Unmanaged lib in managed executable causing managed exceptions

Question

Hi everyone, I'm having a problem with mixing managed and unmanaged code. I have created two projects under a single solution in Visual Studio 2008 under Vista x64 SP1. One of them does not have CLR support and is a static library. My second project is compiled as an executable with CLR enabled. It depends on the first static library, and passes WinForms events to it.

When I start the application without debugging, I get an exception, I put the info that I get from the exception here: http://pastebin.com/f46ad1211.

Here is the code of the unmanaged lib that is run:

void manager::init() // <-- Called from the .exe project
{
    this->log.open("C:\\development\\log.txt");
    this->storage = storage_manager(&(this->log), &(this->settings));
    this->storage.load_settings();
}

&

void storage_manager::load_settings()
{
    this->error_check(sqlite3_open("settings.db", &(this->db_settings_p)));
    sqlite3_stmt* read_settings;
    this->error_check(sqlite3_prepare_v2(this->db_settings_p, "SELECT name, value FROM settings", 1024, &read_settings, NULL));

    int step_code;
    std::string name;
    std::string value;
    while(true)
    {
     step_code = sqlite3_step(read_settings);
     if(step_code == SQLITE_DONE)
     {
      break;
     }
     else if(step_code == SQLITE_ROW)
     {
      name = std::string(reinterpret_cast<const char*>(sqlite3_column_text(read_settings, 0)));
      value = std::string(reinterpret_cast<const char*>(sqlite3_column_text(read_settings, 1)));
      (*(this->settings))[name] = value;

     }
     else
     {
      this->error();
     }
    }
    sqlite3_reset(read_settings);
    sqlite3_finalize(read_settings);
}

&

void storage_manager::error_check(int rc)
{
    if(rc)
    {
     this->error();
    }
}
void storage_manager::error() //Sure of error
{
    std::string error_msg;
    error_msg = "Storage Manager: SQLite Error (";
    error_msg += sqlite3_errcode(this->db_p);
    error_msg += ") - ";
    error_msg += sqlite3_errmsg(this->db_p);
    this->log->write(error_msg.c_str(), error_msg.length());
    this->log->flush();
}

I can't see why I'm getting a managed (System.BlahBlahBlah) exception in an unmanaged library. Is there any way to get the two to be totally separate?

Answer 1

The underlying exception is actually a Windows exception that the CLR is apparently turning into a CLR exception for you. You have an access violation. What you should be able to do is, in Visual Studio, head to Debug > Exceptions and break on acess violations. This should let you drop in and see where in the native code it's gone all horribly wrong and start diagnosing the issue.