minimal ruby c eval

test.c

# compile with gcc test.c `pkg-config ruby --cflags --libs` -o test.out
#include <stdio.h>
#include <ruby.h>

int main(void) {
  int result;
  const char code[];

  ruby_init();
  ruby_init_loadpath();

  code = "p 'HELLO'";
  rb_eval_string_protect(code, &result);

  ruby_cleanup(0);
  return result;
}