define external counter function SQLDriverConnect
     (  read-only SQL_handle_type ConnectionHandle,
        read-only SQL_handle_type WindowHandle,
        value stream InConnectionString,
        value counter StringLength1,
        modifiable stream OutConnectionString,
        value counter BufferLength,
        modifiable counter StringLength2,
        value counter DriverCompletion )

An alternative to SQLConnect, it supports the following:

• data sources that require more connection information than the three arguments in SQLConnect.
• dialog boxes to prompt the user for all connection information.
• data sources that aren't defined in the system information.

Input arguments:

1. ConnectionHandle.
2. WindowHandle. The application can pass the handle of the parent window, if applicable, or a null pointer if either the window handle is not applicable or SQLDriverConnect will not present any dialog boxes.
3. InConnectionString. A full connection string, a partial connection string, or an empty string.
4. StringLength1. The length of InConnectionString.
5. BufferLength. The maximum length of OutConnectionString.
6. DriverCompletion. A flag that indicates whether the Driver Manager of the driver must prompt for more connection information. The following values are allowed:
   • SQL_DRIVER_NOPROMPT
   • SQL_DRIVER_COMPLETE
   • SQL_DRIVER_PROMPT
   • SQL_DRIVER_COMPLETE_REQUIRED

Output arguments:

• OutConnectionString. Upon successful connection to the target data source, this buffer contains the completed connection string.
• StringLength2. The returned length of OutConnectionString.