Blocking on serial port read/write

QNX DEVELOPERS Realtime and Embedded
1

I have few queries regarding serial port read/write:

  1. Can readcond() remain blocked eventhough the specified TIMEOUT has happened?

  2. Can write() call get blocked?

Kindly help me understand.

2
  1. Can readcond() remain blocked eventhough the specified TIMEOUT has happened?

A higher priority process in a cpu loop could prevent readcond() from returning. This is not really blocked since your thread would be in READY mode.

  1. Can write() call get blocked?

On a serial port? Sure. If you have flow control turned on, your output buffer can fill up and then you are blocked on write().