How to read from serial port without blocking?

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1

Hello,

Can anyone tell me how I can read from the serial port without the read
function blocking, or if it does, it only blocks for a very short time? The
1/10th of a second available in readcond() is still too slow. I need to get
it up to a rate of approximately 100Hz (0.01sec). Alternatively, do I need
to have another process or thread continually waking up the blocked read
function?

Thanks for your help.

Shayne

2

Shayne Powell wrote:

Hello,

Can anyone tell me how I can read from the serial port without the read
function blocking, or if it does, it only blocks for a very short time? The
1/10th of a second available in readcond() is still too slow. I need to get
it up to a rate of approximately 100Hz (0.01sec). Alternatively, do I need
to have another process or thread continually waking up the blocked read
function?

Have your tried opening the port non-block (see docs for open, flag O_NONBLOCK).
I have never needed to do this, but I have always assumed it would work if I did.

Rennie

3

Shayne Powell <s2.powell@qut.edu.au> wrote:

Hello,

Can anyone tell me how I can read from the serial port without the read
function blocking, or if it does, it only blocks for a very short time? The
1/10th of a second available in readcond() is still too slow. I need to get
it up to a rate of approximately 100Hz (0.01sec). Alternatively, do I need
to have another process or thread continually waking up the blocked read
function?

Open with O_NONBLOCK, then use either select() or io_notify() to get
notification when there is data available to read() (rather than polling).

-David

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