title: C functions invoked as threads - Linux userland program
body: <p>I'm writing a linux daemon in C which gets values from an ADC by SPI interface (ioctl). The SPI (spidev - userland) seems to be a bit unstable and freezes the daemon at random times.</p>
  
  <p>I need to have some better control of the calls to the functions getting the values, and I was thinking of making it as a thread which I could wait for to finish and get the return value and if it times out assume that it froze and kill it without this new thread taking down the daemon itself. Then I could apply measures like resetting the ADC before restarting. Is this possible?</p>
  
  <p>Pseudo example of what I want to achieve: </p>
  
  <p>(function <strong>int get_adc_value(int adc_channel, float *value)</strong> )</p>
  
  <ol>
  <li>pid = thread( get_adc_value(1,&amp;value); //makes thread calling the function</li>
  <li>wait_until_finish(pid, timeout); //waits until function finishes/timesout</li>
  <li>if(timeout) kill pid, start over //if thread do not return in given time, kill it (it is frozen)</li>
  <li>else if return value sane, continue //if successful, handle return variable value and continue</li>
  </ol>
  
  <p>Thanks for any input on the matter, examples highly appreciated!</p>