I'm not sure you can make this work as some of the things needed
either are or should be private to the core implementation and not
available to package code. In any case I would not recommend this
approach for two reasons. First, details of what happens in
interrupt
checking are subject to change and your code would miss those changes
unless you track them carefully. More importantly, several things
here could generate an error that results in a longjmp and leaves
your
code in an unstable state.
What is needed for this is a mechanism for detecting an interrupt but
not doing the longjmp, just returning a flag that a longjmp is needed
and enough information to allow it to be made after cleanup code has
been run. This has been on my to do list for a while but getting the
semantics right is tricky and so it hasn't happened yet. Hopefully
it
will be in 2.8.0. In the interim you can cobble something together
using R_ToplevelExec, interpreting all FALSE return values as user
interrupts.
Another option, also under consideration but not available yet, is
a C
mechanism for registering cleanup operations if a longjmp occurs. A
quick and dirty version of that could be provided fairly easily but a
better version, which would be preferable in the long run, requires a
rewrite of the code that implements jumps and cleanup/on.exit
actions.
This may take a bit longer to implement.
Best,
luke
On Fri, 16 May 2008, Kjell Konis wrote:
You mean something like this (I return 1 instead of calling
onintr())? Will HAVE_AQUA and Win32 be appropriately defined when
building my package (I can't see how to check with R CMD config)?
int My_CheckUserInterrupt(void)
{
R_CheckStack();
#if ( defined(HAVE_AQUA) )
/* R_ProcessEvents() from unix/aqua.c*/
if (ptr_R_ProcessEvents)
ptr_R_ProcessEvents();
if (R_interrupts_pending)
return(1);
#elseif ( defined(Win32) )
/* R_ProcessEvents() from gnuwin32/system.c */
while (peekevent()) doevent();
if (UserBreak) {
UserBreak = FALSE;
return(1);
}
R_CallBackHook();
if(R_tcldo) R_tcldo();
#else
R_PolledEvents();
if (R_interrupts_pending)
return(1);
#endif
return(0);
}
On 16 mai 08, at 12:43, Prof Brian Ripley wrote:
On Fri, 16 May 2008, Kjell Konis wrote:
The problem is that my package uses an external pointer to keep
track of a structure created by the lp_solve library. If I use
R_CheckUserInterrupt in the lp_solve abort function it leaves
the structure in a messed-up state after an interrupt occurs. I
am not even able to free the memory allocated in the structure.
I need to be able to tell the lp_solve functions to interrupt
themselves if I am going to support interrupts at all.
I took a longer look at errors.c and it seems my solution should
work as long as neither HAVE_AQUA nor Win32 are defined. Under
the circumstances, I think that's the best I can do.
Any suggestions for a UI independent way to check for interrupts
would be appreciated.
Why not use the same code as R_CheckUserInterrupt but instead of
calling onintr, call your own interrupt routine?
Thanks,
Kjell
On 15 mai 08, at 16:41, Prof Brian Ripley wrote:
How is R_interrupts_pending going to be set?
It is set in the interrupt handler for SIGINT, but that is not
the only way to indicate an interrupt, and it is not
necessarily available to users of GUIs and embedded R.
Without servicing the GUIs all interaction will be dead,
including sending an interrrupt from menus/buttons/keyboard.
See the comment in the code for R_CheckUserInterrupt.
On Thu, 15 May 2008, Kjell Konis wrote:
Hello,
I have some native code that I would like to allow users to
interrupt. However, I would like to do it more gracefully than
with R_CheckUserInterrupt(). The solution I came up with is to
call the following abort function periodically - if it returns
1 then I clean up and return.
int __WINAPI RlpSolveAbortFunction(lprec *lp, void *userhandle)
{
if(R_interrupts_pending)
return(1);
return(0);
}
This seems to work fine on Mac (sans Aqua) and Linux. Is this
going to be portable? Also, is there anything else I need to
do? For instance set R_interrupts_pending to 0 after I
respond to it?
Thanks.
Kjell
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University of Oxford, Tel: +44 1865 272861 (self)
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Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/
~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa Phone: 319-335-3386
Department of Statistics and Fax: 319-335-3017
Actuarial Science
241 Schaeffer Hall email: [EMAIL PROTECTED]
Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu
