All these manuals are only usefull for stuff that was valid with OS2.0 or earlier and/or concerns older compilers used back than.
Depending on the scope of the actual project they may even do more harm than good.
So yes, 1st thing is to learn C.
2nd thing is to really learn C *doh*
3rd one should get a grasp of gcc, make & co
After that it might be neccesary to dwefle into stuff like locale or gui-toolkit (ReAction in this case *würg*) which most likely won't be covered into deep by these manuals.
Further advices needs further info on the project.
