ffi working. got a feel for it

Makefile

@@ -1,4 +1,4 @@
-.PHONY: all clean test pipe named-pipe
+.PHONY: all clean test pipe named-pipe ffi
 .ONESHELL:
 
 all: clean
@@ -6,6 +6,11 @@ all: clean
 	sleep 1;
 	make test;
 	make pipe;
+	sleep 3;
+	make named-pipe;
+	sleep 3;
+	make ffi;
+	make clean;
 
 test:
 	mkdir -p test;
@@ -15,20 +20,29 @@ test:
 	# note: below line stays in root dir because no `\` at the end of previous line
 	rm -rf test;
 
-pipe:
+pipe: clean
 	cd pipe;
 	gcc test_pipe.c -o test_pipe_c_program;
 	go build -o test_pipe_go_program main.go;
 	./test_pipe_go_program
 
-named-pipe:
+named-pipe: clean
 	cd named_pipe;
 	gcc test_named_pipe_receiver.c -o test_named_pipe_receiver_c_program;
 	go build -o test_named_pipe_sender_go_program main.go;
 	./test_named_pipe_receiver_c_program & ./test_named_pipe_sender_go_program;
 
+ffi: clean
+	cd ffi;
+	gcc -c -o example.o example.c;
+	ar rcs libexample.a example.o;
+
+	go build -o test_ffi_go_program main.go;
+	./test_ffi_go_program;
+
 clean:
 	echo "cleaning..."
 	rm -rf pipe/test_pipe_c_program pipe/test_pipe_go_program
 	rm -rf named_pipe/test_named_pipe_receiver_c_program named_pipe/test_named_pipe_sender_go_program
+	rm -rf ffi/main.o ffi/libmain.a ffi/test_ffi_go_program
 

ffi/example.c

@@ -0,0 +1,7 @@
+// example.c
+#include <stdio.h>
+
+void helloFromC() {
+    printf("Hello from C!\n");
+}
+

ffi/main.go

@@ -0,0 +1,12 @@
+package main
+
+/*
+#cgo LDFLAGS: -L./ -lexample
+void helloFromC();
+*/
+import "C"
+
+func main() {
+  print("Hello from Go! calling FFI for C\n")
+  C.helloFromC()
+}