#pragma warning does not work for catch statement

Question

In the following codes:

const int ME_ABORT_EXCEPTION = 1;

class CMyException
{
public:
    CMyException(int nErrorCode)
    : m_nErrorCode(nErrorCode)
    {
    }

    ~CMyException()
    {
    }

    int m_nErrorCode;   
};

void CTestExceptionDlg::OnBnClickedButton1()
{
    // TODO: Add your control notification handler code here
    try
    {
        throw CMyException(ME_ABORT_EXCEPTION);
    }
#pragma warning(disable:4101)
    catch(CMyException& e)
    {
        ASSERT(e.m_nErrorCode == ME_ABORT_EXCEPTION);
    }
#pragma warning(default:4101)
}

I try to disable the compiler warning C4101 with #pragma, but it does not work. When compiling Release version, there will still be compiler warning. Why?

The warning message is:

warning C4101: 'e' : unreferenced local variable

Answer 1

As noted in the comments, the C4101 warning works at function scope, so you have to disable it before/outside the function(s) you want to apply it to:

#pragma warning(disable:4101)
void CTestExceptionDlg::OnBnClickedButton1()
{
    // TODO: Add your control notification handler code here
    try
    {
        throw CMyException(ME_ABORT_EXCEPTION);
    }
    catch (CMyException & e)
    {
        ASSERT(e.m_nErrorCode == ME_ABORT_EXCEPTION);
    }
}
#pragma warning(default:4101)

I've tested this in VS2010 and it works. In VS2017 and VS2019, the warning is also disabled as expected in your original code arrangement.