FreeTDS Development Group

[ZIGLIO Frediano <Frediano.Ziglio AT vodafoneomnitel.it>]

> 
> Hi again,
> 
> I discovered a memory leak in the application I'm developing, 
> and I think 
> I may have traced the problem to either the Freetds ODBC driver or 
> unixODBC. Of course, it's possible I'm not explicity freeing 
> something 
> that I should.
> 
> Sample code that compiles on my RedHat 8 (x86) machine is attached 
> (change the connection parameters in main() to try it out). 
> Here's what 
> I'm doing, in pseudocode:
> 
> SQLAllocHandle(SQL_NULL_HANDLE,hEnv)
> SQLAllocHandle(hEnv,hDbc)
> SQLConnect(hDbc,...)
> Loop:
>       SQLAllocHandle(hDbc,hStmt)
>       SQLBindCol(hStmt,...)
>       SQLExecDirect(hStmt,...)
>       SQLFetch(hStmt) . . . .
>       SQLFreeStmt(hStmt)
>       SQLFreeHandle(hStmt)
> SQLDisconnect(hDbc)
> SQLFreeHandle(hDbc)
> SQLFreeHandle(hEnv)
> 
> The inner loop seems to leave 8 k unfreed ever time it is run.
> 
> To see the memory leak, run top or something alongside it and 
> watch the 
> process grow by 8 k per second.
> 
> BTW my server is SQLServer 2000, and I'm using unixODBC 2.2.2.
> 

I removed some leak today, but related to environment/connection, not
statement

Your code have some line wrong

Wrong
        SQLFreeHandle(SQL_HANDLE_STMT, &hStmt);

Correct
        SQLFreeHandle(SQL_HANDLE_STMT, hStmt);

You must pass handle, not a pointer to handle (handle are defined as void*,
so you didn't received errors... very bad odbc definition)

Also 

        erg = SQLConnect(hOdbc, ... 
        if ( erg != SQL_SUCCESS )
         ...

Should be changed to

        erg = SQLConnect(hOdbc, ... 
        if (!SQL_SUCCEEDED(erg))
         ...

(cvs driver and ms one return SQL_SUCCESS_WITH_INFO)

bye
  freddy77

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