diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 1fa628109e..7d2a71c300 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -1546,8 +1546,8 @@
         <glossentry id='var-CPPFLAGS'><glossterm>CPPFLAGS</glossterm>
             <glossdef>
                 <para>
-                    Specifies the flags to pass to the C compiler and to the
-                    C pre-processor.
+                    Specifies the flags to pass to the C pre-processor
+                    (i.e. to both the C and the C++ compilers).
                     This variable is exported to an environment
                     variable and thus made visible to the software being
                     built during the compilation step.