>From POSIX: "If the timeout interval expires without the specified condition
>being true for any of the specified file descriptors, the objects pointed to
>by the readfds, writefds, and errorfds arguments shall have all bits set to 0."
If your select() timeouts on first loop iteration for any reason, then it will
timeout forever as you give it back all-zeroes descriptor set to monitor.
Best Regards,
Juha Niskanen
________________________________
From: Daniel Pereira Carvalho <daniel...@gmail.com>
Sent: Friday, November 20, 2020 7:26 PM
To: dev@nuttx.apache.org <dev@nuttx.apache.org>
Subject: Re: select()/pselect() function
I will try pool() and see if the problem persists.
Thanks
Daniel Pereira de Carvalho
Em sex., 20 de nov. de 2020 às 14:18, Gregory Nutt <spudan...@gmail.com>
escreveu:
> Okay, I got that wrong. I seldom used select(), it is just an
> additional layer on top of poll() which is much more efficient.
>
> On 11/20/2020 11:13 AM, Daniel Pereira Carvalho wrote:
> > Hi Greg,
> >
> > Thanks for the answer. I don't understand why I should use 1 instead of
> > fs + 1. The documentation says
> >
> > "nfds This argument should be set to the highest-numbered file descriptor
> > in any of the three sets, plus 1. "
> >
> > In the portserial.c nfds was set to fd + 1
> >
> > Daniel Pereira de Carvalho
> >
> >
> > Em sex., 20 de nov. de 2020 às 14:04, Gregory Nutt <spudan...@gmail.com>
> > escreveu:
> >
> >>> fd = open("/dev/ttyS1", O_RDWR | O_NOCTTY);
> >> ...
> >>> s_rc = select(fd + 1, &rset, NULL, NULL, &tv);
> >> The first argument should be 1, not fd + 1
> >>
> >>
> >>
>
