Re: [Cppunit-devel] Signal handling in Linux

[Baptiste L. <gai...@fr...>]

So If I understood thing well, the only hope that remains would compiler
specific. VC++ has such a thing, have you found anything like that on gcc ?
(I guess not, but...)

In the meantime, I think I'll add a VerboseTestProgressListener:
startTest(): print test name
failure(): print ':' and 'E' or 'F'
endTest(): new line

Baptiste.

----- Original Message -----
From: "Robert Wenner" <ro...@po...>
To: "Baptiste Lepilleur" <gai...@fr...>;
<cpp...@li...>
Sent: Monday, April 15, 2002 8:33 AM
Subject: Re: [Cppunit-devel] Signal handling in Linux


> On Saturday 13 April 2002 11:28, Baptiste Lepilleur wrote:
> > Is it possible to wrap the signal logic into a class (even if it use
> > global variable) ? I'm planning to add a feature to add 'custom'
> > exception support (export not based on std::exception) to CppUnit.
>
> As far as I found something on the web on the topic of signal handling
> and C++: don't do it.
> Std C++ sticks to the old C behaviour of signal handling.
> That means use of C++ features will result in undefined behaviour;
> especially use of RTTI, member variables and exceptions.
> IMHO the best way to solve the signal problems is to set a global
> variable in the signal handler and return. The calling program (in
> case of CppUnit) the framework has to check that variable.
> Having the signal wrapper class use a list of received signals would
> also be possible to throw multiple exceptions (if desired).
> Ignoring some signals (such as SIG_SEGV) is considered dangerous
> as the program may be left in an undefined state (e.g. what is the
> result from a divide by zero?). This may be no problem with some
> short test cases, though.
>
> > To do that, I just call a must on a class with the Test to run and
> > the TestResult which 'protect ' the test run. In your case, that
> > would means trapping the signal, and throwing adding a failure to
> > TestResult.
> I tried a little with setting the signal handler in setUp and checking
> the global variable in tearDown, but signals behaved really strange
> on my machine (examples for a SEGV by wrong pointer access).
> - Ignoring (SIG_IGN setting ) the signal (or using no handler) crashes
> the program (the default behaviour for unhandled signals)
> - Catching the signal causes the handler to execute and after that
> crash the program
> - Catching the signal and re-installing the signal handler (it is
> uninstalled by default according to the man page) or not using the
> ONESHOT option in sa_flags results in endless signals received ->
> program hangs.
>
> > I'm really interessed into this, because VC++ does this automatically
> > for us in debug mode. This is not the case on Unix, and as such does
> > not provide a consistent behavior across plateform. As a consequence,
> > on Unix, you would need a TestListener that print the test name
> > before running the test, just to now which test failed...
> IMHO the C++ std is somewhat lazy / minimalistic here. :-(
> By time C++ should drop these old C garbage.
> Anyway  I would be really interestedin a soultion, too.
>
> Robert
>