Qmake project dependencies (linked libraries)

Question

I have a project that links to a number of shared libraries.

Lets say project A depends on projects B and C

Ideally, I want to impose the following dependencies in my project file:

1. Rebuild project A if either B or C has been rebuilt since last time project A was built
2. Use the output for the relevant configuration (i.e. if building project A in debug mode, then use the debug versions of the libs for project B and C)

Does anyone know how I may explicitly express such dependencies in my project file?

Answer 1

After quite a bit of frustration with qmake, I have found what I think is the answer to your question. If not, then I have learned the way that I will use qmake until I find something better, because this is still a little bit ugly. I set up a demo project, this is my directory structure (files have extensions, folders do not):

MyProj     MyProj.pro     myproj-core         myproj-core.pro         globals.h         MyProjCore.h         MyProjCore.cpp     myproj-app         myproj-app.pro         main.cpp 

We start with MyProj.pro as a subdirs project, which is the key to doing what you ask. Basically, instead of depending on other projects to specify debug/release and all sorts of other junk, you just set it on the one qmake file. It doesn't let you make only what you need, but it's the best solution I could come up with. Here are the contents:

TEMPLATE = subdirs # Needed to ensure that things are built right, which you have to do yourself :( CONFIG += ordered  # All the projects in your application are sub-projects of your solution SUBDIRS = myproj-core \           myproj-app  # Use .depends to specify that a project depends on another. myproj-app.depends = myproj-core 

myproj-core.pro is your typical shared object library:

QT -= gui TARGET = myproj-core TEMPLATE = lib DEFINES += MYPROJCORE_LIBRARY SOURCES += MyProjCore.cpp HEADERS += MyProjCore.h \            globals.h 

myproj-app.pro is consumer application, where the little rebuild-when-needed trick is:

QT       -= gui  TARGET = myproj-app CONFIG   += console CONFIG   -= app_bundle  TEMPLATE = app  # Specify that we're lookin in myproj-core.  Realistically, this should be put # in some configuration file INCLUDEPATH += ../myproj-core # Link to the library generated by the project.  Could use variables or # something here to make it more bulletproof LIBS += ../myproj-core/libmyproj-core.so # Specify that we depend on the library (which, logically would be implicit from # the fact that we are linking to it) PRE_TARGETDEPS += ../myproj-core/libmyproj-core.so  SOURCES += main.cpp 

I hope this solves your problem, as I know it solved mine!

EDIT: I made a file specifically for building the dependencies for me, I store it in a sibling folder of each of my projects (child of the MyProj in the directory structure specified above) called dependencies.pri:

# On windows, a shared object is a .dll win32: SONAME=dll else:  SONAME=so  # This function sets up the dependencies for libraries that are built with # this project.  Specify the libraries you need to depend on in the variable # DEPENDENCY_LIBRARIES and this will add for(dep, DEPENDENCY_LIBRARIES) {     #message($$TARGET depends on $$dep ($${DESTDIR}/$${dep}.$${SONAME}))     LIBS += $${DESTDIR}/lib$${dep}.$${SONAME}     PRE_TARGETDEPS += $${DESTDIR}/lib$${dep}.$${SONAME} } 

So at the bottom of all the consuming applications, I can add the lines:

DEPENDENCY_LIBRARIES = myproj-core  include(../config/dependencies.pri) 

This assumes that you are copying the libraries to some shared location and/or moving them around as needed, so my function might not work for you, but I figured I would add it to the solution.

Answer 2

I use the solution below. This works without the usage of an extra .pro file with subdir template.

TEMPLATE = app TARGET = MyApp PRE_TARGETDEPS = ../../libs/MyLib/MyLib.a INCLUDEPATH += ../../libs/MyLib/include  HEADERS += src/MyApp.h \     ../../libs/MyLib/incude/MyLib.h SOURCES += src/MyApp.cpp LIBS += ../../libs/MyLib/MyLib.a  MyLib.target = ../../libs/MyLib/MyLib.a MyLib.commands = cd ../../libs/MyLib && make MyLib.depends = ../../libs/MyLib/Makefile QMAKE_EXTRA_TARGETS += MyLib