diff -up ltrace-0.7.91/options.c\~ ltrace-0.7.91/options.c
--- ltrace-0.7.91/options.c~	2013-10-22 11:54:21.000000000 +0200
+++ ltrace-0.7.91/options.c	2014-01-13 15:38:51.362221740 +0100
@@ -128,6 +128,8 @@ usage_debug(void) {
 			"\n"
 			"Debugging options are mixed using bitwise-or.\n"
 			"Note that the meanings and values are subject to change.\n"
+			"Also note that these values are used inconsistently in ltrace, and the\n"
+			"only debuglevel that you can rely on is -D77 that will show everything.\n"
 		   );
 }
 
diff -up ltrace-0.7.91/ltrace.1\~ ltrace-0.7.91/ltrace.1
--- ltrace-0.7.91/ltrace.1~	2013-10-23 17:44:13.000000000 +0200
+++ ltrace-0.7.91/ltrace.1	2014-01-13 15:51:24.236730677 +0100
@@ -1,5 +1,5 @@
 .\" -*-nroff-*-
-.\" Copyright (c) 2012, 2013 Petr Machata, Red Hat Inc.
+.\" Copyright (c) 2012,2013,2014 Petr Machata, Red Hat Inc.
 .\" Copyright (c) 1997-2005 Juan Cespedes <[email protected]>
 .\"
 .\" This program is free software; you can redistribute it and/or
@@ -118,9 +118,9 @@ Besides removing any initial underscore 
 this makes C++ function names readable.
 .IP "\-D, \-\-debug \fRmask\fI"
 Show debugging output of \fBltrace\fR itself.  \fImask\fR is a number
-with internal meaning that's not really well defined at all.
-\fImask\fR of 77 shows all debug messages, which is what you usually
-need.
+describing which debug messages should be displayed.  Use the option
+\-Dh to see what can be used, but note that currently the only
+reliable debugmask is 77, which shows all debug messages.
 .IP "\-e \fIfilter"
 A qualifying expression which modifies which library calls to trace.
 The format of the filter expression is described in the section
@@ -156,7 +156,8 @@ dependency ordering.  If you want to mak
 library are actually called, use \fB-x @\fIlibrary_pattern\fR instead.
 .IP \-L
 When no -e option is given, don't assume the default action of
-\fB@MAIN\fR.
+\fB@MAIN\fR.  In practice this means that library calls will not be
+traced.
 .IP "\-n, \-\-indent \fInr"
 Indent trace output by \fInr\fR spaces for each level of call
 nesting. Using this option makes the program flow visualization easy