Making fifo work (Linux)

Your problem seems to be unfamiliarity with this operating-system-specific feature. You should be reading the OS documentation (e.g. "man fifo" and learning how to use the feature in general before using it in R. (Hint: off-topic here.)

Some words to the wise: Make sure you test with two processes, one for reading, one for writing (this is not a storage medium, it is an inter-process communication mechanism). Make sure you define a specific number of lines (e.g. 1) when you read unless you want to wait until the writing process closes the fifo.
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Friends

I need to get R reading from a fifo. I want it to block till there is
some
data in the fifo, consume what input it gets there, do some thing with
it
then loop back and block again.

Very simple.  Yes?  No.

The example in the documentation works OK..

      zz <- fifo("foo-fifo", "w+")
      writeLines("abc", zz)
      print(readLines(zz))
      close(zz)
      unlink("foo-fifo")

But when I tryu my code to *read* and *block*, id does not work.

P <- "Myfoofifo"
C <- fifo(P, "r", blocking=TRUE)

If Myfoofifo does not exist this has an error:

C <- fifo(P, "r", blocking=TRUE)

Error in fifo(P, "r", blocking = TRUE) : cannot open the connection
In addition: Warning message:
In fifo(P, "r", blocking = TRUE) : cannot open fifo 'Myfoofifo'

C <- fifo(P, "w+", blocking=TRUE)

succeeds but a read...

Z <- readLines(C)

hangs.  Writing to Myfoofifo from other programmes, opening closing
even
deleting it makes no difference.

I am stuck.  I can find no pertinent  examples.  What can I do?

Worik

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