+#define ASYNC_STATUS_UNSUPPORTED 0
+#define ASYNC_STATUS_ERR 1
+#define ASYNC_STATUS_OK 2
+#define ASYNC_STATUS_EAGAIN 3
+
+int ASYNC_init_thread(size_t max_size, size_t init_size);
+void ASYNC_cleanup_thread(void);
+
+#ifdef OSSL_ASYNC_FD
+ASYNC_WAIT_CTX *ASYNC_WAIT_CTX_new(void);
+void ASYNC_WAIT_CTX_free(ASYNC_WAIT_CTX *ctx);
+int ASYNC_WAIT_CTX_set_wait_fd(ASYNC_WAIT_CTX *ctx, const void *key,
+ OSSL_ASYNC_FD fd,
+ void *custom_data,
+ void (*cleanup)(ASYNC_WAIT_CTX *, const void *,
+ OSSL_ASYNC_FD, void *));
+int ASYNC_WAIT_CTX_get_fd(ASYNC_WAIT_CTX *ctx, const void *key,
+ OSSL_ASYNC_FD *fd, void **custom_data);
+int ASYNC_WAIT_CTX_get_all_fds(ASYNC_WAIT_CTX *ctx, OSSL_ASYNC_FD *fd,
+ size_t *numfds);
+int ASYNC_WAIT_CTX_get_callback(ASYNC_WAIT_CTX *ctx,
+ ASYNC_callback_fn *callback,
+ void **callback_arg);
+int ASYNC_WAIT_CTX_set_callback(ASYNC_WAIT_CTX *ctx,
+ ASYNC_callback_fn callback,
+ void *callback_arg);
+int ASYNC_WAIT_CTX_set_status(ASYNC_WAIT_CTX *ctx, int status);
+int ASYNC_WAIT_CTX_get_status(ASYNC_WAIT_CTX *ctx);
+int ASYNC_WAIT_CTX_get_changed_fds(ASYNC_WAIT_CTX *ctx, OSSL_ASYNC_FD *addfd,
+ size_t *numaddfds, OSSL_ASYNC_FD *delfd,
+ size_t *numdelfds);
+int ASYNC_WAIT_CTX_clear_fd(ASYNC_WAIT_CTX *ctx, const void *key);
+#endif