diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index de92dabb07..1bb7a5bd54 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -206,7 +206,8 @@ bool cmTarget::HasCxx() const
   for(std::vector<cmSourceFile*>::const_iterator i =  m_SourceFiles.begin();
       i != m_SourceFiles.end(); ++i)
     {
-    if((*i)->GetSourceExtension() != "c")
+    if((*i)->GetSourceExtension() != "c" &&
+       (*i)->GetSourceExtension() != "h")
       {
       return true;
       }
diff --git a/Tests/COnly/CMakeLists.txt b/Tests/COnly/CMakeLists.txt
index 1eaeb84e4f..f9a681328f 100644
--- a/Tests/COnly/CMakeLists.txt
+++ b/Tests/COnly/CMakeLists.txt
@@ -1,3 +1,3 @@
 # a simple C only test case
 PROJECT (conly C)
-ADD_EXECUTABLE (conly conly.c)
+ADD_EXECUTABLE (conly conly.c foo.c foo.h)
diff --git a/Tests/COnly/conly.c b/Tests/COnly/conly.c
index 1482f27e53..3f720ef512 100644
--- a/Tests/COnly/conly.c
+++ b/Tests/COnly/conly.c
@@ -1,4 +1,9 @@
+#include "foo.h"
+
+#include <stdio.h>
+
 int main ()
 {
+  printf("Foo: %s\n", foo);
   return 0;
 }
diff --git a/Tests/COnly/foo.c b/Tests/COnly/foo.c
new file mode 100644
index 0000000000..b42bbfd1c1
--- /dev/null
+++ b/Tests/COnly/foo.c
@@ -0,0 +1 @@
+const char* foo = "Foo";
diff --git a/Tests/COnly/foo.h b/Tests/COnly/foo.h
new file mode 100644
index 0000000000..67c42a20c5
--- /dev/null
+++ b/Tests/COnly/foo.h
@@ -0,0 +1 @@
+extern const char* foo;