Adding C++ version

examples/libraryExample/main_bad.cc

+#include <iostream>
+
+int main(void) {
+  std::printf("The square of 2.0 is %f\n", squared(2.0));
+
+  return 0;
+}

examples/libraryExample/main_correct.cc

+#include "mymath.h"
+#include <iostream>
+
+int main(void) {
+  std::printf("The square of 2.0 is %f\n", squared(2.0));
+
+  return 0;
+}

examples/libraryExample/my_math_library/Makefile

+CC ?= gcc
+CFLAGS += -fPIC
+LDFLAGS += -shared
+
+all: libmymath.so
+
+libmymath.so: mymath.o
+	$(CC) $(LDFLAGS) $(CFLAGS) -o $@ $^
+
+clean:
+	rm -f *.o libmymath.so

examples/libraryExample/mylibrary/mymath.c → examples/libraryExample/my_math_library/mymath.c

 #include "mymath.h"
 
-double squared(double x) {
-  return x*x;
-}
+double squared(double x) { return x * x; }

examples/libraryExample/my_math_library/mymath.h

+#ifndef MYMATH_H
+#define MYMATH_H
+
+// clang-format off
+
+#if defined(__cplusplus)
+extern "C"
+#endif
+
+double squared(double x);
+
+#endif // MYMATH_H

examples/libraryExample/mylibrary/Makefile

-CC=gcc
-
-.PHONY: clean, distclean
-
-library: libmymath.so clean
-
-mymath.o: mymath.c
-	$(CC) -fPIC -c $<
-
-libmymath.so: mymath.o
-	$(CC) -shared -o $@ $^
-
-clean:
-	rm -f *.o
-
-distclean: clean
-	rm -f *.so

examples/libraryExample/mylibrary/mymath.h

-#ifndef MYMATH_H_
-#define MYMATH_H_
-
-double squared(double x);
-
-#endif // MYMATH_H_