Re: Help for use a DLL

Antonio Garcia Garcia wrote: 
I written an unit in Delphi that can identify the database. This part
was translated with tool h2pas.exe from Lazarus compiler.

function egdb_identify(directory: pchar; var egdb_type: TEGDB_TYPE;
max_pieces: integer);

It works fine, it returns the database type :-) 

If obviously _doesn't_ work fine. It won't even compile.

This is the original in header file.
EGDB_API int egdb_identify(char *directory, EGDB_TYPE *egdb_type, int
*max_pieces);

Go find the definition of the EGDB_API macro. You'll need it. Here's how I would declare that function in Delphi:

type
  PEgdbType = ^EGDB_TYPE;

function egdb_identify(directory: PAnsiChar; egdb_type: PEgdbType; max_pieces: PInteger): Integer; stdcall;

That "stdcall" on the end is written on the *assumption* that EGDB_API indicates that it uses the stdcall calling convention. You'll need to check that macro definition to be sure.

But I can't use this structure of functions to open the database :-(
I don't know how manage this record!

// The driver handle type
Pegdb_driver  = ^egdb_driver;
egdb_driver = record
	lookup: function (handle: Pegdb_driver;position: PEGDB_BITMAP;
                 color: integer; cl: integer): longint; cdecl;
	reset_stats: procedure (handle: Pegdb_driver);
	get_stats: function (handle: Pegdb_driver): PEGDB_STATS;
	verify: function (handle: Pegdb_driver): integer;
	close: function (handle: Pegdb_driver): integer;
	internal_data: pointer;
end;

Please, can anybody tell me how rewrite this in Delphi. Thanks a lot.

It's already in Delphi. You just posted it right here. You just need to add "cdecl" to the ends of the rest of the function-pointer declarations, like you have on the lookup field.

These are the original structures and functions in header file,
translated with tool h2pas.exe from Lazarus compiler.

/* The driver handle type */
typedef struct egdb_driver {
int (*lookup)(struct egdb_driver *handle, EGDB_BITMAP *position, int color, int cl);
void (*reset_stats)(struct egdb_driver *handle);
EGDB_STATS *(*get_stats)(struct egdb_driver *handle);
int (*verify)(struct egdb_driver *handle);
int (*close)(struct egdb_driver *handle);
void *internal_data;
} EGDB_DRIVER;

/* Open an endgame database driver. */
EGDB_API EGDB_DRIVER *egdb_open(EGDB_BITMAP_TYPE bitmap_type,
					  int pieces, int cache_mb,
					  char *directory,void (*msg_fn)(char *));


type
  TMsgProc = procedure(Param: PAnsiChar); cdecl;

function egdb_open(bitmap_type: Egdb_Bitmap_Type; pieces, cache_mb: Integer; directory: PAnsiChar; msg_fn: TMsgProc): PEgdb_Driver; stdcall;

Again, confirm that stdcall. The final parameter of this function is a procedure pointer. You'll need to declare a procedure (*not* a method of an object) that matches the signature above: one PAnsiChar parameter, and cdecl calling convention. You can name the procedure, and its parameter, whatever you want. Presumably, Egdb_Open will call that procedure to pass messages back to your program.

--
Rob
.