ffi via libffi (contd)

lib/ffi/example/Makefile

@@ -0,0 +1,6 @@
+CC = gcc
+main: lib.o
+	$(CC) -shared lib.o -o libtest.so
+	
+%.o: %.c
+	$(CC)  -fPIC -c $< -o $@

lib/ffi/example/example.lua

@@ -0,0 +1,45 @@
+local ffi = require("ffi")
+local path = "/home/mrsang/Desktop/testffi/libtest.so"
+local lib = nil
+local fn = nil
+local rettype = nil
+local argtype = nil
+if ffi then
+    -- now ffi exist
+    -- try to load the test library
+    lib = ffi.dlopen(path)
+    if lib then
+        -- now try to lookup for the greet function
+        echo("looking for greet")
+        fn = ffi.dlsym(lib,"greet")
+        if fn then
+            -- now the function found
+            -- tried to called it
+            rettype = ffi.atomic_type(0) -- void
+            if rettype then
+                argtype = ffi.atomic_type(20) -- pointer
+                if(argtype) then
+                    -- call the function
+                    local r = ffi.call(rettype, {argtype}, fn, {"hello world"})
+                    if r then
+                        echo("BIG SUCCESS")
+                    else
+                        echo("HELL FAIL")
+                    end
+                else
+                    echo("argtype not found")
+                end
+            else
+                echo("return type not found")
+            end
+        else
+            echo("unable to find greet")
+        end
+       ffi.dlclose(lib)
+    else
+        echo("unable to load the lib")
+    end
+else
+    echo("cannot find ffi")
+end
+echo("end the day")

lib/ffi/example/lib.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+void greet(const char* msg)
+{
+    printf("%s\n", msg);
+}