Features: Extend concept to C language.

Add properties and variables corresponding to CXX equivalents.

Add features for c_function_prototypes (C90), c_restrict (C99),
c_variadic_macros (C99) and c_static_assert (C11). This feature
set can be extended later.

Add a <PREFIX>_RESTRICT symbol define to WriteCompilerDetectionHeader
to conditionally represent the c_restrict feature.

6 files changed, 53 insertions, 2 deletions

diff --git a/Tests/CompileFeatures/CMakeLists.txt b/Tests/CompileFeatures/CMakeLists.txt
index adf50d5..0e1e6c9 100644
--- a/Tests/CompileFeatures/CMakeLists.txt
+++ b/Tests/CompileFeatures/CMakeLists.txt
@@ -3,7 +3,7 @@ cmake_minimum_required(VERSION 3.0)
 
 project(CompileFeatures)
 
-if (NOT CMAKE_CXX_COMPILE_FEATURES)
+if (NOT CMAKE_C_COMPILE_FEATURES AND NOT CMAKE_CXX_COMPILE_FEATURES)
   file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/dummy.cpp"
     "int main(int,char**) { return 0; }\n"
   )
@@ -22,6 +22,10 @@ macro(run_test feature lang)
   endif()
 endmacro()
 
+get_property(c_features GLOBAL PROPERTY CMAKE_C_KNOWN_FEATURES)
+foreach(feature ${c_features})
+  run_test(${feature} C)
+endforeach()
 get_property(cxx_features GLOBAL PROPERTY CMAKE_CXX_KNOWN_FEATURES)
 foreach(feature ${cxx_features})
   run_test(${feature} CXX)
@@ -34,9 +38,11 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL GNU
   )
 endif()
 
+set(C_ext c)
+set(C_standard_flag 11)
 set(CXX_ext cpp)
 set(CXX_standard_flag 11)
-foreach(lang CXX)
+foreach(lang CXX C)
   if (CMAKE_${lang}_COMPILE_FEATURES)
     foreach(feature ${${lang}_non_features})
       message("Testing feature : ${feature}")
diff --git a/Tests/CompileFeatures/c_function_prototypes.c b/Tests/CompileFeatures/c_function_prototypes.c
new file mode 100644
index 0000000..ab3c948
--- /dev/null
+++ b/Tests/CompileFeatures/c_function_prototypes.c
@@ -0,0 +1,9 @@
+
+int someFunc(int a, int b);
+
+int someFunc(int a, int b)
+{
+  (void)a;
+  (void)b;
+  return 0;
+}
diff --git a/Tests/CompileFeatures/c_restrict.c b/Tests/CompileFeatures/c_restrict.c
new file mode 100644
index 0000000..7bc7566
--- /dev/null
+++ b/Tests/CompileFeatures/c_restrict.c
@@ -0,0 +1,7 @@
+
+int f (int * restrict a, int * restrict b)
+{
+  (void)a;
+  (void)b;
+  return 0;
+}
diff --git a/Tests/CompileFeatures/c_static_assert.c b/Tests/CompileFeatures/c_static_assert.c
new file mode 100644
index 0000000..afab504
--- /dev/null
+++ b/Tests/CompileFeatures/c_static_assert.c
@@ -0,0 +1,2 @@
+
+_Static_assert(1, "Static assert test");
diff --git a/Tests/CompileFeatures/c_variadic_macros.c b/Tests/CompileFeatures/c_variadic_macros.c
new file mode 100644
index 0000000..4da111e
--- /dev/null
+++ b/Tests/CompileFeatures/c_variadic_macros.c
@@ -0,0 +1,15 @@
+
+int someFunc(int i1, char c, int i2)
+{
+  (void)i1;
+  (void)c;
+  (void)i2;
+  return 0;
+}
+
+#define FUNC_WRAPPER(...) someFunc(__VA_ARGS__)
+
+void otherFunc()
+{
+  FUNC_WRAPPER(42, 'a', 7);
+}
diff --git a/Tests/CompileFeatures/main.c b/Tests/CompileFeatures/main.c
new file mode 100644
index 0000000..831c5eb2
--- /dev/null
+++ b/Tests/CompileFeatures/main.c
@@ -0,0 +1,12 @@
+
+int foo(int * restrict a, int * restrict b)
+{
+  (void)a;
+  (void)b;
+  return 0;
+}
+
+int main()
+{
+  return 0;
+}