mention stdin, if filename is NULL

diff --git a/doc/libmagic.man b/doc/libmagic.man
index e38ba515e132d930cda9459829c840edb1c739b4..570678d0304292cea8c4262e4d2bc6a84c8f5023 100644 (file)
--- a/doc/libmagic.man
+++ b/doc/libmagic.man
@@ -111,6 +111,9 @@ The
 function returns a textual description of the contents of the
 .Ar filename
 argument, or NULL if an error occurred.
+If the
+.Ar filename
+is NULL, then stdin is used.
 .Pp
 The
 .Fn magic_buffer