diff --git a/docs/pdf/penv.tex b/docs/pdf/penv.tex
index ab0136da..da5237d7 100644
--- a/docs/pdf/penv.tex
+++ b/docs/pdf/penv.tex
@@ -80,6 +80,7 @@ Specified as: an integer variable. \
 \subroutine{psb\_exit}{Exit from  PSBLAS parallel environment}
 
 \syntax{call psb\_exit}{icontxt}
+\syntax*{call psb\_exit}{icontxt,close}
 
 This subroutine exits from the  PSBLAS parallel virtual  machine.
 \begin{description}
@@ -89,13 +90,24 @@ This subroutine exits from the  PSBLAS parallel virtual  machine.
 Scope:{\bf global}.\\
 Type:{\bf required}.\\
 Specified as: an integer variable.
+\item[close] Whether to close all data structures related to the
+  virtual parallel machine, besides those associated with icontxt.\\
+Scope:{\bf global}.\\
+Type:{\bf optional}.\\
+Specified as: a logical  variable, default value: true.
 \end{description}
 
 \section*{Notes}
 \begin{enumerate}
 \item This routine may be called even if a previous call to
   \verb|psb_info| has returned with $iam=-1$; indeed, it it is the only
-  routine that may be called with argument \verb|icontxt| in this situation.
+  routine that may be called with argument \verb|icontxt| in this
+  situation.
+\item If the user wants to use multiple communication contexts in the
+  same program, this routine may be called multiple times to
+  selectively close the contexts with \verb|close=.false.|, while on
+  the last call it should be called with \verb|close=.true.| to
+  shutdown in a clean way the entire parallel environment.
 \end{enumerate}
 
 
@@ -271,6 +283,15 @@ scalar, or a rank 1 or 2 array. \\
 Type, rank and size must agree on all processes.
 \end{description}
 
+\section*{Notes}
+\begin{enumerate}
+\item The \verb|dat| argument is both input and output, and its
+  value may be changed even on processes different from the final
+  result destination.
+\end{enumerate}
+
+
+
 \subroutine{psb\_amx}{Global maximum absolute value}
 
 \syntax{call psb\_amx}{icontxt, dat, root}
@@ -308,6 +329,14 @@ scalar, or a rank 1 or 2 array. \
 Type, rank and size must agree on all processes.
 \end{description}
 
+
+\section*{Notes}
+\begin{enumerate}
+\item The \verb|dat| argument is both input and output, and its
+  value may be changed even on processes different from the final
+  result destination.
+\end{enumerate}
+
 \subroutine{psb\_amn}{Global minimum absolute value}
 
 \syntax{call psb\_amn}{icontxt, dat, root}
@@ -346,6 +375,14 @@ Type, rank and size must agree on all processes.
 \end{description}
 
 
+\section*{Notes}
+\begin{enumerate}
+\item The \verb|dat| argument is both input and output, and its
+  value may be changed even on processes different from the final
+  result destination.
+\end{enumerate}
+
+
 \subroutine{psb\_snd}{Send data}
 
 \syntax{call psb\_snd}{icontxt, dat, dst, m}
diff --git a/src/modules/psb_penv_mod.f90 b/src/modules/psb_penv_mod.f90
index 7d0c1329..8596c473 100644
--- a/src/modules/psb_penv_mod.f90
+++ b/src/modules/psb_penv_mod.f90
@@ -178,16 +178,22 @@ contains
         
   end subroutine psb_init
 
-  subroutine psb_exit(ictxt)
+  subroutine psb_exit(ictxt,close)
     integer, intent(in) :: ictxt
-    
+    logical, intent(in), optional :: close
+    logical  :: close_
     integer  :: nprow, npcol, myprow, mypcol
     
+    if (present(close)) then 
+      close_ = close
+    else
+      close_ = .true.
+    end if
     call blacs_gridinfo(ictxt, nprow, npcol, myprow, mypcol)
     if ((myprow >=0).and.(mypcol>=0)) then
       call blacs_gridexit(ictxt)
     end if
-    
+    if (close_) call blacs_exit(0)
   end subroutine psb_exit