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_SOURCESis an environment variable you can set to get debugging output on a particular collection of source files.
DEBUG_SOURCES=allwill give you more information than you ever wanted about what LessTif is doing internally. You can also set
DEBUG_SOURCESto 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=MainW.c:FileSB.c export DEBUG_SOURCESIf your shell is csh or tcsh, you can set
setenv DEBUG_SOURCES "MainW.c:FileSB.c"If you unset
DEBUG_SOURCESor 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
will produce debugging output for all sources, but Vendor.c!
DEBUG_SOURCEScan exceed the line buffering of typical terminal settings. The environmental variable
DEBUG_FILEcan 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_SOURCESis 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=FOCUSwill 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
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
#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
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)
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
start the server itself.
Sometimes you may not even need to have it running on a "real" X server, then you can use
(X virtual frame buffer).