R help - Sep 2003 - debugging R

To debug R "from within Xemacs" I have tried two different things: 

C-u M-x R RET - d SPC gdb RET to start an inferior R process with arguments
@option{-d gdb}

This is the way described in the official documentation of R.

and also 

M-x R and then start GUD (M-x gdb) giving the R binary (using its full path
name: /usr/bin/R ) as the program to debug. Use the program @command{ps} to find
the
process number of the currently running R process then use the attach
command in gdb to attach it to that process.

I have had problems with the last way: R freezes.

Has anyone been succesfull in debugging R in last way?

Thank you.

Francisco J Molina <fjmolina at ams.ucsc.edu> writes:
> To debug R "from within Xemacs" I have tried two different
things:
> 
> C-u M-x R RET - d SPC gdb RET to start an inferior R process with arguments
> @option{-d gdb}
> 
> This is the way described in the official documentation of R.
> 
> and also 
> 
> M-x R and then start GUD (M-x gdb) giving the R binary (using its full path
> name: /usr/bin/R ) as the program to debug. Use the program @command{ps} to
find the
> process number of the currently running R process then use the attach
> command in gdb to attach it to that process.
> 
> I have had problems with the last way: R freezes.
That is because gdb has interrupted the R process.  At this point I
usually set a breakpoint at the function of interest, go to the gdb
window and restart R by sending the 0 signal

gdb> sig 0

Then you are able to get a response in the ESS window with R.

This technique is particularly useful if you have compiled code in a
package because you can attach the package and load the shared object
before invoking the debugger.
> Has anyone been succesfull in debugging R in last way?
Yes - more times than I would care to count.