moved stream communicator creation back to SSC engine to pass windows build

source/adios2/CMakeLists.txt

@@ -162,7 +162,6 @@ endif()
 
 if(ADIOS2_HAVE_SSC)
     target_sources(adios2 PRIVATE
-        helper/adiosMpiHandshake.h  helper/adiosMpiHandshake.cpp
         engine/ssc/SscReader.cpp
         engine/ssc/SscReader.tcc
         engine/ssc/SscWriter.cpp
@@ -232,6 +231,7 @@ if(ADIOS2_HAVE_MPI)
   target_sources(adios2 PRIVATE
     core/IOMPI.cpp
     helper/adiosCommMPI.h  helper/adiosCommMPI.cpp
+    helper/adiosMpiHandshake.h  helper/adiosMpiHandshake.cpp
     engine/insitumpi/InSituMPIWriter.cpp engine/insitumpi/InSituMPIWriter.tcc
     engine/insitumpi/InSituMPIReader.cpp engine/insitumpi/InSituMPIReader.tcc
     engine/insitumpi/InSituMPIFunctions.cpp engine/insitumpi/InSituMPISchedules.cpp

source/adios2/engine/ssc/SscReader.cpp

@@ -198,7 +198,31 @@ void SscReader::SyncMpiPattern()
                              CommAsMPI(m_Comm));
 
     m_MpiAllWritersGroup = m_MpiHandshake.GetAllWritersGroup(m_Name);
-    m_StreamComm = m_MpiHandshake.GetStreamComm(m_Name);
+    std::vector<int> allStreamRanks;
+
+    for (const auto &app : m_MpiHandshake.GetWriterMap(m_Name))
+    {
+        for (int rank : app.second)
+        {
+            allStreamRanks.push_back(rank);
+        }
+    }
+
+    for (const auto &app : m_MpiHandshake.GetReaderMap(m_Name))
+    {
+        for (int rank : app.second)
+        {
+            allStreamRanks.push_back(rank);
+        }
+    }
+
+    MPI_Group worldGroup;
+    MPI_Comm_group(MPI_COMM_WORLD, &worldGroup);
+    std::sort(allStreamRanks.begin(), allStreamRanks.end());
+    MPI_Group allWorkersGroup;
+    MPI_Group_incl(worldGroup, allStreamRanks.size(), allStreamRanks.data(),
+                   &allWorkersGroup);
+    MPI_Comm_create_group(MPI_COMM_WORLD, allWorkersGroup, 0, &m_StreamComm);
 }
 
 void SscReader::SyncWritePattern()

source/adios2/engine/ssc/SscWriter.cpp

@@ -198,7 +198,31 @@ void SscWriter::SyncMpiPattern()
 
     m_MpiAllReadersGroup = m_MpiHandshake.GetAllReadersGroup(m_Name);
 
-    m_StreamComm = m_MpiHandshake.GetStreamComm(m_Name);
+    std::vector<int> allStreamRanks;
+
+    for (const auto &app : m_MpiHandshake.GetWriterMap(m_Name))
+    {
+        for (int rank : app.second)
+        {
+            allStreamRanks.push_back(rank);
+        }
+    }
+
+    for (const auto &app : m_MpiHandshake.GetReaderMap(m_Name))
+    {
+        for (int rank : app.second)
+        {
+            allStreamRanks.push_back(rank);
+        }
+    }
+
+    MPI_Group worldGroup;
+    MPI_Comm_group(MPI_COMM_WORLD, &worldGroup);
+    std::sort(allStreamRanks.begin(), allStreamRanks.end());
+    MPI_Group allWorkersGroup;
+    MPI_Group_incl(worldGroup, allStreamRanks.size(), allStreamRanks.data(),
+                   &allWorkersGroup);
+    MPI_Comm_create_group(MPI_COMM_WORLD, allWorkersGroup, 0, &m_StreamComm);
 }
 
 void SscWriter::SyncWritePattern()

source/adios2/helper/adiosMpiHandshake.cpp

@@ -254,37 +254,6 @@ MpiHandshake::GetReaderMap(const std::string &filename)
     return m_ReadersMap[filename];
 }
 
-MPI_Comm MpiHandshake::GetStreamComm(const std::string &filename)
-{
-    std::vector<int> allStreamRanks;
-
-    for (const auto &app : GetWriterMap(filename))
-    {
-        for (int rank : app.second)
-        {
-            allStreamRanks.push_back(rank);
-        }
-    }
-
-    for (const auto &app : GetReaderMap(filename))
-    {
-        for (int rank : app.second)
-        {
-            allStreamRanks.push_back(rank);
-        }
-    }
-
-    MPI_Group worldGroup;
-    MPI_Comm_group(MPI_COMM_WORLD, &worldGroup);
-    std::sort(allStreamRanks.begin(), allStreamRanks.end());
-    MPI_Group allWorkersGroup;
-    MPI_Group_incl(worldGroup, allStreamRanks.size(), allStreamRanks.data(),
-                   &allWorkersGroup);
-    MPI_Comm streamComm;
-    MPI_Comm_create_group(MPI_COMM_WORLD, allWorkersGroup, 0, &streamComm);
-    return streamComm;
-}
-
 MPI_Group MpiHandshake::GetAllReadersGroup(const std::string &filename)
 {
     std::vector<int> allReaderRanks;

source/adios2/helper/adiosMpiHandshake.h

@@ -95,16 +95,6 @@ public:
     static const std::map<int, std::vector<int>> &
     GetReaderMap(const std::string &filename);
 
-    /**
-     * Get the MPI communicator for the stream, containing all writer ranks and
-     * reader ranks that work on the stream filename
-     *
-     * @param filename: name of the staging stream
-     *
-     * @return the communicator for the stream
-     */
-    static MPI_Comm GetStreamComm(const std::string &filename);
-
     /**
      * Get the MPI group for all readers in the stream filename
      *