There is a good section in bugs.html describing tracking down bugs in _any_ X based app.
Don't forget about "cvs log"!!!! The comments on previous commits can be very helpful, especially if you're new to the game.
DEBUG_SOURCES is an environment variable you can set
to get debugging output on a particular collection of source files.
DEBUG_SOURCES=all will
give you more information than you ever wanted about what LessTif is
doing internally. You can also set DEBUG_SOURCES to a
single file, or a list of files separated by colons ':'.
The ".c" postfix is optional here.
If your shell is sh, bash, or ksh, you can for example
set DEBUG_SOURCES by
DEBUG_SOURCES=MainW.c:FileSB.c export DEBUG_SOURCESIf your shell is csh or tcsh, you can set
DEBUG_SOURCES by
setenv DEBUG_SOURCES "MainW.c:FileSB.c"If you unset
DEBUG_SOURCES or set it to
"none" then no debugging output will be produced.
To block single files from producing debugging output, you
may add a "-" prefix to their entry. Obviously this
makes only sense if used in conjunction with the
"all" keyword:
DEBUG_SOURCES=all:-Vendor
will produce debugging output for all sources, but Vendor.c!
DEBUG_SOURCES
can exceed the line buffering of typical terminal settings. The environmental
variable DEBUG_FILE can be used to direct the output to a file
instead of stdout.
An alternate method is to run the tests as follows:
DEBUG_SOURCES=MainW.c:FileSB.c ./test1 2>&1 | tee debug.logThe advantage of this is that you also get to see the messages on the screen as well as in a file.
DEBUG_SOURCES is not limited to file names.
In reality it can be any string that matches what is in the source
for the _LtDebug() call. For example, DEBUG_SOURCES=FOCUS will
print debug info related to menu focus events, regardless of the file the
statement is in. There are some more in there also. Usually relating to
specific problems involving many different files. To find out what is
available try:
grep _LtDebug *.c | grep -v __FILE__
DEBUG_REDIRECT_XMWARNING.
Output of _XmWarning() and equivalent functions (XmeWarning(), etc.)
is then sent to the content of DEBUG_FILE
SIGBREAK, SIGUNUSED, SIGUSR1, SIGUSR2, SIGUSR3
#include <XmI/DebugUtil.h> extern Boolean _LtDebugInit(void);Call to initialize the debugging subsystem. Useful if called before any other library calls are done.
#include <XmI/DebugUtil.h> extern void _LtDebugSet(Boolean flag);Explicitly turn the debugging on/off according to
flag.
#include <XmI/DebugUtil.h> extern void _LtDebugToggle(void);Toggles the debugging system on/off.
test/.
Since even the most seemingly trivial change can often have unexpected
consequences, we recommend running the testall script under
test/ before and after applying a patch, to make sure that you
haven't broken anything else with your fix.
In these test programs, there is data that is labeled "expected".
Where do these values come from?
I guess I should answer this. They come from Jon :) Okay, sometimes I make them
also. The PrintDetails call that you see in the test code will print out the
Expected data in a format that can be cut'n pasted into the source, if the
second arg is NULL. So, we have Motif generate the Expected data for us. The
values are _very_ dependant on the default font in use. As long as you match
the font that is used to generate the Expected values the results are usually
right on. In a few cases we haven't been able to get an exact match. If we are
off by just a pixel or so, the application resource "*geometrySlop" can be set
to a value that will accept the error, and report success. In the cases where
the slop is not 0, it is also printed out with the results. The most recent
test results can also be viewed by pointing your web browser to
http://www.lesstif.org/test-results/
(may be old stuff)
In the test/common directory there is a library that is
linked with each of the test programs. In here you will find a replacement
for XtAppMainLoop(). Our version allows the test apps to exit with a status
that indicates success or failure. This is where the PrintDetails function
referred to above lives.
Nothing in this library relies on Motif, so that they function the same
whether the test apps are linked with LessTif or Motif.
This is probably also a good time to mention that all of the tests can
be compiled and linked with Motif as well as LessTif. By typing
make motif-testsin any of the test directories all the tests in that directory will be compiled and linked with Motif, assuming it is available. Therefore test1 will be the test compiled and linked with LessTif, test1.motif will be the same code compiled and linked with Motif. You can also build individual tests with
make test1.motifThe test library also includes a bunch of functions to simulate button, presses, pointer movement, and other things necessary for automated testing.
The best thing about the tests is that they tell you whether everything it was meant to test worked. For an example, take a look at rowcolumn/test51. Try remembering to do all that everytime you make a change!!!!
Really, the best way to fix a bug, and have it stay fixed, is to write a test and have it included in the test tree. Once a test has passed, a change to the library will not be accepted if it causes a previously passing test to fail. Well, it won't be accepted easily anyway :)
If you're hunting for bugs in mwm (our window manager) you have
several options: either you start a normal X11 session on your system,
e.g. on DISPLAY :1 if you have already one :0. Since you may not
need any fancy setup, starting the X server directly
may work and then you run mwm from an arbitrary terminal,
probably inside a debugger. Being non-root on un*x systems
you have to use /usr/X11/bin/Xwrapper to
start the server itself.
Sometimes you may not even need to have it running on a
"real" X server, then you can use Xvfb
(X virtual frame buffer).
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