2 files changed, 46 insertions, 0 deletions
diff --git a/include/ruby/internal/abi.h b/include/ruby/internal/abi.h
new file mode 100644
index 0000000000..78ed4c1875
--- /dev/null
+++ b/include/ruby/internal/abi.h
@@ -0,0 +1,45 @@
+#ifndef RUBY_ABI_H
+#define RUBY_ABI_H
+
+/* This number represents Ruby's ABI version.
+ *
+ * In development Ruby, it should be bumped every time an ABI incompatible
+ * change is introduced. This will force other developers to rebuild extension
+ * gems.
+ *
+ * The following cases are considered as ABI incompatible changes:
+ * - Changing any data structures.
+ * - Changing macros or inline functions causing a change in behavior.
+ * - Deprecating or removing function declarations.
+ *
+ * The following cases are NOT considered as ABI incompatible changes:
+ * - Any changes that does not involve the header files in the `include`
+ *   directory.
+ * - Adding macros, inline functions, or function declarations.
+ * - Backwards compatible refactors.
+ * - Editing comments.
+ *
+ * In released versions of Ruby, this number should not be changed since teeny
+ * versions of Ruby should guarantee ABI compatibility.
+ */
+#define RUBY_ABI_VERSION 0
+
+/* Windows does not support weak symbols so ruby_abi_version will not exist
+ * in the shared library. */
+#if defined(HAVE_FUNC_WEAK) && !defined(_WIN32) && !defined(__MINGW32__)
+# define RUBY_DLN_CHECK_ABI 1
+#else
+# define RUBY_DLN_CHECK_ABI 0
+#endif
+
+#if RUBY_DLN_CHECK_ABI
+
+RUBY_FUNC_EXPORTED unsigned long long __attribute__((weak))
+ruby_abi_version(void)
+{
+    return RUBY_ABI_VERSION;
+}
+
+#endif
+
+#endif
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index f35d13685c..108127a93c 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -23,6 +23,7 @@
 #include <stdarg.h>
 
 #include "defines.h"
+#include "ruby/internal/abi.h"
 #include "ruby/internal/anyargs.h"
 #include "ruby/internal/arithmetic.h"
 #include "ruby/internal/core.h"