[CMake] compiling implementation first in dependancies

[Mathieu Malaterre]

On 6/15/07, Philippe Fremy <phil at freehackers.org> wrote:
> Filip Brcic wrote:
> > Дана четвртак 14 јун 2007, Philippe Fremy је написао(ла):
> >>      Hi,
> >>
> >> In my project, I have very often a pattern like this:
> >> a.cpp:
> >> #include "z.h"
> >>
> >> b.cpp:
> >> #include "z.h"
> >>
> >> c.cpp:
> >> #include "z.h"
> >>
> >>
> >> z.cpp:
> >> #include "z.h"
> >>
> >>
> >> If I change z.h and z.cpp to add a new method, I usually don't get z.h
> >> to work out of the box, but only realize it when compiling z.cpp .
> >> What's annoying is that cmake will first compile a.cpp , b.cpp , c.cpp
> >> and then only z.cpp .
> >>
> >> It there any way to tell CMake "compile the cpp file whose name match
> >> the header file first" ?
> >>
> > [100%] Built target cmakeOrderTest
> >
> > Well, I decided to play a bit and changed the order of files in the
> > CMakeLists.txt. The first set was {a.cpp b.cpp ... z.cpp} and after I moved
> > z.cpp to the beginning of the list, I got the following output (after
> > repeating the whole procedure again, of course):
> >
> > brcha at brcha ~/tmp/cmakeOrderTest/build-disordered $ make
> > Scanning dependencies of target cmakeOrderTest
> > [ 20%] Building CXX object CMakeFiles/cmakeOrderTest.dir/z.o
> > [ 40%] Building CXX object CMakeFiles/cmakeOrderTest.dir/a.o
> > [ 60%] Building CXX object CMakeFiles/cmakeOrderTest.dir/b.o
> > [ 80%] Building CXX object CMakeFiles/cmakeOrderTest.dir/c.o
> > [100%] Building CXX object CMakeFiles/cmakeOrderTest.dir/main.o
> > Linking CXX executable cmakeOrderTest
> > [100%] Built target cmakeOrderTest
> >
> > I guess that is what you wanted to achieve.
>
> That's true, but I need a more generic solution. I have about 30 files
> in my current project and depending on which one I am working on, I need
> a different order. Changing the CMakelist order is not a viable long
> term solution.
>
> Choosing the target the way Alexander pointed out is the right solution.

The other trick you might not know, is the '/fast'. Let say you have a
target foo. To build the target foo, without traversing the dependency
tree, simply type:

 make foo/fast

2 cents,
-Mathieu