Warning C33001

VARIANT 'var' was cleared when it was uninitialized (expression 'expr')

Remarks

This warning is triggered when an uninitialized VARIANT is passed to an API, such as VariantClear, that clears the object. Initialize the VARIANT before passing it to these functions so it can be properly cleared.

This warning applies to these functions:

• VariantClear
• PropVariantClear
• VariantCopy
• VariantCopyInd
• VariantChangeType
• VariantChangeTypeEx
• DestroyPropVariant

Code analysis name: VARIANTCLEAR_UNINITIALIZED

Example

The following code causes warning C33001:

#include <Windows.h>

HRESULT foo(bool some_condition)
{
    VARIANT var;

    if (some_condition)
    {
        //...
        VariantInit(&var);
        //...
    }

    VariantClear(&var);  // C33001
}

In this example, the warning is corrected by calling VariantClear only after var has been initialized:

#include <Windows.h>

HRESULT foo(bool some_condition)
{
    VARIANT var;

    if (some_condition)
    {
        //...
        VariantInit(&var);
        //...
        VariantClear(&var);  // OK
    }
}

See also

C33004
C33005