Question

I am new to C++ from a C#.NET and Visual Studio background (and some Objective-C / XCode).

I want to write cross-platform (Windows, OS X, Linux) application with C++. I started with TextMate on my Mac and Notepad on my Windows, and compile the code using g++ on command line/terminal to build the executables on its platform.

I got confused when I started using IDE (namely VC++, XCode, and Eclipse). I tried all three and created projects before pasting my code in it. If I start editing in one IDE, I do not know how to get the eventual piece of code to compile on different platform.

For example, if I have a class file – foo.cpp. In Eclipse, it would generate foo.cpp (within it a foo.h, foo::foo()) and a separate foo.h header file (within it a FOO_H_ file etc). In Xcode, it generates a folder Foo constains main.cpp and foo.l) – that’s it. Why the difference?

I though C++ code is just C++ code which produce platform specific executables if compiled on that platform. (e.g. compile on Mac, it becomes a Mac executables; if compiled on Windows, it becomes a Windows executables).

It seems, once I started using IDE, my C++ code automatically become unportable, due to all these auto generated files that I have no understanding about. I try reading documentation on XCode, Eclipse, and Visual Studio at the same time, and it confuses me even further. I just want to write C++…

I am also following Stroustrup’s classic text to pick up C++ and in the book, nothing like header or source of .h or _H_ files were mentioned, as of why all these files were generated.

Besides using Notepad/Textmate + G++ compiler, how can I write pure, portable C++ program in an IDE that can be cross-platform, or is it even possible?

Answer 1

The default (=most commonly used) file structure for a c++ class called Foo consists of a header file called foo.h which will contain the class definition of Foo, and a foo.cpp which contains the definition of the methods of Foo.

Often all the header files are put into a seperate folder called include.

So the general approach to have the same file/folder structure, which can be used for more than one IDE is:

• create the folder structure manually (e.g. include, src and make folders inside your project folder MyProject, the project files for IDEs would go into make, .h files into include, and .cpp files into src)
• create the .h and .cpp files for your classes manually using the explorer/finder/…
• use “add existing file” or something equivalent to add those files to the project file of your IDE.
• as Rup pointed out, for Visual Studio, one should use the “empty project” preset, or it will add some header files you dont want