On Dec 15, 2012, at 2:20 PM, Jakson Alves de Aquino wrote: > On Sat, Dec 15, 2012 at 1:09 PM, Simon Urbanek > <[email protected]> wrote: >> On Dec 15, 2012, at 6:36 AM, Jakson Alves de Aquino wrote: >>> I could avoid the crash if I knew that R is busy at the moment that >>> it receives the SIGWINCH. Thus my question is: Could Rstd_Busy() >>> set the value of a variable so packages like setwidth could know >>> that R is busy? >> >> You're looking at the wrong spot - the Busy callback is meant for UI >> signaling that R may enter a longer time of processing, it is not >> really an indicator that R is busy - R can be busy even without the >> busy state being signaled. > > Thanks for your suggestions! > > Although the comment above Rstd_Busy() (at src/unix/sys-std.c) says > "actions during (long) computations", the function is called whenever > any command is entered in R Console. > >> But back to your original question - there are a few spots where you >> can process you request : the most obvious one is in the ReadConsole >> callback - that callback doesn't return until the user has entered a >> line - this would be a way to a GUI to handle this. > > Both ptr_R_Busy and ptr_R_ReadConsole are declared on Rinterface.h, > but I can't use them because setwidth doesn't provide front-end to R > and Rinterface.h has the following statements: > > This header file is to provide hooks for alternative front-ends, > e.g. GUIs such as GNOME and Cocoa. [...] It should not be > included by package sources unless they are providing such a > front-end. > >> The other way is to register an input handler and signal your FD >> when you get SIGWINCH, that guarantees that your handler will be >> called as soon as possible after the signal has arrived - that is >> probably what you want (see CarbonEL for a simple example how this >> is used). > > Based on CarbolEL, I added the following to setwidth_Start() function: > > int fds[2]; > if(pipe(fds)) > Rprintf("pipe > 0\n"); > else > Rprintf("pipe = 0\n"); > ifd = fds[0]; > ofd = fds[1]; > addInputHandler(R_InputHandlers, ifd, &uih, 32); > > And, also based on CarbolEL, I created the following uih() function: > > static void uih(void *data) { > char buf[16]; > > if(read(ifd, buf, 16) == 0){ > Rprintf("read = 0 :: %s\n", buf); > Rprintf("%d written\n", write(ofd, buf, 16)); > } else { > Rprintf("read != 0\n"); > } > } > > However, the uih() function never gets called. >
You didn't provide the signal yet - you have the initialization and receiving end ready - now you need to write the piece that triggers the input. Cheers, S > Best, > > -- > Jakson Alves de Aquino > Federal University of Ceará > Social Sciences Department > www.lepem.ufc.br/aquino.php > > ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
