diff --git a/nsprpub/pr/src/md/beos/bfile.c b/nsprpub/pr/src/md/beos/bfile.c
index 38da1f33caeb..6fd6cce93fd9 100644
--- a/nsprpub/pr/src/md/beos/bfile.c
+++ b/nsprpub/pr/src/md/beos/bfile.c
@@ -673,6 +673,10 @@ _MD_pr_poll(PRPollDesc *pds, PRIntn npds, PRIntervalTime timeout)
 				}
 			}
 		}
+		else
+		{
+			pd->out_flags = 0;
+		}
 	}
 
 	if (0 != ready) return ready;  /* no need to block */
diff --git a/nsprpub/pr/src/md/os2/os2poll.c b/nsprpub/pr/src/md/os2/os2poll.c
index da477b1bbfc2..0b9c0de6a8bd 100644
--- a/nsprpub/pr/src/md/os2/os2poll.c
+++ b/nsprpub/pr/src/md/os2/os2poll.c
@@ -214,6 +214,10 @@ PRInt32 _PR_MD_PR_POLL(PRPollDesc *pds, PRIntn npds, PRIntervalTime timeout)
                 }
             }
         }
+        else
+        {
+            pd->out_flags = 0;
+        }
     }
 
     if (0 != ready)
diff --git a/nsprpub/pr/src/md/unix/uxpoll.c b/nsprpub/pr/src/md/unix/uxpoll.c
index 56a0d3dc2657..c504cd4d5f43 100644
--- a/nsprpub/pr/src/md/unix/uxpoll.c
+++ b/nsprpub/pr/src/md/unix/uxpoll.c
@@ -173,6 +173,7 @@ static PRInt32 NativeThreadPoll(
         {
             /* make poll() ignore this entry */
             syspoll[index].fd = -1;
+            pds[index].out_flags = 0;
         }
     }
 
@@ -384,6 +385,10 @@ static PRInt32 NativeThreadSelect(
                 }
             }
         }
+        else
+        {
+            pd->out_flags = 0;
+        }
     }
 
     if (0 != ready) return ready;  /* no need to block */
diff --git a/nsprpub/pr/src/md/windows/w32poll.c b/nsprpub/pr/src/md/windows/w32poll.c
index 2747a0408f51..9c4836f3d6b4 100644
--- a/nsprpub/pr/src/md/windows/w32poll.c
+++ b/nsprpub/pr/src/md/windows/w32poll.c
@@ -223,6 +223,10 @@ PRInt32 _PR_MD_PR_POLL(PRPollDesc *pds, PRIntn npds, PRIntervalTime timeout)
                 }
             }
         }
+        else
+        {
+            pd->out_flags = 0;
+        }
     }
 
     if (0 != ready) return ready;  /* no need to block */
diff --git a/nsprpub/pr/src/pthreads/ptio.c b/nsprpub/pr/src/pthreads/ptio.c
index 2934449129ec..65ba62549571 100644
--- a/nsprpub/pr/src/pthreads/ptio.c
+++ b/nsprpub/pr/src/pthreads/ptio.c
@@ -3824,6 +3824,7 @@ static PRInt32 _pr_poll_with_poll(
             {
                 /* make poll() ignore this entry */
                 syspoll[index].fd = -1;
+                pds[index].out_flags = 0;
             }
         }
         if (0 == ready)
@@ -4085,6 +4086,10 @@ static PRInt32 _pr_poll_with_select(
                     }
                 }
             }
+            else
+            {
+                pds[index].out_flags = 0;
+            }
         }
         if (0 == ready)
         {