#
# This function will prevent in-source builds
function(AssureOutOfSourceBuilds)
 # make sure the user doesn't play dirty with symlinks
 get_filename_component(srcdir "${CMAKE_SOURCE_DIR}" REALPATH)
 get_filename_component(bindir "${CMAKE_BINARY_DIR}" REALPATH)

 # disallow in-source builds
 if("${srcdir}" STREQUAL "${bindir}")
 message("######################################################")
 message("# jsoncpp should not be configured & built in the jsoncpp source directory")
 message("# You must run cmake in a build directory.")
 message("# For example:")
 message("# mkdir jsoncpp-Sandbox ; cd jsoncpp-sandbox")
 message("# git clone https://github.com/open-source-parsers/jsoncpp.git # or download & unpack the source tarball")
 message("# mkdir jsoncpp-build")
 message("# this will create the following directory structure")
 message("#")
 message("# jsoncpp-Sandbox")
 message("# +--jsoncpp")
 message("# +--jsoncpp-build")
 message("#")
 message("# Then you can proceed to configure and build")
 message("# by using the following commands")
 message("#")
 message("# cd jsoncpp-build")
 message("# cmake ../jsoncpp # or ccmake, or cmake-gui ")
 message("# make")
 message("#")
 message("# NOTE: Given that you already tried to make an in-source build")
 message("# CMake have already created several files & directories")
 message("# in your source tree. run 'git status' to find them and")
 message("# remove them by doing:")
 message("#")
 message("# cd jsoncpp-Sandbox/jsoncpp")
 message("# git clean -n -d")
 message("# git clean -f -d")
 message("# git checkout --")
 message("#")
 message("######################################################")
 message(FATAL_ERROR "Quitting configuration")
 endif()
endfunction()

AssureOutOfSourceBuilds()