Control stript which is runing in background.
Alan Bawden
alan at csail.mit.edu
Fri Jan 1 00:23:38 EST 2021
jak <nospam at please.ty> writes:
Running the command:
$ cat bible.txt > cmdpipe & cat bible.txt > cmdpipe & cat bible.txt > cmdpipe
the three texts do not mix....
The three texts do not mix as long at the contents of bible.txt is short
enough (and provided `cat' only calls `write' once). In the POSIX
specification, the manual page for the `write' system call describes
writing to a pipe or FIFO as follows:
Write requests of {PIPE_BUF} bytes or less shall not be interleaved
with data from other processes doing writes on the same pipe. Writes
of greater than {PIPE_BUF} bytes may have data interleaved, on
arbitrary boundaries, with writes by other processes, whether or not
the O_NONBLOCK flag of the file status flags is set.
--
Alan Bawden
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