R Gurus / Ninjas / Wizards:
On both R 2.12 (Windows 7) and R 2.13 (OS X 10.5) I have tried the
following:
1. In one instance of R open a socket via:
s1 <- socketConnection(server=TRUE, open="a+b", port=31415,
blocking=FALSE);
2. And in another instance I do the following:
s2 <- socketConnection(open="a+b", port=31415, blocking=FALSE);
And so I have two processes communicating with sockets. Now, say on s1,
I use
socketSelect(list(s1),,0) # Session 1
and it returns FALSE, so nothing is there. Then on s2 I send data with
writeBin("Hi", con=s2, size=1) # Session 2
and now
socketSelect(list(s1),,0) # Session 1 -> TRUE
returns TRUE, so I can read two bytes
readBin(s1, what=raw(), n=3, size=1) # Session 1 -> 68, 69, 00
and select then returns false again
socketSelect(list(s1),,0) # Session 1 -> FALSE
Now here's my problem - it seems that if s2 closes, then socketSelect
always returns true
close(s2) # Session 2
socketSelect(list(s1),,0) # Session 1 -> TRUE
and so if I use readBin session 1 blocks:
readBin(s1, what=raw(), n=3, size=1) # Session 1, blocks *FOREVER*
I have tried setting options()$timeout before and after creating the
sockets, and that doesn't work. Is there some aspect of sockets in R
that I am missing? As long as it didn't block and I could just have my
own timeout kick out of a while loop I would be happy, but I don't seem
to have that option. Is there any way to make readBin not block?
~Matthew Maycock
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