FreeTDS Development Group

[Brian Bruns <camber AT umcc.ais.org>]

Take a look at the tds_client_msg() function it does pretty much what you
want (we use it for results pending messages, which are client side only
messages). check token.c at line 909 or so for a sample invocation.

Brian

On Mon, 24 Jan 2000, Geoff Winkless wrote:

> Ok, here's a tricky one.
> 
> I've implemented a check in read.c:tds_read_packet for a negative return
> from the read() function. This catches a disconnected socket correctly.
> 
> I thus decided to send an error to the error handler - but since that
> expects a msg_info struct, (which we obviously don't get back from the
> server, since the server is disconnected!) I build one on the fly...
> 
> So we have:
> 
>     if (len < 0) {
> 
>       /* now we need to pass a fake message back to the error handler. */
>       tds->msg_info->msg_number = 10018; /* is there a define for this??? */
>       tds->msg_info->message="The connection was closed";
>       tds->msg_info->msg_state=0;
>       tds->msg_info->msg_level=9;
>       tds->msg_info->priv_msg_type = 0;
>       tds->msg_info->server=NULL;
>       tds->msg_info->proc_name=NULL;
>       tds->msg_info->line_number = 0;
>       if (tds->parent) {
>         fprintf (stderr, "tds->parent is valid. Calling err_handler\n");
>         g_tds_err_handler(tds->parent);
>       } else {
>         fprintf (stderr, "tds->parent is null\n");
>         tds_free_msg(tds->msg_info);
>       }
> 
> 
> Now I'm using dblib so g_tds_err_handler gets set to
> dblib_handle_err_message.
> 
> If I gdb-break my program at the point above, I can do the following:
> 
> (gdb) print dblib_handle_err_message
> $2 = {int (void *)} 0x4001571c <dblib_handle_err_message>
> (gdb) print g_tds_err_handler
> $3 = (int (*)()) 0x4001571c <dblib_handle_err_message>
> 
> Now if I allow this call (g_tds_err_handler(tds->parent)) to continue the
> program SIGSEGVs - it appears to be calling some random address in data
> space.
> 
> However if I call dblib_handle_err_message (tds->parent) instead, the
> program runs correctly.
> 
> Any thoughts?
> 
> Geoff
> 
>