Hi all,

When you use the MySQL client, you have to call myslq_library_init to initialise the library, and mysql_library_end to de-initialize it again.

When the library is dynamically loaded using mysqlXXdyn.pp, shall I call these functions automatically? Or should we leave it to the programmer? (I'm in favour of doing it automatically)

But when the library is linked in statically? Add these functions to the initialize and finalize sections of the unit mysqlXX.pp? Or should we leave these calls to the programmer? (In this case I would let the programmer do this)

Does this proposal make sense?

Joost.

In our previous episode, Joost van der Sluis said:

No real strong opinion, BUT if you don't do it, if the prototype changes, you can work around without requiring a new version of FPC.

(e.g. a certain MS version of the dll turns out to accidentally have decorated versions).

But when the library is linked in statically? Add these functions to the initialize and finalize sections of the unit mysqlXX.pp? Or should we leave these calls to the programmer? (In this case I would let the programmer do this)

I would too.

Are there any options to these calls ?

If there are, it is a no, I think ?

Michael.

Op woensdag 03-12-2008 om 13:09 uur [tijdzone +0100], schreef Michael Van Canneyt:

Didn't thought about that. And yes, there are options. They are in practice only used with the embedded-mysql version. And iven in that case I guess they are rarely used:

"The argc and argv arguments are analogous to the arguments to main(), and enable passing of options to the embedded server. For convenience, argc may be 0 (zero) if there are no command-line arguments for the server. This is the usual case for applications intended for use only as regular (non-embedded) clients, and the call typically is written as mysql_library_init(0, NULL, NULL)."

So, what to do?

Joost.

....

So, what to do?

There is another option. You can keep track if the user called it. If the user did not call it, but any other function is called, then call it yourself

procedure MaybeCallInit;
begin
  if InitCalled then exit;
  DoCallInit(0, nil, nil);
  InitCalled := True;
end;

Well it will be more complex, as if this is in a multi threaded environment you have to keep track for each Thread. That is unless the library is loaded and initialized before any threads are spawned...

Best Regards
Martin

Op woensdag 03-12-2008 om 15:06 uur [tijdzone +0000], schreef Martin Friebe:

That's not possible, since the user can not call it before the library is loaded. And this code should be placed in the code to load the library.

Besides, the init is not the problem, because MySQL will call it automatically. But the finalization of the library, that's the real point. (If it's not called, that introduces mem-leaks)

But to call the finalization and not the initialization is pretty bad design, imho.

Well it will be more complex, as if this is in a multi threaded environment you have to keep track for each Thread. That is unless the library is loaded and initialized before any threads are spawned...

These calls have to be called before all other threads are spawned. Or else you're in trouble.

Joost.

Op woensdag 03-12-2008 om 18:39 uur [tijdzone +0100], schreef Joost van der Sluis:

Because the library-handle is also reference counted it's quite difficult for the programmer to call these functions at the right moment.

So I've decided to call them automatical, and add the parameters to the InitialiseMySQL procedure, so that they are passed to the library-init function.

Joost.