Are there any tools that help organizing the #includes that belong at the top of a .c or .h file?
I was just wondering because I am reorganizing my code, moving various small function definitions/declarations from one long file into different smaller files. Now each of the smaller files needs a subset of the #includes that were at the top of the long file.
It's just annoying and error-prone to figure out all #includes by hand. Often the code compiles even though not all #includes are there. Example: File A uses std::vector extensively but doesn't include vector; but it currently includes some obscure other header which happens to include vector (maybe through some recursive includes).
VisualAssistX can help you jumping to the definition of a type. E.g. if you use a class MyClass in your source, you can click it, choose goto definition, and VisualAssistX opens the include file that contains the definition of this class (possibly Visual Studio can also do this, but at this point am so getting used to VisualAssistX, that I contribute every wonderful feature to VisualAssistX :-)). You can use this to find the include file necessary for your source code.
PC-Lint can do exactly the opposite. If you have an include file in your source that is not being used, PC-Lint can warn you about it, so that you know that the include file can be removed from the source (which will have a positive impact on your compilation time).
makedepend and gccmakedep
I have been dealing with this problem lately. In our project we use C++ and have one X.h and one X.cpp file for each class X.
My strategy is the following:
(1) If A.h, where class A is declared, refers to a class B, then I have to include header B.h. If the declaration of class A contains only the type *B, then I only need a forward declaration class B; in A.h. I might need to include B.h in A.cpp
(2) Using the above procedure, I move as many includes as possible from A.h to A.cpp. Then I try removing one include at a time and see if the .cpp file still compiles. This should allow to minimize the set of included files in the .cpp file, but I am not 100% sure if the result is minimal. I also think one can write a tool to do this automatically. I had started to write one for Visual Studio. I would be glad to know that there are such tools.
Note: maybe adding a proper module construct with well-defined import / export relations could be a desired addition for C++0x. It would make the task of reorganizing imports much easier and speed up compilation a lot.
Since this question has been asked a new tool has been created: include-what-you-use, it is based on clang, provides mappings to fake the existence of certain symbols (unique_ptr in memory, but actually defined in bits/unique_ptr.h in some standard headers and lets you provide your own mappings.
It provides nice diagnostics and automatic rewriting.
Now each of the smaller files needs a subset of the #includes that were at the top of the long file.
I do this using VisualAssistX. Firstly compile the file to see what is missing. Then you can use VisualAssistX's Add include function. So I just go and right-click on the functions or classes that I know need an include and hit Add Include. Recompile a couple of times to filter out new missing includes and it is done. I hope I wrote that understandably :)
Not perfect, but faster than doing it by hand.
I use the doxygen/dot-graphviz generated graphs to see how files are linked. Very handy, but not automatic, you have to visually check the graphs, then edit you code to remove unnecessary "#include" lines. Of course, not really suited for very-large projects (say > 100 files), where the graphs become unusable.
来源：https://stackoverflow.com/questions/3644293/are-there-tools-that-help-organizing-includes