CheckStructHasMember: Add support for C++

Previously if headers required to check if a struct has a member can be
compiled with C++ compiler only, the check would fail because the C
compiler fails.  As a consequence, the result variable would be set to
false, even if the struct has that particular member.

Teach CHECK_STRUCT_HAS_MEMBER to accept a new optional argument LANGUAGE
that allows one to explicitly set the compiler to use.  The new
signature is therefore:

  CHECK_STRUCT_HAS_MEMBER (<struct> <member> <header> <variable>
                           [LANGUAGE <language>])

4 files changed, 120 insertions, 0 deletions

diff --git a/Tests/CMakeOnly/CMakeLists.txt b/Tests/CMakeOnly/CMakeLists.txt
index be7ddbc..7586de6 100644
--- a/Tests/CMakeOnly/CMakeLists.txt
+++ b/Tests/CMakeOnly/CMakeLists.txt
@@ -19,6 +19,8 @@ add_CMakeOnly_test(CheckCXXCompilerFlag)
 
 add_CMakeOnly_test(CheckLanguage)
 
+add_CMakeOnly_test(CheckStructHasMember)
+
 add_CMakeOnly_test(CompilerIdC)
 add_CMakeOnly_test(CompilerIdCXX)
 if(CMAKE_Fortran_COMPILER)
diff --git a/Tests/CMakeOnly/CheckStructHasMember/CMakeLists.txt b/Tests/CMakeOnly/CheckStructHasMember/CMakeLists.txt
new file mode 100644
index 0000000..f06d5c3
--- /dev/null
+++ b/Tests/CMakeOnly/CheckStructHasMember/CMakeLists.txt
@@ -0,0 +1,93 @@
+cmake_minimum_required(VERSION 2.8)
+
+project(CheckStructHasMember)
+
+set(CMAKE_REQUIRED_INCLUDES "${CMAKE_CURRENT_SOURCE_DIR}")
+
+include(CheckStructHasMember)
+
+foreach(_config_type Release RelWithDebInfo MinSizeRel Debug)
+    set(CMAKE_TRY_COMPILE_CONFIGURATION ${_config_type})
+    unset(CSHM_RESULT_S1_${_config_type} CACHE)
+    unset(CSHM_RESULT_S2_${_config_type} CACHE)
+    unset(CSHM_RESULT_S3_${_config_type} CACHE)
+    message(STATUS "Testing configuration ${_config_type}")
+
+    check_struct_has_member("struct non_existent_struct" "foo" "cm_cshm.h" CSHM_RESULT_S1_${_config_type})
+    check_struct_has_member("struct struct_with_member" "non_existent_member" "cm_cshm.h" CSHM_RESULT_S2_${_config_type})
+    check_struct_has_member("struct struct_with_member" "member" "cm_cshm.h" CSHM_RESULT_S3_${_config_type})
+
+    if(CSHM_RESULT_S1_${_config_type} OR CSHM_RESULT_S2_${_config_type})
+        message(SEND_ERROR "CheckStructHasMember reported a nonexistent member as existing in configuration ${_config_type}")
+    endif()
+
+    if(NOT CSHM_RESULT_S3_${_config_type})
+        message(SEND_ERROR "CheckStructHasMember did not report an existent member as existing in configuration ${_config_type}")
+    endif()
+endforeach()
+
+foreach(_config_type Release RelWithDebInfo MinSizeRel Debug)
+    set(CMAKE_TRY_COMPILE_CONFIGURATION ${_config_type})
+    unset(CSHM_RESULT_S1_${_config_type}_C CACHE)
+    unset(CSHM_RESULT_S2_${_config_type}_C CACHE)
+    unset(CSHM_RESULT_S3_${_config_type}_C CACHE)
+    message(STATUS "Testing configuration ${_config_type}")
+
+    check_struct_has_member("struct non_existent_struct" "foo" "cm_cshm.h" CSHM_RESULT_S1_${_config_type}_C LANGUAGE C)
+    check_struct_has_member("struct struct_with_member" "non_existent_member" "cm_cshm.h" CSHM_RESULT_S2_${_config_type}_C LANGUAGE C)
+    check_struct_has_member("struct struct_with_member" "member" "cm_cshm.h" CSHM_RESULT_S3_${_config_type}_C LANGUAGE C)
+
+    if(CSHM_RESULT_S1_${_config_type}_C OR CSHM_RESULT_S2_${_config_type}_C)
+        message(SEND_ERROR "CheckStructHasMember reported a nonexistent member as existing in configuration ${_config_type}")
+    endif()
+
+    if(NOT CSHM_RESULT_S3_${_config_type}_C)
+        message(SEND_ERROR "CheckStructHasMember did not report an existent member as existing in configuration ${_config_type}")
+    endif()
+endforeach()
+
+foreach(_config_type Release RelWithDebInfo MinSizeRel Debug)
+    set(CMAKE_TRY_COMPILE_CONFIGURATION ${_config_type})
+    unset(CSHM_RESULT_S1_${_config_type}_CXX CACHE)
+    unset(CSHM_RESULT_S2_${_config_type}_CXX CACHE)
+    unset(CSHM_RESULT_S3_${_config_type}_CXX CACHE)
+    unset(CSHM_RESULT_C1_${_config_type}_CXX CACHE)
+    unset(CSHM_RESULT_C2_${_config_type}_CXX CACHE)
+    unset(CSHM_RESULT_C3_${_config_type}_CXX CACHE)
+
+    message(STATUS "Testing configuration ${_config_type}")
+
+    check_struct_has_member("non_existent_struct" "foo" "cm_cshm.h" CSHM_RESULT_S1_${_config_type}_CXX LANGUAGE CXX)
+    check_struct_has_member("struct_with_non_existent_members" "non_existent_member" "cm_cshm.h" CSHM_RESULT_S2_${_config_type}_CXX LANGUAGE CXX)
+    check_struct_has_member("struct struct_with_member" "member" "cm_cshm.h" CSHM_RESULT_S3_${_config_type}_CXX LANGUAGE CXX)
+    check_struct_has_member("ns::non_existent_class" "foo" "cm_cshm.hxx" CSHM_RESULT_C1_${_config_type}_CXX LANGUAGE CXX)
+    check_struct_has_member("ns::class_with_non_existent_members" "foo" "cm_cshm.hxx" CSHM_RESULT_C2_${_config_type}_CXX LANGUAGE CXX)
+    check_struct_has_member("ns::class_with_member" "foo" "cm_cshm.hxx" CSHM_RESULT_C3_${_config_type}_CXX LANGUAGE CXX)
+
+    if(CSHM_RESULT_S1_${_config_type}_CXX OR CSHM_RESULT_S2_${_config_type}_CXX OR CSHM_RESULT_C1_${_config_type}_CXX OR CSHM_RESULT_C2_${_config_type}_CXX)
+        message(SEND_ERROR "CheckStructHasMember reported a nonexistent member as existing in configuration ${_config_type}")
+    endif()
+
+    if(NOT CSHM_RESULT_S3_${_config_type}_CXX OR NOT CSHM_RESULT_C3_${_config_type}_CXX)
+        message(SEND_ERROR "CheckStructHasMember did not report an existent member as existing in configuration ${_config_type}")
+    endif()
+endforeach()
+
+
+set(CMAKE_TRY_COMPILE_CONFIGURATION ${CMAKE_BUILD_TYPE})
+
+if (CMAKE_COMPILER_IS_GNUCC)
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O3")
+    unset(CSHM_RESULT_O3 CACHE)
+    unset(CSHM_RESULT_O3_C CACHE)
+    unset(CSHM_RESULT_O3_CXX CACHE)
+    message(STATUS "Testing with optimization -O3")
+
+    check_struct_has_member("class_with_non_existent_members" foo "cm_cshm.h" CSHM_RESULT_O3)
+    check_struct_has_member("class_with_non_existent_members" foo "cm_cshm.h" CSHM_RESULT_O3_C LANGUAGE C)
+    check_struct_has_member("class_with_non_existent_members" foo "cm_cshm.h" CSHM_RESULT_O3_CXX LANGUAGE CXX)
+
+  if (CSE_RESULT_O3 OR CSHM_RESULT_O3_C OR CSHM_RESULT_O3_CXX)
+    message(SEND_ERROR "CheckSymbolExists reported a nonexistent symbol as existing with optimization -O3")
+  endif ()
+endif ()
diff --git a/Tests/CMakeOnly/CheckStructHasMember/cm_cshm.h b/Tests/CMakeOnly/CheckStructHasMember/cm_cshm.h
new file mode 100644
index 0000000..82bb049
--- /dev/null
+++ b/Tests/CMakeOnly/CheckStructHasMember/cm_cshm.h
@@ -0,0 +1,9 @@
+#ifndef _CSHM_DUMMY_H
+#define _CSHM_DUMMY_H
+
+struct non_existent_struct;
+struct struct_with_member{
+    int member;
+};
+
+#endif
diff --git a/Tests/CMakeOnly/CheckStructHasMember/cm_cshm.hxx b/Tests/CMakeOnly/CheckStructHasMember/cm_cshm.hxx
new file mode 100644
index 0000000..458a99b
--- /dev/null
+++ b/Tests/CMakeOnly/CheckStructHasMember/cm_cshm.hxx
@@ -0,0 +1,16 @@
+#ifndef _CSHM_DUMMY_HXX
+#define _CSHM_DUMMY_HXX
+
+namespace ns {
+
+class non_existent_class;
+class class_with_non_existent_members {
+};
+class class_with_member {
+public:
+    int foo;
+};
+
+}
+
+#endif