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Reading from the parallel port

Getting direct access to the parallel port from scripting languages like PHP, Perl and Python can sometimes be a pain. You can compile a trivial helper program in C that you can then call from your script to read the port.

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/io.h> #define portaddress 0x378 main(void) { int value; ioperm(portaddress,3,1); value = inb(portaddress + 1); printf("%x\n", value); }

Save that snippet into a file such as "lptin.c", then compile it like this:

gcc -O lptin.c -o lptin

Then run it with root privileges to read the current value of the port:

sudo ./lptin