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   REPLYADDR not@telling.you.invalid   
   REPLYTO 3:770/3.0 UUCP   
   MSGID: <66b008f5@news.ausics.net> 224774f9   
   REPLY:  51fa60dd   
   PID: SoupGate-Win32 v1.05   
   Josef M?llers  wrote:   
   > I used to use the sysfs interface to the GPIO pins (/sys/class/gpio) but   
   > I understand that is deprecated nowadays. So I tried to switch to lgpio   
   > which looks OK.   
      
   Personally I switched to using the "gpio" command that's one of the   
   example programs included with the bcm2835 library. If you're just   
   trying to build C programs to replace the /sys/class/gpio devices   
   in a shell script, it's an existing option. It does have some bugs   
   though.   
      
   https://www.airspayce.com/mikem/bcm2835/   
      
   See examples/gpio/gpio.c in the source code.   
      
   > However, I have problems writing and reading back pin   
   > states from different programs.   
   > [snip]   
   > However ... When I set the pin's state to "1", I still read back "0"!   
   >   
   > What am I doing wrong? Thanks in advance for any pointers.   
      
   At a GUESS, you're reading the input buffer instead of the output   
   buffer. In output mode the input is disabled and always reads zero   
   or is meaningless.   
      
   Unfortunately I've forgotten whether this is the case with the Pi,   
   or at least where to look to confirm I'm not mis-remembering, so   
   check for yourself. But this is a common way for IO hardware to   
   work.   
      
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