diff --git a/src_c/IMB_bandwidth.c b/src_c/IMB_bandwidth.c
index 1aa1339..f623614 100644
--- a/src_c/IMB_bandwidth.c
+++ b/src_c/IMB_bandwidth.c
@@ -104,7 +104,7 @@ Output variables:
     MPI_Status *statuses = (MPI_Status*)IMB_alloca((c_info->max_win_size) * sizeof(MPI_Status));
 
     int ws, peers;
-    char ack;
+    char ack = 0;
 
     MPI_Type_size(c_info->s_data_type, &s_size);
     MPI_Type_size(c_info->r_data_type, &r_size);
@@ -213,7 +213,7 @@ Output variables:
     MPI_Status *statuses = (MPI_Status*)IMB_alloca((2 * c_info->max_win_size) * sizeof(MPI_Status));
 
     int ws, peers;
-    char ack;
+    char ack = 0;
 
     MPI_Type_size(c_info->s_data_type, &s_size);
     MPI_Type_size(c_info->r_data_type, &r_size);
diff --git a/src_c/IMB_open_close.c b/src_c/IMB_open_close.c
index 855335c..4172ba6 100644
--- a/src_c/IMB_open_close.c
+++ b/src_c/IMB_open_close.c
@@ -105,7 +105,7 @@ Output variables:
 
 */
     double t1, t2;
-    int    i, dum;
+    int    i, dum = 0;
     MPI_Status stat;
 
     if (c_info->rank != -1) {