Merge pull request open-source-parsers#387 from joerg-krause/cmake-option-strict-iso

Disable -pedantic conditionally; add -pedantic-errors and -Werror conditionally

Author: cdunn2001

CMakeLists.txt

@@ -7,6 +7,7 @@ ENABLE_TESTING()
 OPTION(JSONCPP_WITH_TESTS "Compile and (for jsoncpp_check) run JsonCpp test executables" ON)
 OPTION(JSONCPP_WITH_POST_BUILD_UNITTEST "Automatically run unit-tests as a post build step" ON)
 OPTION(JSONCPP_WITH_WARNING_AS_ERROR "Force compilation to fail if a warning occurs" OFF)
+OPTION(JSONCPP_WITH_STRICT_ISO "Issue all the warnings demanded by strict ISO C and ISO C++" ON)
 OPTION(JSONCPP_WITH_PKGCONFIG_SUPPORT "Generate and install .pc files" ON)
 OPTION(JSONCPP_WITH_CMAKE_PACKAGE "Generate and install cmake package files" OFF)
 OPTION(BUILD_SHARED_LIBS "Build jsoncpp_lib as a shared library." OFF)
@@ -83,6 +84,11 @@ macro(UseCompilationWarningAsError)
         # Only enabled in debug because some old versions of VS STL generate
         # warnings when compiled in release configuration.
 		set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /WX ")
+  elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
+    if (JSONCPP_WITH_STRICT_ISO)
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic-errors")
+    endif ()
 	endif()
 endmacro()
 
@@ -100,8 +106,12 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Wconversion -Wshadow -Wno-sign-conversion")
 elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   # using GCC
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Wconversion -Wshadow -Wextra -pedantic")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Wconversion -Wshadow -Wextra")
   # not yet ready for -Wsign-conversion
+
+  if (JSONCPP_WITH_STRICT_ISO AND NOT JSONCPP_WITH_WARNING_AS_ERROR)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic")
+  endif ()
 endif()
 
 find_program(CCACHE_FOUND ccache)