diff --git a/crypto/stack/stack.c b/crypto/stack/stack.c
index c81afcb..4f4f1df 100644
--- a/crypto/stack/stack.c
+++ b/crypto/stack/stack.c
@@ -65,16 +65,30 @@
 #include "../internal.h"
 
 
+struct stack_st {
+  // num contains the number of valid pointers in |data|.
+  size_t num;
+  void **data;
+  // sorted is non-zero if the values pointed to by |data| are in ascending
+  // order, based on |comp|.
+  int sorted;
+  // num_alloc contains the number of pointers allocated in the buffer pointed
+  // to by |data|, which may be larger than |num|.
+  size_t num_alloc;
+  // comp is an optional comparison function.
+  OPENSSL_sk_cmp_func comp;
+};
+
 // kMinSize is the number of pointers that will be initially allocated in a new
 // stack.
 static const size_t kMinSize = 4;
 
-_STACK *sk_new(OPENSSL_sk_cmp_func comp) {
-  _STACK *ret = OPENSSL_malloc(sizeof(_STACK));
+OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_cmp_func comp) {
+  OPENSSL_STACK *ret = OPENSSL_malloc(sizeof(OPENSSL_STACK));
   if (ret == NULL) {
     return NULL;
   }
-  OPENSSL_memset(ret, 0, sizeof(_STACK));
+  OPENSSL_memset(ret, 0, sizeof(OPENSSL_STACK));
 
   ret->data = OPENSSL_malloc(sizeof(void *) * kMinSize);
   if (ret->data == NULL) {
@@ -93,16 +107,16 @@
   return NULL;
 }
 
-_STACK *sk_new_null(void) { return sk_new(NULL); }
+OPENSSL_STACK *OPENSSL_sk_new_null(void) { return OPENSSL_sk_new(NULL); }
 
-size_t sk_num(const _STACK *sk) {
+size_t OPENSSL_sk_num(const OPENSSL_STACK *sk) {
   if (sk == NULL) {
     return 0;
   }
   return sk->num;
 }
 
-void sk_zero(_STACK *sk) {
+void OPENSSL_sk_zero(OPENSSL_STACK *sk) {
   if (sk == NULL || sk->num == 0) {
     return;
   }
@@ -111,21 +125,21 @@
   sk->sorted = 0;
 }
 
-void *sk_value(const _STACK *sk, size_t i) {
+void *OPENSSL_sk_value(const OPENSSL_STACK *sk, size_t i) {
   if (!sk || i >= sk->num) {
     return NULL;
   }
   return sk->data[i];
 }
 
-void *sk_set(_STACK *sk, size_t i, void *value) {
+void *OPENSSL_sk_set(OPENSSL_STACK *sk, size_t i, void *value) {
   if (!sk || i >= sk->num) {
     return NULL;
   }
   return sk->data[i] = value;
 }
 
-void sk_free(_STACK *sk) {
+void OPENSSL_sk_free(OPENSSL_STACK *sk) {
   if (sk == NULL) {
     return;
   }
@@ -133,8 +147,9 @@
   OPENSSL_free(sk);
 }
 
-void sk_pop_free_ex(_STACK *sk, OPENSSL_sk_call_free_func call_free_func,
-                    OPENSSL_sk_free_func free_func) {
+void OPENSSL_sk_pop_free_ex(OPENSSL_STACK *sk,
+                            OPENSSL_sk_call_free_func call_free_func,
+                            OPENSSL_sk_free_func free_func) {
   if (sk == NULL) {
     return;
   }
@@ -144,7 +159,7 @@
       call_free_func(free_func, sk->data[i]);
     }
   }
-  sk_free(sk);
+  OPENSSL_sk_free(sk);
 }
 
 // Historically, |sk_pop_free| called the function as |OPENSSL_sk_free_func|
@@ -154,11 +169,11 @@
   func(ptr);
 }
 
-void sk_pop_free(_STACK *sk, OPENSSL_sk_free_func free_func) {
-  sk_pop_free_ex(sk, call_free_func_legacy, free_func);
+void sk_pop_free(OPENSSL_STACK *sk, OPENSSL_sk_free_func free_func) {
+  OPENSSL_sk_pop_free_ex(sk, call_free_func_legacy, free_func);
 }
 
-size_t sk_insert(_STACK *sk, void *p, size_t where) {
+size_t OPENSSL_sk_insert(OPENSSL_STACK *sk, void *p, size_t where) {
   if (sk == NULL) {
     return 0;
   }
@@ -208,7 +223,7 @@
   return sk->num;
 }
 
-void *sk_delete(_STACK *sk, size_t where) {
+void *OPENSSL_sk_delete(OPENSSL_STACK *sk, size_t where) {
   void *ret;
 
   if (!sk || where >= sk->num) {
@@ -226,22 +241,23 @@
   return ret;
 }
 
-void *sk_delete_ptr(_STACK *sk, const void *p) {
+void *OPENSSL_sk_delete_ptr(OPENSSL_STACK *sk, const void *p) {
   if (sk == NULL) {
     return NULL;
   }
 
   for (size_t i = 0; i < sk->num; i++) {
     if (sk->data[i] == p) {
-      return sk_delete(sk, i);
+      return OPENSSL_sk_delete(sk, i);
     }
   }
 
   return NULL;
 }
 
-void sk_delete_if(_STACK *sk, OPENSSL_sk_call_delete_if_func call_func,
-                  OPENSSL_sk_delete_if_func func, void *data) {
+void OPENSSL_sk_delete_if(OPENSSL_STACK *sk,
+                          OPENSSL_sk_call_delete_if_func call_func,
+                          OPENSSL_sk_delete_if_func func, void *data) {
   if (sk == NULL) {
     return;
   }
@@ -256,8 +272,8 @@
   sk->num = new_num;
 }
 
-int sk_find(const _STACK *sk, size_t *out_index, const void *p,
-            OPENSSL_sk_call_cmp_func call_cmp_func) {
+int OPENSSL_sk_find(const OPENSSL_STACK *sk, size_t *out_index, const void *p,
+                    OPENSSL_sk_call_cmp_func call_cmp_func) {
   if (sk == NULL) {
     return 0;
   }
@@ -279,7 +295,7 @@
     return 0;
   }
 
-  if (!sk_is_sorted(sk)) {
+  if (!OPENSSL_sk_is_sorted(sk)) {
     for (size_t i = 0; i < sk->num; i++) {
       const void *elem = sk->data[i];
       if (call_cmp_func(sk->comp, &p, &elem) == 0) {
@@ -327,38 +343,40 @@
   return 0;  // Not found.
 }
 
-void *sk_shift(_STACK *sk) {
+void *OPENSSL_sk_shift(OPENSSL_STACK *sk) {
   if (sk == NULL) {
     return NULL;
   }
   if (sk->num == 0) {
     return NULL;
   }
-  return sk_delete(sk, 0);
+  return OPENSSL_sk_delete(sk, 0);
 }
 
-size_t sk_push(_STACK *sk, void *p) { return (sk_insert(sk, p, sk->num)); }
+size_t OPENSSL_sk_push(OPENSSL_STACK *sk, void *p) {
+  return OPENSSL_sk_insert(sk, p, sk->num);
+}
 
-void *sk_pop(_STACK *sk) {
+void *OPENSSL_sk_pop(OPENSSL_STACK *sk) {
   if (sk == NULL) {
     return NULL;
   }
   if (sk->num == 0) {
     return NULL;
   }
-  return sk_delete(sk, sk->num - 1);
+  return OPENSSL_sk_delete(sk, sk->num - 1);
 }
 
-_STACK *sk_dup(const _STACK *sk) {
+OPENSSL_STACK *OPENSSL_sk_dup(const OPENSSL_STACK *sk) {
   if (sk == NULL) {
     return NULL;
   }
 
-  _STACK *ret = OPENSSL_malloc(sizeof(_STACK));
+  OPENSSL_STACK *ret = OPENSSL_malloc(sizeof(OPENSSL_STACK));
   if (ret == NULL) {
     return NULL;
   }
-  OPENSSL_memset(ret, 0, sizeof(_STACK));
+  OPENSSL_memset(ret, 0, sizeof(OPENSSL_STACK));
 
   ret->data = OPENSSL_malloc(sizeof(void *) * sk->num_alloc);
   if (ret->data == NULL) {
@@ -373,7 +391,7 @@
   return ret;
 
 err:
-  sk_free(ret);
+  OPENSSL_sk_free(ret);
   return NULL;
 }
 
@@ -389,7 +407,8 @@
 }
 #endif
 
-void sk_sort(_STACK *sk, OPENSSL_sk_call_cmp_func call_cmp_func) {
+void OPENSSL_sk_sort(OPENSSL_STACK *sk,
+                     OPENSSL_sk_call_cmp_func call_cmp_func) {
   if (sk == NULL || sk->comp == NULL || sk->sorted) {
     return;
   }
@@ -418,7 +437,7 @@
   sk->sorted = 1;
 }
 
-int sk_is_sorted(const _STACK *sk) {
+int OPENSSL_sk_is_sorted(const OPENSSL_STACK *sk) {
   if (!sk) {
     return 1;
   }
@@ -426,7 +445,8 @@
   return sk->sorted || (sk->comp != NULL && sk->num < 2);
 }
 
-OPENSSL_sk_cmp_func sk_set_cmp_func(_STACK *sk, OPENSSL_sk_cmp_func comp) {
+OPENSSL_sk_cmp_func OPENSSL_sk_set_cmp_func(OPENSSL_STACK *sk,
+                                            OPENSSL_sk_cmp_func comp) {
   OPENSSL_sk_cmp_func old = sk->comp;
 
   if (sk->comp != comp) {
@@ -437,11 +457,12 @@
   return old;
 }
 
-_STACK *sk_deep_copy(const _STACK *sk, OPENSSL_sk_call_copy_func call_copy_func,
-                     OPENSSL_sk_copy_func copy_func,
-                     OPENSSL_sk_call_free_func call_free_func,
-                     OPENSSL_sk_free_func free_func) {
-  _STACK *ret = sk_dup(sk);
+OPENSSL_STACK *OPENSSL_sk_deep_copy(const OPENSSL_STACK *sk,
+                                    OPENSSL_sk_call_copy_func call_copy_func,
+                                    OPENSSL_sk_copy_func copy_func,
+                                    OPENSSL_sk_call_free_func call_free_func,
+                                    OPENSSL_sk_free_func free_func) {
+  OPENSSL_STACK *ret = OPENSSL_sk_dup(sk);
   if (ret == NULL) {
     return NULL;
   }
@@ -457,7 +478,7 @@
           call_free_func(free_func, ret->data[j]);
         }
       }
-      sk_free(ret);
+      OPENSSL_sk_free(ret);
       return NULL;
     }
   }
diff --git a/include/openssl/stack.h b/include/openssl/stack.h
index 2774e86..ce92be6 100644
--- a/include/openssl/stack.h
+++ b/include/openssl/stack.h
@@ -245,8 +245,11 @@
 
 // Private functions.
 //
-// TODO(https://crbug.com/boringssl/499): Rename to |OPENSSL_sk_foo|, after
-// external code that calls them is fixed.
+// The |sk_*| functions generated above are implemented internally using the
+// type-erased functions below. Callers should use the typed wrappers instead.
+// When using the type-erased functions, callers are responsible for ensuring
+// the underlying types are correct. Casting pointers to the wrong types will
+// result in memory errors.
 
 // OPENSSL_sk_free_func is a function that frees an element in a stack. Note its
 // actual type is void (*)(T *) for some T. Low-level |sk_*| functions will be
@@ -282,63 +285,83 @@
 typedef int (*OPENSSL_sk_call_delete_if_func)(OPENSSL_sk_delete_if_func, void *,
                                               void *);
 
-// stack_st contains an array of pointers. It is not designed to be used
+// An OPENSSL_STACK contains an array of pointers. It is not designed to be used
 // directly, rather the wrapper macros should be used.
-typedef struct stack_st {
-  // num contains the number of valid pointers in |data|.
-  size_t num;
-  void **data;
-  // sorted is non-zero if the values pointed to by |data| are in ascending
-  // order, based on |comp|.
-  int sorted;
-  // num_alloc contains the number of pointers allocated in the buffer pointed
-  // to by |data|, which may be larger than |num|.
-  size_t num_alloc;
-  // comp is an optional comparison function.
-  OPENSSL_sk_cmp_func comp;
-} _STACK;
+typedef struct stack_st OPENSSL_STACK;
 
 // The following are raw stack functions. They implement the corresponding typed
 // |sk_SAMPLE_*| functions generated by |DEFINE_STACK_OF|. Callers shouldn't be
 // using them. Rather, callers should use the typed functions.
-OPENSSL_EXPORT _STACK *sk_new(OPENSSL_sk_cmp_func comp);
-OPENSSL_EXPORT _STACK *sk_new_null(void);
-OPENSSL_EXPORT size_t sk_num(const _STACK *sk);
-OPENSSL_EXPORT void sk_zero(_STACK *sk);
-OPENSSL_EXPORT void *sk_value(const _STACK *sk, size_t i);
-OPENSSL_EXPORT void *sk_set(_STACK *sk, size_t i, void *p);
-OPENSSL_EXPORT void sk_free(_STACK *sk);
-OPENSSL_EXPORT void sk_pop_free_ex(_STACK *sk,
-                                   OPENSSL_sk_call_free_func call_free_func,
-                                   OPENSSL_sk_free_func free_func);
-OPENSSL_EXPORT size_t sk_insert(_STACK *sk, void *p, size_t where);
-OPENSSL_EXPORT void *sk_delete(_STACK *sk, size_t where);
-OPENSSL_EXPORT void *sk_delete_ptr(_STACK *sk, const void *p);
-OPENSSL_EXPORT void sk_delete_if(_STACK *sk,
-                                 OPENSSL_sk_call_delete_if_func call_func,
-                                 OPENSSL_sk_delete_if_func func, void *data);
-OPENSSL_EXPORT int sk_find(const _STACK *sk, size_t *out_index, const void *p,
-                           OPENSSL_sk_call_cmp_func call_cmp_func);
-OPENSSL_EXPORT void *sk_shift(_STACK *sk);
-OPENSSL_EXPORT size_t sk_push(_STACK *sk, void *p);
-OPENSSL_EXPORT void *sk_pop(_STACK *sk);
-OPENSSL_EXPORT _STACK *sk_dup(const _STACK *sk);
-OPENSSL_EXPORT void sk_sort(_STACK *sk, OPENSSL_sk_call_cmp_func call_cmp_func);
-OPENSSL_EXPORT int sk_is_sorted(const _STACK *sk);
-OPENSSL_EXPORT OPENSSL_sk_cmp_func sk_set_cmp_func(_STACK *sk,
-                                                   OPENSSL_sk_cmp_func comp);
-OPENSSL_EXPORT _STACK *sk_deep_copy(const _STACK *sk,
-                                    OPENSSL_sk_call_copy_func call_copy_func,
-                                    OPENSSL_sk_copy_func copy_func,
-                                    OPENSSL_sk_call_free_func call_free_func,
-                                    OPENSSL_sk_free_func free_func);
+OPENSSL_EXPORT OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_cmp_func comp);
+OPENSSL_EXPORT OPENSSL_STACK *OPENSSL_sk_new_null(void);
+OPENSSL_EXPORT size_t OPENSSL_sk_num(const OPENSSL_STACK *sk);
+OPENSSL_EXPORT void OPENSSL_sk_zero(OPENSSL_STACK *sk);
+OPENSSL_EXPORT void *OPENSSL_sk_value(const OPENSSL_STACK *sk, size_t i);
+OPENSSL_EXPORT void *OPENSSL_sk_set(OPENSSL_STACK *sk, size_t i, void *p);
+OPENSSL_EXPORT void OPENSSL_sk_free(OPENSSL_STACK *sk);
+OPENSSL_EXPORT void OPENSSL_sk_pop_free_ex(
+    OPENSSL_STACK *sk, OPENSSL_sk_call_free_func call_free_func,
+    OPENSSL_sk_free_func free_func);
+OPENSSL_EXPORT size_t OPENSSL_sk_insert(OPENSSL_STACK *sk, void *p,
+                                        size_t where);
+OPENSSL_EXPORT void *OPENSSL_sk_delete(OPENSSL_STACK *sk, size_t where);
+OPENSSL_EXPORT void *OPENSSL_sk_delete_ptr(OPENSSL_STACK *sk, const void *p);
+OPENSSL_EXPORT void OPENSSL_sk_delete_if(
+    OPENSSL_STACK *sk, OPENSSL_sk_call_delete_if_func call_func,
+    OPENSSL_sk_delete_if_func func, void *data);
+OPENSSL_EXPORT int OPENSSL_sk_find(const OPENSSL_STACK *sk, size_t *out_index,
+                                   const void *p,
+                                   OPENSSL_sk_call_cmp_func call_cmp_func);
+OPENSSL_EXPORT void *OPENSSL_sk_shift(OPENSSL_STACK *sk);
+OPENSSL_EXPORT size_t OPENSSL_sk_push(OPENSSL_STACK *sk, void *p);
+OPENSSL_EXPORT void *OPENSSL_sk_pop(OPENSSL_STACK *sk);
+OPENSSL_EXPORT OPENSSL_STACK *OPENSSL_sk_dup(const OPENSSL_STACK *sk);
+OPENSSL_EXPORT void OPENSSL_sk_sort(OPENSSL_STACK *sk,
+                                    OPENSSL_sk_call_cmp_func call_cmp_func);
+OPENSSL_EXPORT int OPENSSL_sk_is_sorted(const OPENSSL_STACK *sk);
+OPENSSL_EXPORT OPENSSL_sk_cmp_func
+OPENSSL_sk_set_cmp_func(OPENSSL_STACK *sk, OPENSSL_sk_cmp_func comp);
+OPENSSL_EXPORT OPENSSL_STACK *OPENSSL_sk_deep_copy(
+    const OPENSSL_STACK *sk, OPENSSL_sk_call_copy_func call_copy_func,
+    OPENSSL_sk_copy_func copy_func, OPENSSL_sk_call_free_func call_free_func,
+    OPENSSL_sk_free_func free_func);
+
+
+// Deprecated private functions (hidden).
+//
+// TODO(crbug.com/boringssl/499): Migrate callers to the typed wrappers, or at
+// least the new names and remove the old ones.
+
+typedef OPENSSL_STACK _STACK;
+
+OPENSSL_INLINE OPENSSL_STACK *sk_new_null(void) {
+  return OPENSSL_sk_new_null();
+}
+
+OPENSSL_INLINE size_t sk_num(const OPENSSL_STACK *sk) {
+  return OPENSSL_sk_num(sk);
+}
+
+OPENSSL_INLINE void *sk_value(const OPENSSL_STACK *sk, size_t i) {
+  return OPENSSL_sk_value(sk, i);
+}
+
+OPENSSL_INLINE void sk_free(OPENSSL_STACK *sk) { OPENSSL_sk_free(sk); }
+
+OPENSSL_INLINE size_t sk_push(OPENSSL_STACK *sk, void *p) {
+  return OPENSSL_sk_push(sk, p);
+}
+
+OPENSSL_INLINE void *sk_pop(OPENSSL_STACK *sk) { return OPENSSL_sk_pop(sk); }
 
 // sk_pop_free behaves like |sk_pop_free_ex| but performs an invalid function
 // pointer cast. It exists because some existing callers called |sk_pop_free|
 // directly.
 //
 // TODO(davidben): Migrate callers to bssl::UniquePtr and remove this.
-OPENSSL_EXPORT void sk_pop_free(_STACK *sk, OPENSSL_sk_free_func free_func);
+OPENSSL_EXPORT void sk_pop_free(OPENSSL_STACK *sk,
+                                OPENSSL_sk_free_func free_func);
+
 
 #if !defined(BORINGSSL_NO_CXX)
 extern "C++" {
@@ -368,153 +391,154 @@
 #define BORINGSSL_DEFINE_STACK_TRAITS(name, type, is_const)
 #endif
 
-#define BORINGSSL_DEFINE_STACK_OF_IMPL(name, ptrtype, constptrtype)           \
-  /* We disable MSVC C4191 in this macro, which warns when pointers are cast  \
-   * to the wrong type. While the cast itself is valid, it is often a bug     \
-   * because calling it through the cast is UB. However, we never actually    \
-   * call functions as |OPENSSL_sk_cmp_func|. The type is just a type-erased  \
-   * function pointer. (C does not guarantee function pointers fit in         \
-   * |void*|, and GCC will warn on this.) Thus we just disable the false      \
-   * positive warning. */                                                     \
-  OPENSSL_MSVC_PRAGMA(warning(push))                                          \
-  OPENSSL_MSVC_PRAGMA(warning(disable : 4191))                                \
-                                                                              \
-  DECLARE_STACK_OF(name)                                                      \
-                                                                              \
-  typedef void (*sk_##name##_free_func)(ptrtype);                             \
-  typedef ptrtype (*sk_##name##_copy_func)(constptrtype);                     \
-  typedef int (*sk_##name##_cmp_func)(constptrtype const *,                   \
-                                      constptrtype const *);                  \
-  typedef int (*sk_##name##_delete_if_func)(ptrtype, void *);                 \
-                                                                              \
-  OPENSSL_INLINE void sk_##name##_call_free_func(                             \
-      OPENSSL_sk_free_func free_func, void *ptr) {                            \
-    ((sk_##name##_free_func)free_func)((ptrtype)ptr);                         \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE void *sk_##name##_call_copy_func(                            \
-      OPENSSL_sk_copy_func copy_func, const void *ptr) {                      \
-    return (void *)((sk_##name##_copy_func)copy_func)((constptrtype)ptr);     \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE int sk_##name##_call_cmp_func(OPENSSL_sk_cmp_func cmp_func,  \
-                                               const void *const *a,          \
-                                               const void *const *b) {        \
-    /* The data is actually stored as |void*| pointers, so read the pointer   \
-     * as |void*| and then pass the corrected type into the caller-supplied   \
-     * function, which expects |constptrtype*|. */                            \
-    constptrtype a_ptr = (constptrtype)*a;                                    \
-    constptrtype b_ptr = (constptrtype)*b;                                    \
-    return ((sk_##name##_cmp_func)cmp_func)(&a_ptr, &b_ptr);                  \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE int sk_##name##_call_delete_if_func(                         \
-      OPENSSL_sk_delete_if_func func, void *obj, void *data) {                \
-    return ((sk_##name##_delete_if_func)func)((ptrtype)obj, data);            \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE STACK_OF(name) *sk_##name##_new(sk_##name##_cmp_func comp) { \
-    return (STACK_OF(name) *)sk_new((OPENSSL_sk_cmp_func)comp);               \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE STACK_OF(name) *sk_##name##_new_null(void) {                 \
-    return (STACK_OF(name) *)sk_new_null();                                   \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE size_t sk_##name##_num(const STACK_OF(name) *sk) {           \
-    return sk_num((const _STACK *)sk);                                        \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE void sk_##name##_zero(STACK_OF(name) *sk) {                  \
-    sk_zero((_STACK *)sk);                                                    \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE ptrtype sk_##name##_value(const STACK_OF(name) *sk,          \
-                                           size_t i) {                        \
-    return (ptrtype)sk_value((const _STACK *)sk, i);                          \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE ptrtype sk_##name##_set(STACK_OF(name) *sk, size_t i,        \
-                                         ptrtype p) {                         \
-    return (ptrtype)sk_set((_STACK *)sk, i, (void *)p);                       \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE void sk_##name##_free(STACK_OF(name) *sk) {                  \
-    sk_free((_STACK *)sk);                                                    \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE void sk_##name##_pop_free(STACK_OF(name) *sk,                \
-                                           sk_##name##_free_func free_func) { \
-    sk_pop_free_ex((_STACK *)sk, sk_##name##_call_free_func,                  \
-                   (OPENSSL_sk_free_func)free_func);                          \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE size_t sk_##name##_insert(STACK_OF(name) *sk, ptrtype p,     \
-                                           size_t where) {                    \
-    return sk_insert((_STACK *)sk, (void *)p, where);                         \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE ptrtype sk_##name##_delete(STACK_OF(name) *sk,               \
-                                            size_t where) {                   \
-    return (ptrtype)sk_delete((_STACK *)sk, where);                           \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE ptrtype sk_##name##_delete_ptr(STACK_OF(name) *sk,           \
-                                                constptrtype p) {             \
-    return (ptrtype)sk_delete_ptr((_STACK *)sk, (const void *)p);             \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE void sk_##name##_delete_if(                                  \
-      STACK_OF(name) *sk, sk_##name##_delete_if_func func, void *data) {      \
-    sk_delete_if((_STACK *)sk, sk_##name##_call_delete_if_func,               \
-                 (OPENSSL_sk_delete_if_func)func, data);                      \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE int sk_##name##_find(const STACK_OF(name) *sk,               \
-                                      size_t *out_index, constptrtype p) {    \
-    return sk_find((const _STACK *)sk, out_index, (const void *)p,            \
-                   sk_##name##_call_cmp_func);                                \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE ptrtype sk_##name##_shift(STACK_OF(name) *sk) {              \
-    return (ptrtype)sk_shift((_STACK *)sk);                                   \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE size_t sk_##name##_push(STACK_OF(name) *sk, ptrtype p) {     \
-    return sk_push((_STACK *)sk, (void *)p);                                  \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE ptrtype sk_##name##_pop(STACK_OF(name) *sk) {                \
-    return (ptrtype)sk_pop((_STACK *)sk);                                     \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE STACK_OF(name) *sk_##name##_dup(const STACK_OF(name) *sk) {  \
-    return (STACK_OF(name) *)sk_dup((const _STACK *)sk);                      \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE void sk_##name##_sort(STACK_OF(name) *sk) {                  \
-    sk_sort((_STACK *)sk, sk_##name##_call_cmp_func);                         \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE int sk_##name##_is_sorted(const STACK_OF(name) *sk) {        \
-    return sk_is_sorted((const _STACK *)sk);                                  \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE sk_##name##_cmp_func sk_##name##_set_cmp_func(               \
-      STACK_OF(name) *sk, sk_##name##_cmp_func comp) {                        \
-    return (sk_##name##_cmp_func)sk_set_cmp_func((_STACK *)sk,                \
-                                                 (OPENSSL_sk_cmp_func)comp);  \
-  }                                                                           \
-                                                                              \
-  OPENSSL_INLINE STACK_OF(name) *sk_##name##_deep_copy(                       \
-      const STACK_OF(name) *sk, sk_##name##_copy_func copy_func,              \
-      sk_##name##_free_func free_func) {                                      \
-    return (STACK_OF(name) *)sk_deep_copy(                                    \
-        (const _STACK *)sk, sk_##name##_call_copy_func,                       \
-        (OPENSSL_sk_copy_func)copy_func, sk_##name##_call_free_func,          \
-        (OPENSSL_sk_free_func)free_func);                                     \
-  }                                                                           \
-                                                                              \
+#define BORINGSSL_DEFINE_STACK_OF_IMPL(name, ptrtype, constptrtype)            \
+  /* We disable MSVC C4191 in this macro, which warns when pointers are cast   \
+   * to the wrong type. While the cast itself is valid, it is often a bug      \
+   * because calling it through the cast is UB. However, we never actually     \
+   * call functions as |OPENSSL_sk_cmp_func|. The type is just a type-erased   \
+   * function pointer. (C does not guarantee function pointers fit in          \
+   * |void*|, and GCC will warn on this.) Thus we just disable the false       \
+   * positive warning. */                                                      \
+  OPENSSL_MSVC_PRAGMA(warning(push))                                           \
+  OPENSSL_MSVC_PRAGMA(warning(disable : 4191))                                 \
+                                                                               \
+  DECLARE_STACK_OF(name)                                                       \
+                                                                               \
+  typedef void (*sk_##name##_free_func)(ptrtype);                              \
+  typedef ptrtype (*sk_##name##_copy_func)(constptrtype);                      \
+  typedef int (*sk_##name##_cmp_func)(constptrtype const *,                    \
+                                      constptrtype const *);                   \
+  typedef int (*sk_##name##_delete_if_func)(ptrtype, void *);                  \
+                                                                               \
+  OPENSSL_INLINE void sk_##name##_call_free_func(                              \
+      OPENSSL_sk_free_func free_func, void *ptr) {                             \
+    ((sk_##name##_free_func)free_func)((ptrtype)ptr);                          \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE void *sk_##name##_call_copy_func(                             \
+      OPENSSL_sk_copy_func copy_func, const void *ptr) {                       \
+    return (void *)((sk_##name##_copy_func)copy_func)((constptrtype)ptr);      \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE int sk_##name##_call_cmp_func(OPENSSL_sk_cmp_func cmp_func,   \
+                                               const void *const *a,           \
+                                               const void *const *b) {         \
+    /* The data is actually stored as |void*| pointers, so read the pointer    \
+     * as |void*| and then pass the corrected type into the caller-supplied    \
+     * function, which expects |constptrtype*|. */                             \
+    constptrtype a_ptr = (constptrtype)*a;                                     \
+    constptrtype b_ptr = (constptrtype)*b;                                     \
+    return ((sk_##name##_cmp_func)cmp_func)(&a_ptr, &b_ptr);                   \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE int sk_##name##_call_delete_if_func(                          \
+      OPENSSL_sk_delete_if_func func, void *obj, void *data) {                 \
+    return ((sk_##name##_delete_if_func)func)((ptrtype)obj, data);             \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE STACK_OF(name) *sk_##name##_new(sk_##name##_cmp_func comp) {  \
+    return (STACK_OF(name) *)OPENSSL_sk_new((OPENSSL_sk_cmp_func)comp);        \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE STACK_OF(name) *sk_##name##_new_null(void) {                  \
+    return (STACK_OF(name) *)OPENSSL_sk_new_null();                            \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE size_t sk_##name##_num(const STACK_OF(name) *sk) {            \
+    return OPENSSL_sk_num((const OPENSSL_STACK *)sk);                          \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE void sk_##name##_zero(STACK_OF(name) *sk) {                   \
+    OPENSSL_sk_zero((OPENSSL_STACK *)sk);                                      \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE ptrtype sk_##name##_value(const STACK_OF(name) *sk,           \
+                                           size_t i) {                         \
+    return (ptrtype)OPENSSL_sk_value((const OPENSSL_STACK *)sk, i);            \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE ptrtype sk_##name##_set(STACK_OF(name) *sk, size_t i,         \
+                                         ptrtype p) {                          \
+    return (ptrtype)OPENSSL_sk_set((OPENSSL_STACK *)sk, i, (void *)p);         \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE void sk_##name##_free(STACK_OF(name) *sk) {                   \
+    OPENSSL_sk_free((OPENSSL_STACK *)sk);                                      \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE void sk_##name##_pop_free(STACK_OF(name) *sk,                 \
+                                           sk_##name##_free_func free_func) {  \
+    OPENSSL_sk_pop_free_ex((OPENSSL_STACK *)sk, sk_##name##_call_free_func,    \
+                           (OPENSSL_sk_free_func)free_func);                   \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE size_t sk_##name##_insert(STACK_OF(name) *sk, ptrtype p,      \
+                                           size_t where) {                     \
+    return OPENSSL_sk_insert((OPENSSL_STACK *)sk, (void *)p, where);           \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE ptrtype sk_##name##_delete(STACK_OF(name) *sk,                \
+                                            size_t where) {                    \
+    return (ptrtype)OPENSSL_sk_delete((OPENSSL_STACK *)sk, where);             \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE ptrtype sk_##name##_delete_ptr(STACK_OF(name) *sk,            \
+                                                constptrtype p) {              \
+    return (ptrtype)OPENSSL_sk_delete_ptr((OPENSSL_STACK *)sk,                 \
+                                          (const void *)p);                    \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE void sk_##name##_delete_if(                                   \
+      STACK_OF(name) *sk, sk_##name##_delete_if_func func, void *data) {       \
+    OPENSSL_sk_delete_if((OPENSSL_STACK *)sk, sk_##name##_call_delete_if_func, \
+                         (OPENSSL_sk_delete_if_func)func, data);               \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE int sk_##name##_find(const STACK_OF(name) *sk,                \
+                                      size_t *out_index, constptrtype p) {     \
+    return OPENSSL_sk_find((const OPENSSL_STACK *)sk, out_index,               \
+                           (const void *)p, sk_##name##_call_cmp_func);        \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE ptrtype sk_##name##_shift(STACK_OF(name) *sk) {               \
+    return (ptrtype)OPENSSL_sk_shift((OPENSSL_STACK *)sk);                     \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE size_t sk_##name##_push(STACK_OF(name) *sk, ptrtype p) {      \
+    return OPENSSL_sk_push((OPENSSL_STACK *)sk, (void *)p);                    \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE ptrtype sk_##name##_pop(STACK_OF(name) *sk) {                 \
+    return (ptrtype)OPENSSL_sk_pop((OPENSSL_STACK *)sk);                       \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE STACK_OF(name) *sk_##name##_dup(const STACK_OF(name) *sk) {   \
+    return (STACK_OF(name) *)OPENSSL_sk_dup((const OPENSSL_STACK *)sk);        \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE void sk_##name##_sort(STACK_OF(name) *sk) {                   \
+    OPENSSL_sk_sort((OPENSSL_STACK *)sk, sk_##name##_call_cmp_func);           \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE int sk_##name##_is_sorted(const STACK_OF(name) *sk) {         \
+    return OPENSSL_sk_is_sorted((const OPENSSL_STACK *)sk);                    \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE sk_##name##_cmp_func sk_##name##_set_cmp_func(                \
+      STACK_OF(name) *sk, sk_##name##_cmp_func comp) {                         \
+    return (sk_##name##_cmp_func)OPENSSL_sk_set_cmp_func(                      \
+        (OPENSSL_STACK *)sk, (OPENSSL_sk_cmp_func)comp);                       \
+  }                                                                            \
+                                                                               \
+  OPENSSL_INLINE STACK_OF(name) *sk_##name##_deep_copy(                        \
+      const STACK_OF(name) *sk, sk_##name##_copy_func copy_func,               \
+      sk_##name##_free_func free_func) {                                       \
+    return (STACK_OF(name) *)OPENSSL_sk_deep_copy(                             \
+        (const OPENSSL_STACK *)sk, sk_##name##_call_copy_func,                 \
+        (OPENSSL_sk_copy_func)copy_func, sk_##name##_call_free_func,           \
+        (OPENSSL_sk_free_func)free_func);                                      \
+  }                                                                            \
+                                                                               \
   OPENSSL_MSVC_PRAGMA(warning(pop))
 
 
@@ -542,7 +566,9 @@
 // Stacks defined with |DEFINE_CONST_STACK_OF| are freed with |sk_free|.
 template <typename Stack>
 struct DeleterImpl<Stack, std::enable_if_t<StackTraits<Stack>::kIsConst>> {
-  static void Free(Stack *sk) { sk_free(reinterpret_cast<_STACK *>(sk)); }
+  static void Free(Stack *sk) {
+    OPENSSL_sk_free(reinterpret_cast<OPENSSL_STACK *>(sk));
+  }
 };
 
 // Stacks defined with |DEFINE_STACK_OF| are freed with |sk_pop_free| and the
@@ -553,11 +579,12 @@
     // sk_FOO_pop_free is defined by macros and bound by name, so we cannot
     // access it from C++ here.
     using Type = typename StackTraits<Stack>::Type;
-    sk_pop_free_ex(reinterpret_cast<_STACK *>(sk),
-                   [](OPENSSL_sk_free_func /* unused */, void *ptr) {
-                     DeleterImpl<Type>::Free(reinterpret_cast<Type *>(ptr));
-                   },
-                   nullptr);
+    OPENSSL_sk_pop_free_ex(
+        reinterpret_cast<OPENSSL_STACK *>(sk),
+        [](OPENSSL_sk_free_func /* unused */, void *ptr) {
+          DeleterImpl<Type>::Free(reinterpret_cast<Type *>(ptr));
+        },
+        nullptr);
   }
 };
 
@@ -578,7 +605,7 @@
 
   Type *operator*() const {
     return reinterpret_cast<Type *>(
-        sk_value(reinterpret_cast<const _STACK *>(sk_), idx_));
+        OPENSSL_sk_value(reinterpret_cast<const OPENSSL_STACK *>(sk_), idx_));
   }
 
   StackIteratorImpl &operator++(/* prefix */) {
@@ -609,10 +636,10 @@
 inline std::enable_if_t<!internal::StackTraits<Stack>::kIsConst, bool>
 PushToStack(Stack *sk,
             UniquePtr<typename internal::StackTraits<Stack>::Type> elem) {
-  if (!sk_push(reinterpret_cast<_STACK *>(sk), elem.get())) {
+  if (!OPENSSL_sk_push(reinterpret_cast<OPENSSL_STACK *>(sk), elem.get())) {
     return false;
   }
-  // sk_push takes ownership on success.
+  // OPENSSL_sk_push takes ownership on success.
   elem.release();
   return true;
 }
@@ -628,7 +655,7 @@
 template <typename Stack>
 inline bssl::internal::StackIterator<Stack> end(const Stack *sk) {
   return bssl::internal::StackIterator<Stack>(
-      sk, sk_num(reinterpret_cast<const _STACK *>(sk)));
+      sk, OPENSSL_sk_num(reinterpret_cast<const OPENSSL_STACK *>(sk)));
 }
 
 }  // extern C++