diff --git a/reference/exec/functions/proc-close.xml b/reference/exec/functions/proc-close.xml
index b61cfba3ea..6dcee79c69 100644
--- a/reference/exec/functions/proc-close.xml
+++ b/reference/exec/functions/proc-close.xml
@@ -45,10 +45,24 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
   <para>
-   Returns the termination status of the process that was run.
+   Returns the termination status of the process that was run. In case of 
+   an error then <literal>-1</literal> is returned.
   </para>
  </refsect1>
 
+ <refsect1 role="notes">
+  &reftitle.notes;
+  <note>
+   <title>Unix Only:</title>
+   <para>
+    <function>proc_close</function> is internally implemented using the 
+    <literal>waitpid(3)</literal> system call. To obtain the real exit 
+    status code the <function>pcntl_wexitstatus</function> function 
+    should be used.
+   </para>
+  </note>
+ </refsect1>
+
 </refentry>
 
 <!-- Keep this comment at the end of the file
diff --git a/reference/filesystem/functions/pclose.xml b/reference/filesystem/functions/pclose.xml
index 3cb185f66f..0f597e802e 100644
--- a/reference/filesystem/functions/pclose.xml
+++ b/reference/filesystem/functions/pclose.xml
@@ -37,7 +37,8 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
   <para>
-   Returns the termination status of the process that was run.
+   Returns the termination status of the process that was run. In case of 
+   an error then <literal>-1</literal> is returned.
   </para>
  </refsect1>
 
@@ -58,6 +59,19 @@ pclose($handle);
   </para>
  </refsect1>
 
+ <refsect1 role="notes">
+  &reftitle.notes;
+  <note>
+   <title>Unix Only:</title>
+   <para>
+    <function>proc_close</function> is internally implemented using the 
+    <literal>waitpid(3)</literal> system call. To obtain the real exit 
+    status code the <function>pcntl_wexitstatus</function> function 
+    should be used.
+   </para>
+  </note>
+ </refsect1>
+
  <refsect1 role="seealso">
   &reftitle.seealso;
   <para>