Eclipse CDT complains about unresolved functions but still builds successfully

Question

The following C++ application compiles and runs successfully within Eclipse CDT but the IDE is still reporting an error stating:

Answer 1

At preferences -> c/c++ -> Editor -> Indexer disable indexer, apply, go back to preferences, and enable index again. This makes Eclipse to re-index the workspace. After that, my false red signs on the right side of the editor were gone.