first re-commit.

pigpio-master/EXAMPLES/CPP/ROTARY_ENCODER/test_rotary_encoder.cpp

@@ -0,0 +1,45 @@
+#include <iostream>
+
+#include <pigpio.h>
+
+#include "rotary_encoder.hpp"
+
+/*
+
+REQUIRES
+
+A rotary encoder contacts A and B connected to separate gpios and
+the common contact connected to Pi ground.
+
+TO BUILD
+
+g++ -o rot_enc_cpp test_rotary_encoder.cpp rotary_encoder.cpp -lpigpio -lrt
+
+TO RUN
+
+sudo ./rot_enc_cpp
+
+*/
+
+void callback(int way)
+{
+   static int pos = 0;
+
+   pos += way;
+
+   std::cout << "pos=" << pos << std::endl;
+}
+
+int main(int argc, char *argv[])
+{
+   if (gpioInitialise() < 0) return 1;
+
+   re_decoder dec(7, 8, callback);
+
+   sleep(3000);
+
+   dec.re_cancel();
+
+   gpioTerminate();
+}
+