On Sun, Dec 16, 2012 at 12:49 AM, Simon Urbanek
<simon.urba...@r-project.org> wrote:
> Note that you're not using the payload of the pipe at all, so you
> could simply just send a single byte (not that it matters but you
> don't need the 16-byte packets).
>
> Also you don't want to send anything if the signal is already
> enqueued, it's pointless to try to send more (you could clog the
> pipe), so simply use a flag that you set on write and reset it on
> read -- if that flag is set you don't write anything. That will make
> sure that you get only one trigger even if more signals arrived
> while R is busy. Everything is synchronous here so no need to
> worry.
>
> Finally, I wouldn't mess with the signal all the time - just keep it
> active without touching it and use a flag to avoid re-entrance if
> you really think it's necessary.
Thanks for the additional suggestions. It's even better now:
void handle_winch(int sig){
if(fired)
return;
fired = 1;
char buf[16];
*buf = 0;
if(write(ofd, buf, 1) <= 0)
REprintf("setwidth error: write <= 0\n");
}
static void uih(void *data) {
char buf[16];
if(read(ifd, buf, 16) == 0)
REprintf("setwidth error: read = 0\n");
R_ToplevelExec(setwidth_Set, NULL);
fired = 0;
}
Best,
Jakson
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