diff --git a/ompi/mpi/c/testall.c b/ompi/mpi/c/testall.c
index 9155ac6d5b..ba2c843492 100644
--- a/ompi/mpi/c/testall.c
+++ b/ompi/mpi/c/testall.c
@@ -67,6 +67,7 @@ int MPI_Testall(int count, MPI_Request requests[], int *flag,
     }
 
     if (OPAL_UNLIKELY(0 == count)) {
+        *flag = true;
         return MPI_SUCCESS;
     }
 
diff --git a/ompi/mpi/c/testany.c b/ompi/mpi/c/testany.c
index 21e09752da..c2f2a50828 100644
--- a/ompi/mpi/c/testany.c
+++ b/ompi/mpi/c/testany.c
@@ -67,6 +67,8 @@ int MPI_Testany(int count, MPI_Request requests[], int *indx, int *completed, MP
     }
 
     if (OPAL_UNLIKELY(0 == count)) {
+        *completed = true;
+        *indx = MPI_UNDEFINED;
         return MPI_SUCCESS;
     }
 
diff --git a/ompi/mpi/c/testsome.c b/ompi/mpi/c/testsome.c
index 4033e2ac7f..3f58d7853c 100644
--- a/ompi/mpi/c/testsome.c
+++ b/ompi/mpi/c/testsome.c
@@ -69,6 +69,7 @@ int MPI_Testsome(int incount, MPI_Request *requests,
     }
 
     if (OPAL_UNLIKELY(0 == incount)) {
+        *outcount = MPI_UNDEFINED;
         return OMPI_SUCCESS;
     }
 
diff --git a/ompi/mpi/c/waitany.c b/ompi/mpi/c/waitany.c
index e2c0c4ed8a..895575d3aa 100644
--- a/ompi/mpi/c/waitany.c
+++ b/ompi/mpi/c/waitany.c
@@ -67,6 +67,7 @@ int MPI_Waitany(int count, MPI_Request *requests, int *indx, MPI_Status *status)
     }
 
     if (OPAL_UNLIKELY(0 == count)) {
+        *indx = MPI_UNDEFINED;
         return MPI_SUCCESS;
     }
 
diff --git a/ompi/mpi/c/waitsome.c b/ompi/mpi/c/waitsome.c
index 3fc8bf8df3..bcddcb1530 100644
--- a/ompi/mpi/c/waitsome.c
+++ b/ompi/mpi/c/waitsome.c
@@ -69,6 +69,7 @@ int MPI_Waitsome(int incount, MPI_Request *requests,
     }
 
     if (OPAL_UNLIKELY(0 == incount)) {
+        *outcount = MPI_UNDEFINED;
         return MPI_SUCCESS;
     }