Building with CMake {#build-cmake}
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[TOC]

## Quick start:

  Building and testing Log4cxx on a Unix platform with packaged APR and APR-Util.

  Make sure cmake 3.13+, g++ and make are available, install or
  build apr 1.x, apr-util 1.x, gzip and zip.

Linux example:
~~~
$ apt-get install build-essential libapr1-dev libaprutil1-dev gzip zip
$ cd apache-Log4cxx-x.x.x
$ mkdir build
$ cd build
$ ccmake ..
$ make
$ sudo make install
~~~

Windows Example:
Building and testing Log4cxx on a Microsoft Windows with APR, Expat and APR-Util built from source
extracted into apr-1.7.4, libexpat(from github) and apr-util-1.6.3 in %HOMEPATH%/Libraries.

~~~
$ cd %HOMEPATH%/Libraries
$ cmake -S libexpat/expat -B buildtrees/expat -DCMAKE_INSTALL_PREFIX=%HOMEPATH%/Libraries/installed
$ cmake --build buildtrees/expat --target install --config Release
$ cmake -S apr-1.7.4 -B buildtrees/apr -DCMAKE_INSTALL_PREFIX=%HOMEPATH%/Libraries/installed
$ cmake --build buildtrees/apr --target install --config Release
$ set CMAKE_PREFIX_PATH=%HOMEPATH%/Libraries/installed
$ cmake -S apr-util-1.6.3 -B buildtrees/apr-util -DCMAKE_INSTALL_PREFIX=%HOMEPATH%/Libraries/installed
$ cmake --build buildtrees/apr-util --target install --config Release
$ cmake -S apache-Log4cxx-x.x.x -B buildtrees/Log4cxx -DCMAKE_INSTALL_PREFIX=%HOMEPATH%/Libraries/installed
$ cmake --build buildtrees/Log4cxx --target install --config Release
~~~

## CMake options

| Option                 | Usage |
|------------------------|-------|
| -DLOG4CXX_WCHAR_T=no   | Enable wchar_t API methods, choice of yes (default), no.                                    |
| -DLOG4CXX_UNICHAR=yes  | Enable UniChar API methods, choice of yes, no (default).                                    |
| -DLOG4CXX_CFSTRING=yes | Enable CFString API methods, requires Mac OS/X CoreFoundation, choice of yes, no (default). |
| -DBUILD_TESTING=off    | Do not build tests.  Tests are built by default                                             |
| -DBUILD_SHARED_LIBS=off| Build Log4cxx as a static library. A dynamically linked Log4cxx library is built by default. Any compilation unit that includes a Log4cxx header must define LOG4CXX_STATIC.             |
| -DAPU_STATIC=yes       | Link to the APR-Util static library. By default, the Log4cxx shared library is linked to the APR-Util shared library. If BUILD_SHARED_LIBS=off, the static APR-Util library is used.     |
| -DAPR_STATIC=yes       | Link to the APR static library. By default, the Log4cxx shared library is linked to the APR shared library. If BUILD_SHARED_LIBS=off, the static APR library is always used.        |
|-DLOG4CXX_TEST_PROGRAM_PATH=path| An extra path to prepend to the PATH for test programs.  Log4cxx requires zip, sed, and grep on the PATH in order for the tests to work properly.                          |
| -DPREFER_BOOST=on      | Prefer the Boost version of dependent libraries over standard library |
| -DLOG4CXX_QT_SUPPORT=ON | Enable QString API and log4cxx::qt namespace methods, requires QtCore, choice of ON, OFF (default).                   |
| -DLOG4CXX_EVENTS_AT_EXIT=ON | Prevent static data cleanup to allow event logging during application exit. |
| -DLOG4CXX_FORMAT_NAMESPACE=std | Make the `LOG4CXX_[level]_FMT` macros use [std::format](https://en.cppreference.com/w/cpp/utility/format/format) by default.  |

# Platform specific notes:

## Mac OS/X:

APR and APR-Util are provided by the platform in Mac OS/X 10.5 and iODBC in 10.4.

cmake can be installed by typing "brew install cmake".

## Debian:

APR, APR-Util, openssl, gzip and zip may be installed by:

~~~
$ sudo apt-get install libssl-dev libapr1-dev libaprutil1-dev gzip zip
~~~

CMake can be built from source by typing:

~~~
$ wget https://github.com/Kitware/CMake/releases/download/v3.27.2/cmake-3.27.2.tar.gz
$ tar xf cmake-3.27.2.tar.gz
$ cd cmake-3.27.2
$ ./bootstrap
$ make
$ sudo make install
~~~

## FreeBSD:

APR, APR-Util, gzip and zip may be installed from the ports collection by:

~~~
$ cd /usr/ports/archivers/zip
$ make
$ make install
$ cd /usr/ports/archivers/gzip
$ make
$ make install
$ cd /usr/ports/devel/apr
$ make
$ make install
~~~

## Windows:

The easiest way to get dependencies installed is to use vcpkg(for APR/expat), and msys2 for the command-line
utilities(zip, grep, sed).

Msys2 can be downloaded from: https://www.msys2.org/
By default, this will be installed under C:\\msys2, so you can add that to the build PATH by setting
LOG4CXX_TEST_PROGRAM_PATH=C:/msys64/usr/bin in your build settings.

For vcpkg, follow the directions at https://github.com/microsoft/vcpkg#quick-start-windows and then install
the dependencies needed using `vcpkg install apr apr-util`.

# Using Log4cxx in a CMake build

A log4cxxConfig.cmake and log4cxxConfigVersion.cmake is installed to allow use of find_package()
in your CMakeLists.txt.

Below are example cmake commands that compile and link "myApplication" with Log4cxx.

~~~
find_package(log4cxx 0.11)
add_executable(myApplication myMain.cpp)
target_include_directories(myApplication PRIVATE $<TARGET_PROPERTY:log4cxx,INTERFACE_INCLUDE_DIRECTORIES>)
target_link_libraries( myApplication PRIVATE log4cxx)
~~~

