Home/ Questions/Q 9089863
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-16T22:14:36+00:00

I am a c# developer learning/relearning/brushing up on c++ I’m working on database access

  • 0

I am a c# developer learning/relearning/brushing up on c++

I’m working on database access I have the following code and im having trouble understand what the & does in this case.

SQLHENV     hEnv = NULL;

if (SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &hEnv) == SQL_ERROR)
    {

If I remove the & I get this error.

'SQLAllocHandle' : cannot convert parameter 3 from 'SQLHENV' to 'SQLHANDLE *'

at first I thought it was simply passing this field in as a reference but based on the error it reads more like it is some how allowing it to convert?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    In the context of your current example, the & operator is used to obtain the address of a variable.

    From the error message, it looks like SQLAllocHandle expects the parameter 3 to be of type SQLHANDLE * (pointer to SQLHANDLE).

    When you “removed” the &, you passed a SQLHENV to it, which could not be converted to the required type. But when you did “include” the &, it worked because I am guessing SQLHANDLE is typedefed to SQLHENV, or a SQLHENV* is convertible to SQLHANDLE* due to inheritance or other reason.

    I need to do guesswork because the signatures of SQLAllocHandle and the class relation of SQLHENV and SQLHANDLE is not mentioned in the question.

    • 0