Detect a terminated pipe
On 03/14/2014 03:54 PM, Simon Urbanek wrote:
As far as R is concerned, the connection is open. In addition, pipes exist even without the process - you can close one end of a pipe and it will still exist (that?s what makes pipes useful, actually, because you can choose to close arbitrary combination of the R/W ends). Detecting that the other end of the pipe has closed is generally done by sending/receiving data to/from the end of interest - i.e. reading from a pipe that has closed the write end on the other side will yield 0 bytes read. Writing to a pipe that has closed the read end on the other side will yield SIGPIPE error (note that for text connections you have to call flush() to send the buffer):
p=pipe("true","r")
readLines(p)
character(0)
close(p)
p=pipe("true","w")
writeLines("", p)
flush(p)
Error in flush.connection(p) : ignoring SIGPIPE signal
close(p)
Thanks for your reply. I tried this in an R console and received the error, just like you described. Unfortunately, the error is not thrown when trying the same in RStudio. Any ideas? Cheers Kirill