Here's an excerpt from my answer to another question.
Unresolved Identifier
If the source of the .cpp file looks like this
Click with the right mouse button on your project.
Check C/C++ Code As...
Run Reparse Project.
If that is not enough.
Go to Project Properties
Fill in the Include input field as described.
Set the include path correct.
I hope that can help you.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
