diff --git a/zlib.h b/zlib.h
index d85d7c2..6728d89 100644
--- a/zlib.h
+++ b/zlib.h
@@ -1174,7 +1174,9 @@ ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
 
      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
    enough memory, Z_BUF_ERROR if there was not enough room in the output
-   buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
+   buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.  In
+   the case where there is not enough room, uncompress() will fill the output
+   buffer with the uncompressed data up to that point.
 */
 
                         /* gzip file access functions */