Memory Leak

I wrote a program using VC++.
I use the library files (vld.h) to detect the memory leak problem.
I face memory leak problem.
Here is the sample.

char * a;

UCHAR b[100];
.
.
.

a = (char *) b;

std::string c = std::string(a);

Can anyone help me?

Thanks.

What is happening in between those lines ( the .... s )

In between the lines, I actually access mysql such as select statement or update statement.

Like
- SQLBindCol(hStmt, 1, SQL_C_CHAR, ....

Thanks

When Ever use a Pointer in your Program try to use new to Allocate Memory to your pointer and after Finishing your Work use Delete to free allocated memory.
Thanx

Quote:

---

Originally Posted by thl

I wrote a program using VC++.
I use the library files (vld.h) to detect the memory leak problem.
I face memory leak problem.
Here is the sample.

char * a;

UCHAR b[100];
.
.
.

a = (char *) b;

std::string c = std::string(a);

Can anyone help me?

Thanks.

---

You dont have memory allocations done using new or malloc, so there is no leak in this code.

Thanks everyone.

I would like to show you all that the line that has been complained is
std::string c = std::string( a );

that means the last line that I posted.

Hope to hear more from you all soon....

Thanks

Quote:

---

Originally Posted by thl

Thanks everyone.

I would like to show you all that the line that has been complained is
std::string c = std::string( a );

that means the last line that I posted.

---

There is no memory leak there.

Temporarily get rid of the SQL stuff, post a complete but small program that demonstrates the problem (please, no "..." -- make sure it is a complete example), and post it. Otherwise you do not have information for anyone to tell you what is going on.

Regards.

Paul McKenzie

The program is like this,

int main(int argc, char* envp[])
{
int nRetCode = 0;
char * b;
UCHAR a[100] = "hehehe";

b = (char *) a;

string c = string(b);

return nRetCode;
}

There is no memory leak for this, but in my actual applications, after running some lines of the SQL stuffs, it claims memory leak.

Thanks

Then it could be in SQL code.

Quote:

---

Originally Posted by thl

There is no memory leak for this, but in my actual applications, after running some lines of the SQL stuffs, it claims memory leak.

---

So given this, what is your conclusion? The SQL is the thing you should be investigating.

Regards,

Paul McKenzie

It's 'heh heh' :D

What claims a memory leak? vld.h? Visual leak detector?

http://www.codeproject.com/tools/vis...select=1236065

Look, unless you know what you are doing, you will get false positives from the CRT. Can you post a complete project. Your code has no 'leak' so I'm gonna assume they call the leak check before the CRT clears.

What does it mean by call leak before CRT clear?

Thanks

You may also consider using different technology to connect to the mySql database. Consider using the ATL DB Consumer classes or ADO for db interaction. The old direct ODBC approach that you are using (SQLBindCol(hStmt, 1, SQL_C_CHAR, ....)), requires that you explicitly allocate memory for the column data. As such, you must remember to delete any allocated memory or you'll have leaks.

The ATL DB Consumer or ADO approaches take care of any memory allocation/cleanup for you and let you get on to programming other parts of your application.

Arjay, thanks a lot. There is a new way for me to move forward.

Just to confirm again, like

****************************
UCHAR ucField[50];
SDWORD sdField;

SQLBindCol(hStmt, 1, SQL_C_CHAR, ucField, sizeof(ucField), &sdField);
****************************

may cause the memory leak?

For what I have in my project, I just do as what I showed above.

Thanks