correct initialization of Ruby interpreter

main.c

@@ -1,10 +1,32 @@
+#include <stdio.h>
 #include "ruby.h"
 
+RUBY_GLOBAL_SETUP
+
+static VALUE eval(const char * string)
+{
+    int state;
+    VALUE v = rb_eval_string_protect(string, &state);
+    if (state != 0)
+    {
+        fprintf(stderr, "rb_eval_string_protect() returned state %d!\n", state);
+        rb_set_errinfo(Qnil);
+    }
+    return v;
+}
+
 int main(int argc, char *argv[])
 {
-    ruby_init();
-    ruby_init_loadpath();
-    VALUE v = rb_eval_string("3 + 8");
-    printf("v: %d\n", FIX2INT(v));
+    ruby_sysinit(&argc, &argv);
+    {
+        RUBY_INIT_STACK;
+        ruby_init();
+        ruby_init_loadpath();
+        VALUE v = eval("3 + 8");
+        printf("v: %d\n", FIX2INT(v));
+        eval("File.open('out.txt', 'w') {|fh| fh.puts 'hello!'}");
+        eval("puts 'Hello, World!'");
+        ruby_finalize();
+    }
     return 0;
 }