4 a handy guide for creating useful bug reports
8 It's hard to imagine, but sometimes, xscreensaver has bugs. This
9 document gives some hints for isolating them; the more information
10 you can give me about the problem, the better the odds that I'll be
11 able to fix it. But, if you don't have time to go through these
12 steps, please report the bug anyway -- even vague bug reports can
13 be better than no bug report at all.
18 What are you doing here? Go read README, and then the man page.
22 Do you have the most recent version? Go make sure.
23 http://www.jwz.org/xscreensaver/.
27 If you get an error running the `configure' script, the first thing
28 you should try is deleting the `config.cache' file, and running again.
29 If that doesn't fix it, the information I'll need to see to make
30 sense of the problem is the following:
32 * everything printed to stderr/stdout when you first ran
35 * the contents of the `config.log' file.
37 Make sure you blow away the config.cache file before regenerating
38 this info, or else the `config.log' file will be mostly empty/useless.
40 Experience seems to show that the most common configure problem is
41 that sites have gcc installed, but installed improperly. The
42 configure script will always try to use gcc in preference to another
43 compiler if gcc exists, so if gcc exists but is broken, it won't
44 work. Your options are:
46 * get someone to fix the gcc installation;
48 * rearrange your $PATH so that the broken gcc is not on it;
50 * or pass $CC in the environment, like so:
52 csh: setenv CC cc ; ./configure
53 sh: CC=cc ; ./configure
55 Before doing this, you'll need to nuke `config.cache'.
57 If you get errors about not being able to find Motif or Gtk (the
58 Xm/ or gtk/ header files), and you can't find them on your system,
59 then your system is horked and your vendor is lame. Perhaps the
60 problem is that you don't have some kind of ``development option''
61 installed. Xt/is free and available on all systems; Xm/ (Motif)
62 is available on all commercial systems except SunOS 4.x and some
63 early releases of Solaris. Linux and other free Unixes systems
64 usually come with Gtk, but a Motif clone is also available from
65 http://www.lesstif.org/.
69 For runtime errors, it's important to keep in mind that there are
70 two parts to xscreensaver: there is the screensaver driver process
71 (the daemon that detects idleness, deals with locking, and launches
72 the demos); and there are the demos themselves (independent programs
73 that draw pretty pictures.)
75 * Compile with `make CFLAGS=-g' (so that if you get a core
76 dump, there will be debugging info in it.)
78 * What platform are you running on? What does the included
79 `./config.guess' shell script print?
81 * Is the problem in the driver (`xscreensaver'), the GUI
82 (`xscreensaver-demo'), or in the graphics hacks?
84 * If the problem is in the GUI, was it built using
85 Motif, Lesstif, or Gtk? Which version?
87 * If the problem is in one (or more) of the hacks, which ones?
88 If you're not sure, try running `xscreensaver-demo' to go
89 through the list of them and see which work and which don't.
91 * Does the problem occur when running that hack by hand, in
92 its own window (i.e., when started with no command-line args)?
94 * Does the problem occur when running that hack by hand, on
95 the root window (i.e., when started with the `-root' option)?
97 * IMPORTANT: What visual are you using? Send the output of
98 the `xdpyinfo' command.
100 * Does the problem go away if you give the program a different
101 `-visual' argument? (For example, `-visual pseudocolor' or
102 `-visual truecolor'.)
104 * IMPORTANT: What exactly goes wrong? No, I don't know what
105 you mean by "crash". Does it print an "X Error" and exit?
106 Does it dump core? Does it go into a loop?
108 * If it dumps core, what does the core file say? Run the
109 program under a debugger, and show me the stack trace.
110 To extract a stack trace from a core file with gdb, do this:
112 gdb ./the-program ./core
115 To extract a stack trace from a core file with dbx, do this:
117 dbx ./the-program ./core
120 If the bottom few lines of the output don't include the functions
121 `main_loop()' and `main()', then something went wrong, and the
122 core file is bogus. If the lines it prints out contain only
123 question marks, then the core file is bogus. Are you sure the
124 core file came from that program? Did you compile with -g, as
125 explained above? If you don't compile with -g, the core file
126 won't have any information in it.
128 Never ever ever mail me (or anyone) a core file. They are huge,
129 and are only meaningful on the machine that generated them, with
130 the exact executable that generated them, neither of which anyone
131 but you has access to. Don't mail me a core file unless you're
132 also planning on mailing me your computer.
134 * If it gets an X error, where did it come from? Run
135 xscreensaver with the `-sync' command-line option. When `-sync'
136 is used, X errors will cause xscreensaver to dump a core file.
137 Look at the core file with a debugger and show me the stack trace,
138 as above: I need to know where in xscreensaver that X error came
141 If the problem is with the xscreensaver process itself, or if you
142 can't figure out which demo is causing the problem, or if you can't
143 reproduce the problem in isolation, then you will need to turn on
144 and examine the debugging output of the driver process.
146 * Start `xscreensaver' with the command-line arguments
150 This will cause it to write a lot of debugging info to the stderr
151 of the xscreensaver process (the `-verbose' option turns on the
152 diagnostics; the `-no-capture' option prevents the data from being
153 displayed on the screensaver window as well.)
155 You also might want to use the `-timestamp' option, which will
156 cause the xscreensaver messages to include the time at which
159 * If the problem is intermittent, you might want to capture the
160 log information to a file and examine it later. For example,
161 you could start it from your login script like this (csh syntax):
163 ( cd ~/src/xscreensaver/ ; \
164 xscreensaver -sync -verbose -timestamp -no-capture \
167 * Hackers only: If you're feeling adventurous enough to run gdb
168 on the xscreensaver driver process itself, make sure you've
169 read the commentary at the top of xscreensaver.c.
171 -----------------------------------------------------------------------------
172 http://www.jwz.org/xscreensaver/
173 Jamie Zawinski <jwz@jwz.org>
174 -----------------------------------------------------------------------------