1 files changed, 4 insertions, 1 deletions

diff --git a/zlib.h b/zlib.h
index afa3d5a9..8ffc8de8 100644
--- a/zlib.h
+++ b/zlib.h
@@ -795,7 +795,10 @@ ZEXTERN int ZEXPORT deflatePending(z_streamp strm,
    or bits are Z_NULL, then those values are not set.
 
      deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
-   stream state was inconsistent.
+   stream state was inconsistent.  If an int is 16 bits and memLevel is 9, then
+   it is possible for the number of pending bytes to not fit in an unsigned. In
+   that case Z_BUF_ERROR is returned and *pending is set to the maximum value
+   of an unsigned.
  */
 
 ZEXTERN int ZEXPORT deflateUsed(z_streamp strm,