--- a/Semaphore.st	Tue Oct 12 16:50:50 1999 +0200
+++ b/Semaphore.st	Tue Oct 12 18:23:22 1999 +0200
@@ -625,7 +625,8 @@
      The seconds-argument may be a float (i.e. use 0.1 for a 100ms timeout).
      With zero timeout, this can be used to poll a semaphore (returning
      the receiver if the semaphore is available, nil if not).
-     However, polling is not the intended use of semaphores, though."
+     However, polling is not the intended use of semaphores, though.
+     If seconds is nil, wait without timeout."
 
     |activeProcess timeoutOccured wasBlocked unblock now endTime|
 
@@ -637,18 +638,18 @@
      things will go mad ... (especially be careful when adding a debugPrint-here)
     "
     count ~~ 0 ifTrue:[
-	count := count - 1.
-	count == 0 ifTrue:[
-	    lastOwnerID := Processor activeProcessId.
-	].
-	^ self
+        count := count - 1.
+        count == 0 ifTrue:[
+            lastOwnerID := Processor activeProcessId.
+        ].
+        ^ self
     ].
 
     "
      with zero-timeout, this is a poll
     "
     seconds = 0 ifTrue:[
-	^ nil
+        ^ nil
     ].
 
     activeProcess := Processor activeProcess.
@@ -658,11 +659,13 @@
     "
      calculate the end-time
     "
-    now := OperatingSystem getMillisecondTime.
-    endTime := OperatingSystem millisecondTimeAdd:now and:(seconds * 1000).
+    seconds notNil ifTrue:[
+        now := OperatingSystem getMillisecondTime.
+        endTime := OperatingSystem millisecondTimeAdd:now and:(seconds * 1000).
 
-    unblock := [timeoutOccured := true. Processor resume:activeProcess].
-    Processor addTimedBlock:unblock for:activeProcess atMilliseconds:endTime.
+        unblock := [timeoutOccured := true. Processor resume:activeProcess].
+        Processor addTimedBlock:unblock for:activeProcess atMilliseconds:endTime.
+    ].
 
     "
      need a while-loop here, since more than one process may
@@ -671,34 +674,37 @@
      suspend.
     "
     [count == 0] whileTrue:[
-	waitingProcesses add:activeProcess.
+        waitingProcesses add:activeProcess.
 
-	timeoutOccured := false.
-	"
-	 for some more descriptive info in processMonitor ...
-	 ... set the state to #wait (instead of #suspend)
-	"
-	[
-	    activeProcess suspendWithState:#wait.
-	] valueOnUnwindDo:[
-	    unblock := nil.
-	    waitingProcesses removeIdentical:activeProcess ifAbsent:[].
-	    wasBlocked ifFalse:[OperatingSystem unblockInterrupts].
-	].
+        timeoutOccured := false.
+        "
+         for some more descriptive info in processMonitor ...
+         ... set the state to #wait (instead of #suspend)
+        "
+        [
+            activeProcess suspendWithState:#wait.
+        ] valueOnUnwindDo:[
+            unblock := nil.
+            waitingProcesses removeIdentical:activeProcess ifAbsent:[].
+            wasBlocked ifFalse:[OperatingSystem unblockInterrupts].
+        ].
 
-	waitingProcesses removeIdentical:activeProcess ifAbsent:[].
-	timeoutOccured ifTrue:[
-	    wasBlocked ifFalse:[OperatingSystem unblockInterrupts].
-	    unblock := nil.
-	    ^ nil
-	].
+        waitingProcesses removeIdentical:activeProcess ifAbsent:[].
+        timeoutOccured ifTrue:[
+            wasBlocked ifFalse:[OperatingSystem unblockInterrupts].
+            unblock := nil.
+            ^ nil
+        ].
     ].
-    Processor removeTimedBlock:unblock.
-    unblock := nil.
+
+    unblock notNil ifTrue:[
+        Processor removeTimedBlock:unblock.
+        unblock := nil.
+    ].
 
     count := count - 1.
     count == 0 ifTrue:[
-	lastOwnerID := Processor activeProcessId.
+        lastOwnerID := Processor activeProcessId.
     ].
     wasBlocked ifFalse:[OperatingSystem unblockInterrupts].
     ^ self
@@ -710,5 +716,5 @@
 !Semaphore class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/Semaphore.st,v 1.55 1999-08-25 16:21:24 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Semaphore.st,v 1.56 1999-10-12 16:23:22 cg Exp $'
 ! !