diff --git a/include/openssl/dh.h b/include/openssl/dh.h
index d781789..2c49fc8 100644
--- a/include/openssl/dh.h
+++ b/include/openssl/dh.h
@@ -193,7 +193,7 @@
  * See |ex_data.h| for details. */
 
 OPENSSL_EXPORT int DH_get_ex_new_index(long argl, void *argp,
-                                       CRYPTO_EX_new *new_func,
+                                       CRYPTO_EX_unused *unused,
                                        CRYPTO_EX_dup *dup_func,
                                        CRYPTO_EX_free *free_func);
 OPENSSL_EXPORT int DH_set_ex_data(DH *d, int idx, void *arg);
diff --git a/include/openssl/dsa.h b/include/openssl/dsa.h
index bd16395..2045fe7 100644
--- a/include/openssl/dsa.h
+++ b/include/openssl/dsa.h
@@ -302,7 +302,7 @@
  * See |ex_data.h| for details. */
 
 OPENSSL_EXPORT int DSA_get_ex_new_index(long argl, void *argp,
-                                        CRYPTO_EX_new *new_func,
+                                        CRYPTO_EX_unused *unused,
                                         CRYPTO_EX_dup *dup_func,
                                         CRYPTO_EX_free *free_func);
 OPENSSL_EXPORT int DSA_set_ex_data(DSA *d, int idx, void *arg);
diff --git a/include/openssl/ec_key.h b/include/openssl/ec_key.h
index 5226796..afd95d6 100644
--- a/include/openssl/ec_key.h
+++ b/include/openssl/ec_key.h
@@ -226,7 +226,7 @@
  * These functions are wrappers. See |ex_data.h| for details. */
 
 OPENSSL_EXPORT int EC_KEY_get_ex_new_index(long argl, void *argp,
-                                           CRYPTO_EX_new *new_func,
+                                           CRYPTO_EX_unused *unused,
                                            CRYPTO_EX_dup *dup_func,
                                            CRYPTO_EX_free *free_func);
 OPENSSL_EXPORT int EC_KEY_set_ex_data(EC_KEY *r, int idx, void *arg);
diff --git a/include/openssl/ex_data.h b/include/openssl/ex_data.h
index c0d3773..0e88c0f 100644
--- a/include/openssl/ex_data.h
+++ b/include/openssl/ex_data.h
@@ -121,8 +121,8 @@
 /* ex_data is a mechanism for associating arbitrary extra data with objects.
  * For each type of object that supports ex_data, different users can be
  * assigned indexes in which to store their data. Each index has callback
- * functions that are called when a new object of that type is created, freed
- * and duplicated. */
+ * functions that are called when an object of that type is freed or
+ * duplicated. */
 
 
 typedef struct crypto_ex_data_st CRYPTO_EX_DATA;
@@ -142,7 +142,7 @@
  *
  * TODO(fork): this should follow the standard calling convention. */
 OPENSSL_EXPORT int TYPE_get_ex_new_index(long argl, void *argp,
-                                         CRYPTO_EX_new *new_func,
+                                         CRYPTO_EX_unused *unused,
                                          CRYPTO_EX_dup *dup_func,
                                          CRYPTO_EX_free *free_func);
 
@@ -160,24 +160,15 @@
 
 /* Callback types. */
 
-/* CRYPTO_EX_new is the type of a callback function that is called whenever a
- * new object of a given class is created. For example, if this callback has
- * been passed to |SSL_get_ex_new_index| then it'll be called each time an SSL*
- * is created.
+/* CRYPTO_EX_free is a callback function that is called when an object of the
+ * class is being destroyed. For example, if this callback has been passed to
+ * |SSL_get_ex_new_index| then it'll be called each time an |SSL*| is destroyed.
  *
- * The callback is passed the new object (i.e. the SSL*) in |parent|. The
+ * The callback is passed the new object (i.e. the |SSL*|) in |parent|. The
  * arguments |argl| and |argp| contain opaque values that were given to
  * |CRYPTO_get_ex_new_index|. The callback should return one on success, but
  * the value is ignored.
  *
- * TODO(fork): the |ptr| argument is always NULL, no? */
-typedef int CRYPTO_EX_new(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
-                          int index, long argl, void *argp);
-
-/* CRYPTO_EX_free is a callback function that is called when an object of the
- * class is being destroyed. See |CRYPTO_EX_new| for a discussion of the
- * arguments.
- *
  * If |CRYPTO_get_ex_new_index| was called after the creation of objects of the
  * class that this applies to then, when those those objects are destroyed,
  * this callback will be called with a NULL value for |ptr|. */
@@ -202,6 +193,13 @@
 /* CRYPTO_cleanup_all_ex_data does nothing. */
 OPENSSL_EXPORT void CRYPTO_cleanup_all_ex_data(void);
 
+
+/* Private structures. */
+
+/* CRYPTO_EX_unused is a placeholder for an unused callback. It is aliased to
+ * int to ensure non-NULL callers fail to compile rather than fail silently. */
+typedef int CRYPTO_EX_unused;
+
 struct crypto_ex_data_st {
   STACK_OF(void) *sk;
 };
diff --git a/include/openssl/rsa.h b/include/openssl/rsa.h
index e624f7c..7f8cfe3 100644
--- a/include/openssl/rsa.h
+++ b/include/openssl/rsa.h
@@ -386,7 +386,7 @@
  * See |ex_data.h| for details. */
 
 OPENSSL_EXPORT int RSA_get_ex_new_index(long argl, void *argp,
-                                        CRYPTO_EX_new *new_func,
+                                        CRYPTO_EX_unused *unused,
                                         CRYPTO_EX_dup *dup_func,
                                         CRYPTO_EX_free *free_func);
 OPENSSL_EXPORT int RSA_set_ex_data(RSA *r, int idx, void *arg);
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index b61df9d..885dea2 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -2548,7 +2548,7 @@
 OPENSSL_EXPORT int SSL_set_ex_data(SSL *ssl, int idx, void *data);
 OPENSSL_EXPORT void *SSL_get_ex_data(const SSL *ssl, int idx);
 OPENSSL_EXPORT int SSL_get_ex_new_index(long argl, void *argp,
-                                        CRYPTO_EX_new *new_func,
+                                        CRYPTO_EX_unused *unused,
                                         CRYPTO_EX_dup *dup_func,
                                         CRYPTO_EX_free *free_func);
 
@@ -2557,14 +2557,14 @@
 OPENSSL_EXPORT void *SSL_SESSION_get_ex_data(const SSL_SESSION *session,
                                              int idx);
 OPENSSL_EXPORT int SSL_SESSION_get_ex_new_index(long argl, void *argp,
-                                                CRYPTO_EX_new *new_func,
+                                                CRYPTO_EX_unused *unused,
                                                 CRYPTO_EX_dup *dup_func,
                                                 CRYPTO_EX_free *free_func);
 
 OPENSSL_EXPORT int SSL_CTX_set_ex_data(SSL_CTX *ctx, int idx, void *data);
 OPENSSL_EXPORT void *SSL_CTX_get_ex_data(const SSL_CTX *ctx, int idx);
 OPENSSL_EXPORT int SSL_CTX_get_ex_new_index(long argl, void *argp,
-                                            CRYPTO_EX_new *new_func,
+                                            CRYPTO_EX_unused *unused,
                                             CRYPTO_EX_dup *dup_func,
                                             CRYPTO_EX_free *free_func);
 
diff --git a/include/openssl/x509.h b/include/openssl/x509.h
index da569e8..483c5de 100644
--- a/include/openssl/x509.h
+++ b/include/openssl/x509.h
@@ -787,7 +787,7 @@
  * |x|. */
 OPENSSL_EXPORT X509 *X509_up_ref(X509 *x);
 
-OPENSSL_EXPORT int X509_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
+OPENSSL_EXPORT int X509_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
 	     CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func);
 OPENSSL_EXPORT int X509_set_ex_data(X509 *r, int idx, void *arg);
 OPENSSL_EXPORT void *X509_get_ex_data(X509 *r, int idx);
diff --git a/include/openssl/x509_vfy.h b/include/openssl/x509_vfy.h
index c11820b..b39ef49 100644
--- a/include/openssl/x509_vfy.h
+++ b/include/openssl/x509_vfy.h
@@ -498,7 +498,7 @@
 OPENSSL_EXPORT int	X509_STORE_set_default_paths(X509_STORE *ctx);
 #endif
 
-OPENSSL_EXPORT int X509_STORE_CTX_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
+OPENSSL_EXPORT int X509_STORE_CTX_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
 	CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func);
 OPENSSL_EXPORT int	X509_STORE_CTX_set_ex_data(X509_STORE_CTX *ctx,int idx,void *data);
 OPENSSL_EXPORT void *	X509_STORE_CTX_get_ex_data(X509_STORE_CTX *ctx,int idx);