3_close(sqlite3* database);
>
> class SQLite {
> sqlite3* h;
> this(){
> assert(sqlite3_open(toStringz(":memory:"), &h) == SQLITE_OK);
> }
> ~this(){
> writefln("~this start"); // to help debug
> assert(sqlite3_close(h) == SQLITE_OK);
> writefln("~this stop"); // to help debug
> }
> }
>
> class T : Thread {
> int run(){
> SQLite s = new SQLite;
> // if next line is uncommented then app wont freeze
> // delete s;
> return 0;
> }
> }
>
> void main(){
> while(true){
> T t = new T;
> t.start;
> writefln(Thread.nthreads);
> if(Thread.nthreads > 10)
> fullCollect; // this will freeze app
> }
> }
