Merge pull request nlohmann#1330 from ax3l/topic-installEmbed

CMake: Optional Install if Embedded

CMakeLists.txt

@@ -16,6 +16,7 @@ include(ExternalProject)
 ## OPTIONS
 ##
 option(JSON_BuildTests "Build the unit tests when BUILD_TESTING is enabled." ON)
+option(JSON_Install "Install CMake targets during install step." ON)
 option(JSON_MultipleHeaders "Use non-amalgamated version of the library." OFF)
 
 ##
@@ -96,32 +97,34 @@ configure_file(
     @ONLY
 )
 
-install(
-    DIRECTORY ${NLOHMANN_JSON_INCLUDE_BUILD_DIR}
-    DESTINATION ${NLOHMANN_JSON_INCLUDE_INSTALL_DIR}
-)
-install(
-    FILES ${NLOHMANN_JSON_CMAKE_PROJECT_CONFIG_FILE} ${NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE}
-    DESTINATION ${NLOHMANN_JSON_CONFIG_INSTALL_DIR}
-)
-if (NLOHMANN_ADD_NATVIS)
+if(JSON_Install)
     install(
-        FILES ${NLOHMANN_NATVIS_FILE}
-        DESTINATION .
-)
+        DIRECTORY ${NLOHMANN_JSON_INCLUDE_BUILD_DIR}
+        DESTINATION ${NLOHMANN_JSON_INCLUDE_INSTALL_DIR}
+    )
+    install(
+        FILES ${NLOHMANN_JSON_CMAKE_PROJECT_CONFIG_FILE} ${NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE}
+        DESTINATION ${NLOHMANN_JSON_CONFIG_INSTALL_DIR}
+    )
+    if (NLOHMANN_ADD_NATVIS)
+        install(
+            FILES ${NLOHMANN_NATVIS_FILE}
+            DESTINATION .
+    )
+    endif()
+    export(
+        TARGETS ${NLOHMANN_JSON_TARGET_NAME}
+        NAMESPACE ${PROJECT_NAME}::
+        FILE ${NLOHMANN_JSON_CMAKE_PROJECT_TARGETS_FILE}
+    )
+    install(
+        TARGETS ${NLOHMANN_JSON_TARGET_NAME}
+        EXPORT ${NLOHMANN_JSON_TARGETS_EXPORT_NAME}
+        INCLUDES DESTINATION ${NLOHMANN_JSON_INCLUDE_INSTALL_DIR}
+    )
+    install(
+        EXPORT ${NLOHMANN_JSON_TARGETS_EXPORT_NAME}
+        NAMESPACE ${PROJECT_NAME}::
+        DESTINATION ${NLOHMANN_JSON_CONFIG_INSTALL_DIR}
+    )
 endif()
-export(
-    TARGETS ${NLOHMANN_JSON_TARGET_NAME}
-    NAMESPACE ${PROJECT_NAME}::
-    FILE ${NLOHMANN_JSON_CMAKE_PROJECT_TARGETS_FILE}
-)
-install(
-    TARGETS ${NLOHMANN_JSON_TARGET_NAME}
-    EXPORT ${NLOHMANN_JSON_TARGETS_EXPORT_NAME}
-    INCLUDES DESTINATION ${NLOHMANN_JSON_INCLUDE_INSTALL_DIR}
-)
-install(
-    EXPORT ${NLOHMANN_JSON_TARGETS_EXPORT_NAME}
-    NAMESPACE ${PROJECT_NAME}::
-    DESTINATION ${NLOHMANN_JSON_CONFIG_INSTALL_DIR}
-)

README.md

@@ -100,6 +100,10 @@ To embed the library directly into an existing CMake project, place the entire s
 # run from your own project's code.
 set(JSON_BuildTests OFF CACHE INTERNAL "")
 
+# If you only include this third party in PRIVATE source files, you do not
+# need to install it when your main project gets installed.
+# set(JSON_Install OFF CACHE INTERNAL "")
+
 # Don't use include(nlohmann_json/CMakeLists.txt) since that carries with it
 # unintended consequences that will break the build.  It's generally
 # discouraged (although not necessarily well documented as such) to use