On 3/11/2020 9:04 PM, Åke Rehnman via Cygwin wrote:
On 2020-03-11 22:55, Brian Inglis wrote:
VMIN > 0 || VTIME > 0 implies blocking; O_NONBLOCK implies SIGIO
delivery; see:
https://www.tldp.org/HOWTO/pdf/Serial-Programming-HOWTO.pdf
https://www.cmrr.umn.edu/~strupp/serial.html
https://en.wikibooks.org/wiki/Serial_Programming/termios
also read the man pages carefully and *assume* nothing; functions
should work
*exactly* as documented: there be dragons!
According to https://www.cmrr.umn.edu/~strupp/serial.html "*Timeouts
are ignored in canonical input mode or when the/NDELAY/option is set
on the file via/open/or/fcntl/."*
This leads me to believe the current cygwin implementation is not
correct. Changing the VMIN and VTIME should have no effect on the
read() behavior if the file was opened with O_NOBLOCK.
**
Correct me if I am wrong, but O_NDELAY is not the same as O_NONBLOCK
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