1 files changed, 45 insertions, 0 deletions
diff --git a/include/PreventInSourceBuilds.cmake b/include/PreventInSourceBuilds.cmake
new file mode 100644
index 0000000..7ddda54
--- /dev/null
+++ b/include/PreventInSourceBuilds.cmake
@@ -0,0 +1,45 @@
+#
+# 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()