Document that the initial quantity for QSem and QSemN must be >= 0

[ghc-base.git] / Control / Concurrent / QSemN.hs

diff --git a/Control/Concurrent/QSemN.hs b/Control/Concurrent/QSemN.hs
index 7ee6142..991b0d5 100644 (file)
--- a/Control/Concurrent/QSemN.hs
+++ b/Control/Concurrent/QSemN.hs
@@ -35,6 +35,7 @@ newtype QSemN = QSemN (MVar (Int,[(Int,MVar ())]))
 INSTANCE_TYPEABLE0(QSemN,qSemNTc,"QSemN")
 
 -- |Build a new 'QSemN' with a supplied initial quantity.
+--  The initial quantity must be at least 0.
 newQSemN :: Int -> IO QSemN
 newQSemN initial =
     if initial < 0