[[TracNav(TracNav/TOC_Development)]]
= CMake Build System =
CMake is a build tool which creates Makefile for you. There are also additional generators for any kind of development environment like KDevelop or Code::Blocks. [[br]]

== Using CMake ==
If you only want to build Makefiles for use under linux it is very simple indeed. We recommend to build 'out-of-source', which means that the Makefiles will not pollute your source directory but be put in another folder. Simple create a new one like for instance 'build', switch to it and run 'cmake ..' (.. for subsequent path).
{{{
$ mkdir build
$ cd build
$ cmake ..
}}}
With those Makefiles, the project the can be built completely:
{{{
$ make -j3
}}}
The -j3 option is to use 3 parallel tasks to boost multi core systems. The rule is to use one more task than cores on your machine.


== Rebuilding the CMakeCache ==
Sometime it happens, that CMake won't accept the new setting you added some where in a CMakeLists.txt. As a workaround -- I have not found a better solution yet -- delete the the toplevel CMakeCache, and rebuild every Makefile.
{{{
$ cd <some/branch/or/trunk> && ./cmakeclearcache && cmake . 
}}}


== Writing CMakeLists.txt ==
Just as an simple example for how to write a CMakeLists.txt.[[br]]
{{{
# Put all your source files (not headers!) in a variable to be used later
SET( MYLIB_SRC_FILES
  some_soource.cc
  another_source.cc
)

# This adds the current directory to the listing of all directories to be
# searched when looking for a header file.
INCLUDE_DIRECOTRIES(.)

# Creates the actual library. ''shared'' is dynamic under windows.
ADD_LIBRARY(mylib shared ${MYLIB_SRC_FILES})

# Link library against others. You will have to use ''${VARNAME}'' with external ones.
TARGET_LINK_LIBRARIES(mylib ${OgreMain} myOtherLib)
}}}


== Using CMake with KDevelop ==

CMake is capable of creating .kdevelop files, which are used as project files in (guess where) KDevelop. To create them simply use the following command

{{{
$ cmake .. -GKDevelop3
}}}


=== Optimize KDevelop ===
Do some configursation to make the usage of KDevelop smoother[[br]]

Go to '''{{{Project->Project Option->Build Option->Make}}}''', and do the following changes[[BR]]

 * Select Run Multiple Jobs, and set Number of Simultaneous Jobs to 3[[BR]]
 * set Make Prority to 5 [[br]]
 * Optional: Add Environment Variables [[br]]
  * i.e Name: CXXFLAGS; Value: -O2 -pipe[[br]]
  * CXXFLAGS or LDFLAGS are also possible. In fact any compiler flags can be set here[[br]]
  ''If you don't know what CFLAGS are, don't set them, otherwise use at you own discretion. Only reasonable flags will be supported''[[br]][[br]]

Go to '''{{{Project->Project Option->Run Option}}}'''
 * Working Directory: just add {{{/bin}}}
 ''you still need to run {{{./run-script}}} the first time''

== Debug CMake paths ==
If you want to look at the paths of a library, run CMake with verbose option:
{{{
$ cmake -L ..
}}}