#include dependencies management with autotools

Question

I code some C++ software and manage the whole project with the GNU autotools.

I have some part of the C++ code which is really verbose so I have made a script "generator.rb" which generate it automatically in a file "generated.cpp".

I have a build target "generated.cpp" that construct "generated.cpp" from "object_list.txt"

Up to this point everything works correctly.

Now I want to #include this "generated.cpp" file in another one "handwritten.cpp".

Since automake is said to automaticaly compute the dependencies on included files, I expect it to :

• rebuild "generated.cpp" when building "handwritten.o", if it does not exist or is not up-to-date

• trigger a new "handwritten.o" build each time object_list.txt has changed

So how can I do that ?

Remark : My source tree is like that :

./
\_src/
|  \_handwritten.cpp
|_design/
|  \_object_list.txt
\_tools/
   \_generator.rb  

Remark : My build tree is like that :

build/
 \_gcc_debug/
    |_src/
    |  \_handwritten.o
    \_design/
       \_generated.cpp

Answer 1

Since automake is said to automaticaly compute the dependencies on included files

Because Automake-generated Makefiles generate dependencies as a side effect of compilation, a file that is created as part of the build needs special treatment. You have to tell Automake to build such a file before it tries any of the normal compilations. This is done using BUILT_SOURCES, like:

BUILT_SOURCES = generated.cpp

... followed by writing the rules you need to create generated.cpp.