Re: Where to find connect declaration of this mysql instace - C / C++ / MFC Discussion Boards

Re: Where to find connect declaration of this mysql instace

Richard MacCutchan7-Jan-23 21:06

Richard MacCutchan

7-Jan-23 21:06

You need https://dev.mysql.com/doc/connector-cpp/8.0/en/[^]; jdbc is the Java driver.

Re: Where to find connect declaration of this mysql instace

coco2438-Jan-23 1:27

coco243

8-Jan-23 1:27

Yes, I have installed Connector C++ 8.0, in the link below it is explained that Conector C++ 8.0 supports "legacy C++ API based on the JDBC4",
and there is an exemplified code where appear the "connect" statement, and I am not able to understand where is defined to see it's functions or more
details.

https://dev.mysql.com/doc/dev/connector-cpp/8.0/jdbc_ref.html

Thank you.

Re: Where to find connect declaration of this mysql instace

Richard MacCutchan8-Jan-23 1:37

Richard MacCutchan

8-Jan-23 1:37

I think you will need to search the documentation, or use the MySQL forum.

Re: Where to find connect declaration of this mysql instace

coco2438-Jan-23 1:58

coco243

8-Jan-23 1:58

When I installed Connector C++, there were unziped the headers that contains declarations of classes and functions.
I suposed that is logical to find the declaration of these functions, clases constructors etc on those .h files.

I found connect declaration in driver.h file:

C++

class CPPCONN_PUBLIC_FUNC Driver
{
protected:
  virtual ~Driver() {}
public:
  // Attempts to make a database connection to the given URL.

  virtual Connection * connect(const sql::SQLString& hostName, const sql::SQLString& userName, const sql::SQLString& password) = 0;

  virtual Connection * connect(ConnectOptionsMap & options) = 0;

  virtual int getMajorVersion() = 0;

  virtual int getMinorVersion() = 0;

  virtual int getPatchVersion() = 0;

  virtual const sql::SQLString & getName() = 0;

  virtual void setCallBack(sql::Fido_Callback &cb) = 0;

  virtual void setCallBack(sql::Fido_Callback &&cb) = 0;

  virtual void threadInit() = 0;

  virtual void threadEnd() = 0;
};

And I found that the connection type(or class) of the connect defined in the connection.h file:

class CPPCONN_PUBLIC_FUNC Connection
{
  /* Prevent use of these */
  Connection(const Connection &);
  void operator=(Connection &);
public:

  Connection() {};

  virtual ~Connection() {};

  virtual void clearWarnings() = 0;

  virtual Statement *createStatement() = 0;

  virtual void close()  = 0;

  virtual void commit() = 0;

  virtual bool getAutoCommit() = 0;

  virtual sql::SQLString getCatalog() = 0;

  virtual Driver *getDriver() = 0;

  virtual sql::SQLString getSchema() = 0;

  virtual sql::SQLString getClientInfo() = 0;

  virtual void getClientOption(const sql::SQLString & optionName, void * optionValue) = 0;

  virtual sql::SQLString getClientOption(const sql::SQLString & optionName) = 0;

  virtual DatabaseMetaData * getMetaData() = 0;

  virtual enum_transaction_isolation getTransactionIsolation() = 0;

  virtual const SQLWarning * getWarnings() = 0;

  virtual bool isClosed() = 0;

  virtual bool isReadOnly() = 0;

  virtual bool isValid() = 0;

  virtual bool reconnect() = 0;

  virtual sql::SQLString nativeSQL(const sql::SQLString& sql) = 0;

  virtual PreparedStatement * prepareStatement(const sql::SQLString& sql) = 0;

  virtual PreparedStatement * prepareStatement(const sql::SQLString& sql, int autoGeneratedKeys) = 0;

  virtual PreparedStatement * prepareStatement(const sql::SQLString& sql, int* columnIndexes) = 0;

  virtual PreparedStatement * prepareStatement(const sql::SQLString& sql, int resultSetType, int resultSetConcurrency) = 0;

  virtual PreparedStatement * prepareStatement(const sql::SQLString& sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) = 0;

  virtual PreparedStatement * prepareStatement(const sql::SQLString& sql, sql::SQLString columnNames[]) = 0;

  virtual void releaseSavepoint(Savepoint * savepoint) = 0;

  virtual void rollback() = 0;

  virtual void rollback(Savepoint * savepoint) = 0;

  virtual void setAutoCommit(bool autoCommit) = 0;

  virtual void setCatalog(const sql::SQLString& catalog) = 0;

  virtual void setSchema(const sql::SQLString& catalog) = 0;

  virtual sql::Connection * setClientOption(const sql::SQLString & optionName, const void * optionValue) = 0;

  virtual sql::Connection * setClientOption(const sql::SQLString & optionName, const sql::SQLString & optionValue) = 0;

  virtual void setHoldability(int holdability) = 0;

  virtual void setReadOnly(bool readOnly) = 0;

  virtual Savepoint * setSavepoint() = 0;

  virtual Savepoint * setSavepoint(const sql::SQLString& name) = 0;

  virtual void setTransactionIsolation(enum_transaction_isolation level) = 0;

  /* virtual void setTypeMap(Map map) = 0; */
};

Maybe this operator:

C++

void operator=(Connection &);

, tries to tell something that I don't understand I will keep digging to understand something.

Thank you,

Re: Where to find connect declaration of this mysql instace

Richard MacCutchan8-Jan-23 3:04

Richard MacCutchan

8-Jan-23 3:04

coco243 wrote:
Maybe this operator:

It is a simple overload of the assignment operator in C++. But is has very little to do with your question. The method you need to use is at the beginning:

C++

virtual Connection * connect(const sql::SQLString& hostName, const sql::SQLString& userName, const sql::SQLString& password) = 0;

Re: Where to find connect declaration of this mysql instace

coco2438-Jan-23 5:53

coco243

8-Jan-23 5:53

Yes, but I don't know where to find the definition of this method.
I don't find the code behind it.

Re: Where to find connect declaration of this mysql instace

Richard MacCutchan8-Jan-23 22:28

Richard MacCutchan

8-Jan-23 22:28

That is the definition of the method. You just need to code it with all the parameters filled in as necessary.

Re: Where to find connect declaration of this mysql instace

coco2439-Jan-23 10:21

coco243

9-Jan-23 10:21

I don't see where I am misunderstand the things but it appears to me as a declaration of a method.

For example if we have a class defined like that:

C++

class point{
public:
int x,y;
void set (int val_x, int val_y);     // here the method declaration   
};

void point::set( int val_x, int val_y)   // here the method definition
                                         
	x = val_x;
	y = val_y;
	
}


void main()
{
	point p1;

	p1.set(10,2);    // here te call of the method

}

In the set method I have the parameters val_x and val_y, and I see in the definition of the set method the processes that implies val_x, and val_y,
I see that val_x is attributed to x and so over, but in the connect method I don't see where hostName, userName and password are used.
That it what I want to understand.

Thank you,

Re: Where to find connect declaration of this mysql instace

Richard MacCutchan9-Jan-23 21:50

Richard MacCutchan

9-Jan-23 21:50

coco243 wrote:
in the connect method I don't see where hostName, userName and password are used.

Why do you need to? All you really need to understand is that the C++ library will use those details to create an actual connection to the MySQL driver, and from there to the actual database server.

Re: Where to find connect declaration of this mysql instace

coco24310-Jan-23 4:10

coco243

10-Jan-23 4:10

I had figured that if I know how this function is defined, I can extract more information about the conection, status of conection and other things that I am not aware, in addition I wanted to have a better overview on the subject.

modified 10-Jan-23 10:25am.

Re: Where to find connect declaration of this mysql instace

Richard MacCutchan10-Jan-23 5:29

Richard MacCutchan

10-Jan-23 5:29

All such information would normally be found in the documentation. And after searching the MySQL pages I think you need to look at https://dev.mysql.com/doc/c-api/8.0/en/[^]. it is titled "C APIO", but I assume it works just as well with the C++ driver.

Re: Where to find connect declaration of this mysql instace

coco24310-Jan-23 6:03

coco243

10-Jan-23 6:03

Normaly this information should be in the installation folders of the C++ connector, in the headers files, and some of it, it is, but I just don' t know where to find definition of those methods, any way I supose that I will succed finally, but it would have been intresting to know how this method were coded. Or maybe those would be an waste of time or to complicate for my knowledge level.

Re: Where to find connect declaration of this mysql instace

Richard MacCutchan10-Jan-23 6:42

Richard MacCutchan

10-Jan-23 6:42

I gave you a link to the API in my previous message, you need to go and study it.

Re: Where to find connect declaration of this mysql instace

coco24310-Jan-23 8:12

coco243

10-Jan-23 8:12

Ok, tank you

Re: Where to find connect declaration of this mysql instace

markkuk10-Jan-23 2:27

markkuk

10-Jan-23 2:27

The legacy API documentation is in Connector/C++ 1.1 Developer Guide[^] even if you use version 8 of the connector. Options for MySQLDriver::Connect() are explained here: https://dev.mysql.com/doc/connector-cpp/1.1/en/connector-cpp-connect-options.html[^]

Re: Where to find connect declaration of this mysql instace

coco24310-Jan-23 4:11

coco243

10-Jan-23 4:11

Thank you for the link.

Re: Where to find connect declaration of this mysql instace

RedDk8-Jan-23 9:12

RedDk

8-Jan-23 9:12

coco243 wrote:
I saw in an example

If you look here: https://dev.mysql.com/doc/connector-j/8.0/en/connector-j-reference-jdbc-url-format.html[^]
you can see why Richard thinks just a link to another user forum doesn't help anybody. Especially when, in the phrasing of the question, there is some symmantic disconnect on parade. For all Christendom to see.

You might type in using your keyboard what your eyes are referencing now.

dll access violation with Excel 32 / 64 bits

Danilo Lemos 20216-Jan-23 1:30

Danilo Lemos 2021

6-Jan-23 1:30

Hi,

I built a function library (dll) in MS-Visual Studio 2022 using C/C++, to be accessed directly from Excel cells via VBA code.

When I call the dll in the 32-bit version of Microsoft 365 Excel, no error occurs. But when I compile the dll for x64 and run it from the 64-bit version, an access violation occurs in the function arguments.

Summarizing the project in a single function:

---------------------------------------------------------------
.cpp file:

extern "C"
{
    __declspec(dllexport) double __stdcall fA(INT64&);
}

double __stdcall fA(double& a) // causes an exception in 64 bits mode
{
    return a;
}
-------------------------------------------------------------

VBA da planilha Excel:

Declare PtrSafe Function fA _
Lib "C:\dll64\dll64.dll" (ByRef a As Double) As Double

-------------------------------------------------------------

Re: dll access violation with Excel 32 / 64 bits

Victor Nijegorodov6-Jan-23 5:49

Victor Nijegorodov

6-Jan-23 5:49

Why did you declared it as

C++

double __stdcall fA(INT64&);

not as

double __stdcall fA(double&);

Linker error when adding Ole to my application, what am I missing?

charlieg4-Jan-23 16:15

charlieg

4-Jan-23 16:15

I'm trying to get some code to run to work around another issue, and for the life of me, I cannot make the VS2008 linker happy.
This is for a smart device, Windows Embedded Compact 7, but I think the target is only a symptom. I've tried this against 3 different SDKs for VS2008 as well as EVC++ (going way back) and two different SDKs - all have the same issue.

I need the application to run OLE. So, I created a very simple dialog app - think default code base, C++. It compiles and links. I then add one call: "OleInitialize(0);" and I get this:

Quote:
1>Linking...
1>OleTest.obj : error LNK2019: unresolved external symbol OleInitialize referenced in function "public: virtual int __cdecl COleTestApp::InitInstance(void)" (?InitInstance@COleTestApp@@UAAHXZ)

You can say I need to add an input to the linker line for ole32.lib, but it still fails. Oddly, VS2008 shows that I've inherited these from the solution. Of course the desktop links fine.

Any random or "oh crap, yeah, I had that problem" ideas? It's almost as if the ole32.lib doesn't have OleInitialize. I could believe that for one SDK but not 5.

Charlie Gilley

“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759

Has never been more appropriate.

Re: Linker error when adding Ole to my application, what am I missing?

CPallini4-Jan-23 22:14

CPallini

4-Jan-23 22:14

As rough guess, the linker is not able to find the ole32 library for the embedded platform target (the reason I really don't know).

"In testa che avete, Signor di Ceprano?"
-- Rigoletto

Re: Linker error when adding Ole to my application, what am I missing?

charlieg6-Jan-23 5:07

charlieg

6-Jan-23 5:07

Well that's the obvious thing, but for the life of me I don't know why. I have other code that links with a few non-default libraries, and these are found fine. I searched my SDKs, and all of them have the library in question.

Very weird.

Charlie Gilley

“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759

Has never been more appropriate.

Re: Linker error when adding Ole to my application, what am I missing?

Randor 5-Jan-23 16:41

Randor

5-Jan-23 16:41

Hi,

Have you tried using CoInitializeEx?

Determining Supported COM APIs (Windows CE 5.0) | Microsoft Learn

Re: Linker error when adding Ole to my application, what am I missing?

charlieg6-Jan-23 10:17

charlieg

6-Jan-23 10:17

Give that man a cigar!

It had to be something stupid like that - I didn't pick up on that because if I hit :: - OleInitialize is actually in the popup. I guess it's in a header file but not in the binary.

Thank you

Charlie Gilley

“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759

Has never been more appropriate.

Re: Linker error when adding Ole to my application, what am I missing?

Randor 6-Jan-23 10:40

Randor

6-Jan-23 10:40

Charlie,

charlieg wrote:
I guess it's in a header file but not in the binary.

Thank you

You are welcome.

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