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How to generate top level include file which includes all other header files from all subdirectories?

I am working on a large project with many subdirectories and many header files in those subdirectories. Subdirectories contain more subdirectories and those subdirectories have more header files. It is a big tree like multi-level structure. I want to provide top level header file to the users who doesn't want to include headers manually. Top level header file should include all other headers with relative path. I am sinking to automate the process with sed or awk, but not sure how to start.

Any tips are greatly appreciated.

Thanks.

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4 Answers 4

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4

find . -name '*.h' | sed -e 's/\.\///' -e 's/^/#include "/' -e 's/$/"/' >> master.h

  • Find all .h files
  • strip the leading "./"
  • add #include " at the beginning of line
  • add " at the end of line
  • redirect to master.h

But I'm not sure this is such a good idea.

I'd rather include only the necessary headers and keep the number of headers needed as small as possible.

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One invocation of sed can take multiple -e options (processed in order).
4

You're on the right track. Personally I'd use find and just pipe the output to a file. Something like:

 find . -name "*.h" -print > myBigHeader.h

Also, you'll want to deal with dependency generation in your makefile so that if one of those headers get's changed make will be able to recompile the objects that depend on it.

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Top level header is for convenience only. I see many project provide such a deader file.
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The other answers tell you how to do this and will work well, but there are some potential problems with this approach:

  • compile time may be significantly increased as more headers need to read in and processed.

  • a change to any header file will mean all code using your global header file would be rebuilt, even if it didn't actually use the parts that were changed.

  • makes it harder to see the project as a collection of smaller problems and sub-systems.

  • potential for function/variable name clashes and shadowing (especially in C with no namespaces to limit the scope)

A better solution is to organise your project properly. Break it down into sub-systems and libraries which have headers exposing a useful limited interface to the rest of the system, whilst keeping the implementation details internal to the library/sub-system/module.

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echo "#ifndef INCLUDEALLH" > includeall.h
echo "#define INCLUDEALLH" >> includeall.h
find . -name \*.h | sed 's,^[.]/,,' | while read line; do echo "#include \"$line\""; done >> includeall.h
echo "#endif" >> includeall.h
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