Re: HELP mysql_server_init embedded in a DLL? - Derick Smith - com.mysql.lists.win32

4 messages in com.mysql.lists.win32Re: HELP mysql_server_init embedded i...

From	Sent On	Attachments
Derick Smith	27 Feb 2003 12:33
Gelu Gogancea	28 Feb 2003 04:40
Derick Smith	28 Feb 2003 11:09
Gelu Gogancea	02 Mar 2003 13:53

Subject:	Re: HELP mysql_server_init embedded in a DLL?
From:	Derick Smith (niag...@hotmail.com)
Date:	02/27/2003 12:33:22 PM
List:	com.mysql.lists.win32

I am posting this again, in hope that I will get a response.

I tried doing the following (see VB code below. I got this code from another site):

I get the same error message as if I was calling the DLL I created in C which calls mysql_server_init.

Is it impossible to call this function from VB or embedded in another DLL from VB? Can I only use the embedded mysql library in C or C++?

Thanks Eric

Public Declare Function mysql_server_init Lib "C:\mysql40\source\lib_release\libmysqld.dll" _ (ByVal argc As Long, _ ByVal argv As Byte, _ ByVal groups As Byte) As Long

Private Sub cmdmysq_server_init_Click() Dim argv(0) As Byte, groups(0) As Byte Dim i As Long argv(0) = Asc("0") groups(0) = Asc("0") i = mysql_server_init(0, argv, groups) End Sub

To: mys...@lists.mysql.com, win...@lists.mysql.com Subject: mysql_server_init embedded in a DLL? Date: Wed, 26 Feb 2003 14:34:28 +0000

Hi!

I am trying to create a DLL that will hide embedded mySQL functions for use with VB. I am using mysqlserver.lib. I am able to compile and execute the following code. This has to be done in C because VB is too slow :-(

If mysql_server_init function is run in the DLL from Visual Basic. I get the following error message: "..referenced memory at "0x000000". The memory could not be read".

Without the mysql_server_init function it will run correctly. It will also run correctly when this is compiled as a .lib file linked to a C program.

Is it possible to embed mysql_server_init in a DLL? (So the DLL can be used in VB)

Thanks in advance for any responses.

Thanks Eric

header1.h

#define GPAPI __stdcall

header2.h

typedef unsigned long DBS; #define NULLDBS (DBS)0

api.c

GPAPI DBS dbNewSet (char * basedir, char * datadir, char * dbname) { return NewSet(basedir,datadir,dbname); }

newset.c

extern DBS NewSet(char * basedir, char * datadir, char * dbname) { DBSET* pSet = CreateSet(); char *args[3]; char strArgs[3][1024]; int iRtn; int argc = 3;

strcpy(strArgs[0],"this_program"); sprintf(strArgs[1],"--basedir=%s",basedir); sprintf(strArgs[2],"--datadir=%s",datadir); args[0]= strArgs[0]; args[1]= strArgs[1]; args[2]= strArgs[2];

/* If I comment out this line of code, the DLL will run correctly. If mysql_server_init function is run in the DLL. I get the following error message: "..referenced memory at "0x000000". The memory could not be read" */ iRtn = mysql_server_init(3, args, server_groups);

if (pSet ==0 ) return NULLDBS; memset(pSet, 0, sizeof(DBSET)); /* Zero the structure. */ pSet->size = sizeof(DBSET);/* Assign structure size. */ pSet->magic = DBS_MAGIC; /* Assign magic number. */

return (DBS)(void*)pSet; }