Ambiguous symbol - cannot convert from ado::DataTypeEnum to DataTypeEnum

Question

Trying to compile a C++ project containing an SQL library and getting these errors:

error C2664: 'CNCQuickADO::ConvertADOType' : cannot convert parameter 1 from 'ado20::DataTypeEnum' to 'DataTypeEnum'
    Conversion to enumeration type requires an explicit cast
error C2664: 'CNCQuickADO::ConvertADOType' : cannot convert parameter 1 from 'ado20::DataTypeEnum' to 'DataTypeEnum'
    Conversion to enumeration type requires an explicit cast
error C2872: 'DataTypeEnum' : ambiguous symbol
    could be 'C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\dbdaoint.h : DataTypeEnum
    or 'c:\amc\source\amthrottling\release\msado15.tlh : ado20::DataTypeEnum

I use the SQL library in several other projects with no issue like this. So I am guessing it must be something to do with where I'm including the library?

Can anyone help? Thanks!

Answer 1

You may be using namespace ado20 somewhere in the code. To tell the compiler that you want to use global DataTypeEnum type (which you probably do since that is what CNCQuickADO::ConvertADOType() expects judging from error messages), declare your variable(s) with fully-qualified type ::DataTypeEnum.

Answer 2

The namespace is very important design in c++.

In ado20::DataTypeEnum, ado20 is the namespace, DataTypeEnum is the name in this namespace.

ado20::DataTypeEnum and othernamespace::DataTypeEnum are different variables which are distinguished from the namespace.

C++ realizes this by modify the variable name. For example, ado20::DataTypeEnum can be processed as _ado20_DataTypeEnum, while othernamespace::DataTypeEnum be _othernamespace_DataTypeEnum.

Another example of using the namespace:

using namespace ado20; // declare the namespace 
// other code ...
DateTypeEnum yourvariable; // now you can directly use variable in the namespace