From 1b27ce1ea2227e170aab8c2ec3c94745bb9b882f Mon Sep 17 00:00:00 2001
From: Martin Kronbichler <kronbichler@lnm.mw.tum.de>
Date: Thu, 20 Nov 2014 15:47:24 +0100
Subject: [PATCH] Third attempt to fix uninitialized variable in MPI::MinMaxAvg

---
 include/deal.II/base/mpi.h |  4 ++--
 source/base/mpi.cc         | 18 +++++-------------
 2 files changed, 7 insertions(+), 15 deletions(-)

diff --git a/include/deal.II/base/mpi.h b/include/deal.II/base/mpi.h
index 75a5667f2f..da8b667f4d 100644
--- a/include/deal.II/base/mpi.h
+++ b/include/deal.II/base/mpi.h
@@ -216,8 +216,8 @@ namespace Utilities
      */
     struct MinMaxAvg
     {
-      MinMaxAvg();
-
+      // Note: We assume a POD property of this struct in the MPI calls in
+      // min_max_avg
       double sum;
       double min;
       double max;
diff --git a/source/base/mpi.cc b/source/base/mpi.cc
index 3fc0077a91..c1bce6890e 100644
--- a/source/base/mpi.cc
+++ b/source/base/mpi.cc
@@ -230,7 +230,11 @@ namespace Utilities
     min_max_avg(const double my_value,
                 const MPI_Comm &mpi_communicator)
     {
-      MinMaxAvg result;
+      // To avoid uninitialized values on some MPI implementations, provide
+      // result with a default value already...
+      MinMaxAvg result = { 0., std::numeric_limits<double>::max(),
+                           -std::numeric_limits<double>::max(), 0, 0, 0.
+                         };
 
       const unsigned int my_id
         = dealii::Utilities::MPI::this_mpi_process(mpi_communicator);
@@ -310,18 +314,6 @@ namespace Utilities
 
 
 
-    MinMaxAvg::MinMaxAvg ()
-      :
-      sum (0.),
-      min (std::numeric_limits<double>::max()),
-      max (-min),
-      min_index (0),
-      max_index (0),
-      avg (0)
-    {}
-
-
-
     MPI_InitFinalize::MPI_InitFinalize (int    &argc,
                                         char ** &argv,
                                         const unsigned int max_num_threads)
-- 
2.39.5