-------- Forwarded Message -------- Subject: Simple changes to select(2) and pipe(7) Date: Sun, 6 Nov 2022 19:53:35 +0100 From: J.H. vd Water <henri.van.de.water@xxxxxxxxx> To: mtk.manpages@xxxxxxxxx CC: alx.manpages@xxxxxxxxx Hi, I am following the instructions from here: - https://www.kernel.org/doc/man-pages/reporting_bugs.html "Simple one-line or two-line errors ... can be reported by sending an email message to the maintainers ..." man 2 select ... DESCRIPTION reads: "select() allows a program to monitor multiple file descriptors, waiting until one or more of the file descriptors become "ready" for some class of I/O operation (e.g., input possible). A file descriptor is considered ready if it is possible to perform a corresponding I/O operation (e.g., read(2), or a sufficiently small write(2)) without blocking." I suggest to add the following line: "However, note that select(2) will block on the read end of a pipe/fifo, if the write end of the pipe/fifo has never been opened before, unlike read(2) (read(2) will always return with zero if the write end of the pipe/fifo is closed - see pipe(7) where the text starts with I/O on pipes and fifos). --- man 7 pipe ... where the paragraph start with "I/O on pipes and FIFOs": "If a process attempts to read from an empty pipe, then read(2) will block until data is available." I suggest to change the above line as follows: "If a process attempts to read from an empty pipe while the write end is open, then read(2) will block (in case the O_NONBLOCK openfile status flag has been disabled) until data is available; however, if the write end of the pipe is closed and the pipe is empty, then read(2) will return with zero." Regards, Henri
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