diff --git a/winsup/cygserver/ChangeLog b/winsup/cygserver/ChangeLog
index 761056afa..8af654cdc 100644
--- a/winsup/cygserver/ChangeLog
+++ b/winsup/cygserver/ChangeLog
@@ -1,3 +1,8 @@
+2004-03-30  Corinna Vinschen  <corinna@vinschen.de>
+
+	* sysv_shm.cc (shmget): Allow to retrieve shared memory segments
+	by shmid when IPC_KEY_IS_SHMID is set.
+
 2004-03-02  Corinna Vinschen  <corinna@vinschen.de>
 
 	* sysv_sem.cc (semundo_adjust): Check for process id instead of
diff --git a/winsup/cygserver/sysv_shm.cc b/winsup/cygserver/sysv_shm.cc
index 70ed1a3d4..7d038f0a6 100644
--- a/winsup/cygserver/sysv_shm.cc
+++ b/winsup/cygserver/sysv_shm.cc
@@ -808,6 +808,12 @@ shmget(struct thread *td, struct shmget_args *uap)
 	mode = uap->shmflg & ACCESSPERMS;
 	if (uap->key != IPC_PRIVATE) {
 	again:
+#ifdef __CYGWIN__
+		if (uap->shmflg & IPC_KEY_IS_SHMID)
+		  segnum = shm_find_segment_by_shmid ((int) uap->key) ?
+			   IPCID_TO_IX((int) uap->key) : -1;
+		else
+#endif
 		segnum = shm_find_segment_by_key(uap->key);
 		if (segnum >= 0) {
 			error = shmget_existing(td, uap, mode, segnum);