diff --git a/ompi/proc/proc.h b/ompi/proc/proc.h
index ffaa9e41e18..5aeeea10132 100644
--- a/ompi/proc/proc.h
+++ b/ompi/proc/proc.h
@@ -373,7 +373,7 @@ static inline bool ompi_proc_is_sentinel (ompi_proc_t *proc)
  * we assume an ompi_proc_t is at least aligned on two bytes,
  * so if the LSB of a pointer to an ompi_proc_t is 1, we have to handle
  * this pointer as a sentinel instead of a pointer.
- * a sentinel can be seen as a 64 bits array with the following format :
+ * a sentinel can be seen as an uint64_t with the following format :
  * - bit  0     : 1
  * - bits 1-15  : local jobid
  * - bits 16-31 : job family
@@ -381,9 +381,10 @@ static inline bool ompi_proc_is_sentinel (ompi_proc_t *proc)
  */
 static inline uintptr_t ompi_proc_name_to_sentinel (opal_process_name_t name)
 {
-    uintptr_t tmp, sentinel = 0x1;
+    uintptr_t tmp, sentinel = 0;
     /* local jobid must fit in 15 bits */
     assert(! (ORTE_LOCAL_JOBID(name.jobid) & 0x8000));
+    sentinel |= 0x1;
     tmp = (uintptr_t)ORTE_LOCAL_JOBID(name.jobid);
     sentinel |= ((tmp << 1) & 0xfffe);
     tmp = (uintptr_t)ORTE_JOB_FAMILY(name.jobid);
@@ -396,7 +397,7 @@ static inline uintptr_t ompi_proc_name_to_sentinel (opal_process_name_t name)
 static inline opal_process_name_t ompi_proc_sentinel_to_name (uintptr_t sentinel)
 {
   opal_process_name_t name;
-  uint16_t local, family;
+  uint32_t local, family;
   uint32_t vpid;
   assert(sentinel & 0x1);
   local = (sentinel >> 1) & 0x7fff;