diff --git a/source/c2cuda.rst b/source/c2cuda.rst
index ca21551..76be356 100644
--- a/source/c2cuda.rst
+++ b/source/c2cuda.rst
@@ -715,4 +715,13 @@ This section describes the most common errors at compilation time using the pars
         some variable ----> ok
     <\EXTERNAL>
 
+* Block opening/closing not in first column::
+
+    __<EXTERNAL>
+	This block will not be parsed
+    __<\EXTERNAL>
+    <EXTERNAL>
+	This block will be parsed
+    <\EXTERNAL>
+
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