Raspberry Pi GPIO

Richard Gaskin ambassador at fourthworld.com
Fri Jun 10 13:26:28 EDT 2016

Earlier I wrote:

 > What is "the file method"?  How do I treat GPIO connections as file
 > paths?  Somewhere in /proc?
 > Earlier you wrote:
 >     Look at the comments in the library it self for how to solve
 >     the Accessing the GPIO (of a raspberry pi) without "sudo" problem.
 > The stack script isn't very big, and perhaps I'm just pre-coffee but I
 > couldn't find anything there about sudo.
 > Where should I be looking?

Coffee helped.  I was looking in "the stack itself", and then for a 
"Hardware" section, overlooking the "Raspberry Pi" section right there 
in front of me once I thought to scroll down to look for it. :)

It seems the "files" method is using a mounted virtual file system, 
similar to /proc or /run/shm, which are actually elements in RAM 
accessible through file-like paths in keeping with the Unix tradition of 
"everything is a file".  This appears to be the common method for 
obtaining GPIO data:

Thanks for maintaining the Master Lib - with what's there I should be 
able to poke around and get what I need.

One last question for now:  is there any mechanism accessible to use in 
LiveCode that allows our app to subscribe to events in /sys/class/gpio, 
or do we need to poll for changes?

  Richard Gaskin
  Fourth World Systems
  Software Design and Development for the Desktop, Mobile, and the Web
  Ambassador at FourthWorld.com                http://www.FourthWorld.com

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