Initial commit.

example/dog.h

@@ -0,0 +1,57 @@
+/*
+ * This file is part of libooc.
+ * https://xw3.org/hanez/libooc
+ *
+ * Copyright 2026 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ */
+
+#ifndef DOG_H
+#define DOG_H
+
+#include "animal.h"
+
+typedef struct Dog Dog;
+
+/*
+ * Derived class.
+ *
+ * The embedded Animal comes first, so a Dog pointer can be handed to any
+ * function expecting an Animal, and Dog adds a breed of its own.
+ *
+ * Two things follow from that ordering. The ooc_object header inside Animal
+ * stays at offset zero, where the library looks for it, and the upcast is a
+ * no-op cast because both addresses are the same -- which is what lets speak()
+ * in dog.c cast its Animal * back to a Dog * without arithmetic. The cost is
+ * that a Dog may not add a member of its own before the base.
+ *
+ * The struct holds no destructor of its own; the one Dog registers lives in
+ * Dog_class and releases both the breed and Animal's name.
+ */
+struct Dog {
+    Animal animal;
+    char  *breed;
+};
+
+/*
+ * Dog's runtime type record, the value ooc_new() takes.
+ *
+ * Its `super` is Animal_class, so a Dog inherits Animal's fields, and its
+ * `size` is sizeof(Dog), so the allocation has room for the breed.
+ */
+extern const ooc_class Dog_class;
+
+/*
+ * Create a Dog named `name` of the given `breed` and return it, or NULL.
+ *
+ * The result has a reference count of one, so ownership is the caller's and it
+ * must reach ooc_release() eventually. Returns NULL if any step of the
+ * construction fails, leaving nothing to release.
+ *
+ * The object is a Dog and answers to Dog's `speak`, whether it is later reached
+ * through a Dog * or an Animal *.
+ */
+Dog *dog_new(const char *name, int age, const char *breed);
+
+#endif /* DOG_H */