api changes, check README

CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.21)
 
 project(
     radhook
-    VERSION 1.0.0
+    VERSION 1.1.0
     DESCRIPTION "cross-platform function hooking library"
     LANGUAGES CXX
 )

README.md

@@ -5,13 +5,16 @@ MinHook and Dobby with a flat, C-style, handle-based API.
 
 ## Features
 - Inline hooking on x86-64 and AArch64
+- Vtable hooking via direct slot swapping, no trampoline required
 - Windows and Android support
 - Flat C API with opaque handles
 - Typed convenience overload of `RadHookCreate` for function pointers
 - Trampolines to call the original function from within a detour
 - Enable / disable / destroy individual hooks, or all hooks at once
+- Deferred enable/disable via a queue, applied atomically in one pass
 - Hook enumeration and introspection (target, detour, trampoline, enabled state)
 - Human-readable status strings
+- Runtime version query for ABI sanity checks
 - Builds as a static or shared library via CMake
 
 ## Requirements
@@ -28,10 +31,11 @@ cmake --build build
 ```
 
 Useful options:
-| Option                 | Default                | Description                                            |
+
-|------------------------|------------------------|--------------------------------------------------------|
+| Option                 | Default                | Description                                             |
-| `BUILD_SHARED_LIBS`    | `ON`                   | Build radhook as a shared library instead of static    |
+|------------------------|------------------------|---------------------------------------------------------|
-| `RADHOOK_BUILD_TESTS`  | `ON` when top-level    | Build the test suite                                   |
+| `BUILD_SHARED_LIBS`    | `ON`                   | Build radhook as a shared library instead of static     |
+| `RADHOOK_BUILD_TESTS`  | `ON` when top-level    | Build the test suite                                    |
 
 ### Build.ps1
 A helper PowerShell script is provided for common build targets:
@@ -44,6 +48,8 @@ A helper PowerShell script is provided for common build targets:
 ```
 
 ## Usage
+
+### Inline hooking
 ```cpp
 #include <radhook/radhook.h>
 
@@ -56,7 +62,7 @@ int main() {
     // create and install the hook
     RadHookResult result = RadHookCreate(TargetFunction, (void*)DetourFunction, &handle);
     if (result != RadHookResult::Success) {
-        // handle error
+        // handle error, RadHookResultToString(result) for a message
     }
 
     // call through the trampoline
@@ -72,22 +78,84 @@ int main() {
 }
 ```
 
+### Vtable hooking
+```cpp
+struct IFoo { 
+    virtual int Value() { return 7; } 
+    virtual ~IFoo() = default; 
+};
+
+int Detour(IFoo* self) { return 777; }
+
+IFoo obj;
+void** vtable = *reinterpret_cast<void***>(&obj);
+
+RadHookHandle handle = nullptr;
+RadHookVTableCreate(vtable, /*index=*/0, (void*)Detour, &handle);
+
+// no relocation is needed for vtable hooks
+using Fn = int(*)(IFoo*);
+Fn original = RadHookGetOriginalAs<Fn>(handle);
+original(&obj);
+
+RadHookDestroy(handle);
+```
+
+### Deferred apply
+Stage several enable/disable transitions and flip them together in one pass,
+instead of one hook at a time:
+
+```cpp
+RadHookQueueEnable(handleA);
+RadHookQueueDisable(handleB);
+
+// nothing has changed yet
+Foo();
+
+// then apply
+RadHookApplyQueued(); // both transitions land together
+```
+
+If a handle is queued more than once before `RadHookApplyQueued` runs, the
+most recent call wins.
+
 ## API overview
-| Function Name                                     | Description                                                |
+
-|---------------------------------------------------|------------------------------------------------------------|
+| Function Name                                       | Description                                                     |
-| `RadHookCreate`                                   | Create and install a hook, enabled by default              |
+|-----------------------------------------------------|-----------------------------------------------------------------|
-| `RadHookEnable`                                   | Enable an installed hook                                   |
+| `RadHookCreate`                                     | Create and install a hook, enabled by default                   |
-| `RadHookDisable`                                  | Disable an installed hook, restoring original bytes        |
+| `RadHookVTableCreate`                               | Create and install a hook on a vtable slot                      |
-| `RadHookDestroy`                                  | Disable, release, and invalidate a hook                    |
+| `RadHookEnable`                                     | Enable an installed hook                                        |
-| `RadHookEnableAll` / `RadHookDisableAll`          | Enable or disable every registered hook                    |
+| `RadHookDisable`                                    | Disable an installed hook, restoring original bytes             |
-| `RadHookGetCount`                                 | Number of currently registered hooks                       |
+| `RadHookDestroy`                                    | Disable, release, and invalidate a hook                         |
-| `RadHookGetHandles` / `RadHookEnumerate`          | Enumerate registered hook handles                          |
+| `RadHookEnableAll` / `RadHookDisableAll`            | Enable or disable every registered hook                         |
-| `RadHookIsValid`                                  | Check whether a handle refers to a registered hook         |
+| `RadHookQueueEnable` / `RadHookQueueDisable`        | Stage a hook's enable/disable state without applying it         |
-| `RadHookIsEnabled`                                | Check whether a hook is currently enabled                  |
+| `RadHookApplyQueued`                                | Apply every staged enable/disable transition at once            |
-| `RadHookGetTarget`                                | Get the hooked target function pointer                     |
+| `RadHookGetCount`                                   | Number of currently registered hooks                            |
-| `RadHookGetDetour`                                | Get the detour function pointer                            |
+| `RadHookGetHandles` / `RadHookEnumerate`            | Enumerate registered hook handles                               |
-| `RadHookGetOriginal` / `RadHookGetOriginalAs<T>`  | Get the trampoline to call the original implementation     |
+| `RadHookIsValid`                                    | Check whether a handle refers to a registered hook              |
-| `RadHookResultToString`                           | Human-readable name for a `RadHookResult`                  |
+| `RadHookIsEnabled`                                  | Check whether a hook is currently enabled                       |
+| `RadHookGetTarget`                                  | Get the hooked target function pointer                          |
+| `RadHookGetDetour`                                  | Get the detour function pointer                                 |
+| `RadHookGetOriginal` / `RadHookGetOriginalAs<T>`    | Get the trampoline to call the original implementation          |
+| `RadHookResultToString`                             | Human-readable name for a `RadHookResult`                       |
+| `RadHookGetVersion`                                 | Query the library's major/minor/patch version                   |
+
+All fallible operations return a `RadHookResult`, including granular error
+codes such as `TrampolineTooFar`, `DisassemblyFailed`, and
+`MemoryProtectFailed`.
+
+## Testing
+Tests are built with CTest and cover creation, enable/disable and lifecycle
+transitions, trampoline behavior, vtable hooking, queued apply, invalid
+input handling, failure cases, memory integrity, and stress/churn
+scenarios.
+
+```sh
+cmake -S . -B build -DRADHOOK_BUILD_TESTS=ON
+cmake --build build
+ctest --test-dir build --output-on-failure
+```
 
 ## License
 Licensed under the GNU Lesser General Public License v3 (LGPLv3). See [LICENSE](LICENSE) for details.

include/radhook/api.h

@@ -10,6 +10,24 @@
 # define RADHOOK_API
 #endif // RADHOOK_API
 
+// versioning
+#define RADHOOK_VERSION_MAJOR 1
+#define RADHOOK_VERSION_MINOR 1
+#define RADHOOK_VERSION_PATCH 0
+
+#if _MSC_VER
+# include <sal.h> // for source code annotations
+#else
+# define _In_
+# define _In_opt_
+# define _Out_
+# define _Out_opt_
+# define _Outptr_
+# define _Ret_z_
+# define _Success_(expr)
+# define _Out_writes_to_(size, count)
+#endif
+
 enum class RadHookResult : int {
     Success = 0,
     AlreadyInstalled,
@@ -26,6 +44,7 @@ enum class RadHookResult : int {
     Unknown,
 };
 
+_Ret_z_
 /**
  * @brief Creates a human readable name for a status code.
  *
@@ -36,11 +55,12 @@ RADHOOK_API
 const char*
 RadHookResultToString(
     RadHookResult result
-);
+    );
 
 struct RadHookOpaque;
 using RadHookHandle = RadHookOpaque*;
 
+_Success_(return == RadHookResult::Success)
 /**
  * @brief Creates and installs a hook.
  *
@@ -57,18 +77,19 @@ using RadHookHandle = RadHookOpaque*;
 RADHOOK_API
 RadHookResult
 RadHookCreate(
-    void* target, 
+    _In_ void* target,
-    void* detour, 
+    _In_ void* detour,
-    RadHookHandle* outHandle
+    _Out_ RadHookHandle* outHandle
-);
+    );
 
+_Success_(return == RadHookResult::Success)
 /**
  * @brief Creates and installs a hook from a function pointer.
  *
  * Convenience overload that accepts a typed function pointer for the target.
  *
  * @tparam TargetFn Target function pointer type.
- * @param target Function to hook.
+ * @param target Target function to hook.
  * @param detour Replacement function.
  * @param outHandle Receives the created hook handle on success.
  *
@@ -79,9 +100,10 @@ requires std::is_function_v<std::remove_pointer_t<TargetFn>>
 RadHookResult
 RadHookCreate(
     TargetFn target,
-    void* detour,
+    _In_ void* detour,
-    RadHookHandle* outHandle
+    _Out_ RadHookHandle* outHandle
-) {
+    ) 
+{
     return RadHookCreate(
         reinterpret_cast<void*>(target),
         detour,
@@ -102,8 +124,8 @@ RadHookCreate(
 RADHOOK_API
 RadHookResult
 RadHookEnable(
-    RadHookHandle handle
+    _In_ RadHookHandle handle
-);
+    );
 
 /**
  * @brief Disables an installed hook.
@@ -118,8 +140,8 @@ RadHookEnable(
 RADHOOK_API
 RadHookResult
 RadHookDisable(
-    RadHookHandle handle
+    _In_ RadHookHandle handle
-);
+    );
 
 /**
  * @brief Destroys a hook.
@@ -134,8 +156,8 @@ RadHookDisable(
 RADHOOK_API
 RadHookResult
 RadHookDestroy(
-    RadHookHandle handle
+    _In_ RadHookHandle handle
-);
+    );
 
 /**
  * @brief Enables every registered hook.
@@ -170,6 +192,7 @@ RADHOOK_API
 size_t
 RadHookGetCount();
 
+_Out_writes_to_(maxCount, return)
 /**
  * @brief Retrieves registered hook handles.
  *
@@ -184,9 +207,9 @@ RadHookGetCount();
 RADHOOK_API
 size_t
 RadHookGetHandles(
-    RadHookHandle* outHandles, 
+    _Out_ RadHookHandle* outHandles,
-    size_t maxCount
+    _In_ size_t maxCount
-);
+    );
 
 /**
  * @brief Checks whether a hook handle is valid.
@@ -198,8 +221,8 @@ RadHookGetHandles(
 RADHOOK_API
 bool
 RadHookIsValid(
-    RadHookHandle handle
+    _In_ RadHookHandle handle
-);
+    );
 
 /**
  * @brief Checks whether a hook is currently enabled.
@@ -211,8 +234,8 @@ RadHookIsValid(
 RADHOOK_API
 bool
 RadHookIsEnabled(
-    RadHookHandle handle
+    _In_ RadHookHandle handle
-);
+    );
 
 /**
  * @brief Returns the hooked target function.
@@ -225,8 +248,8 @@ RadHookIsEnabled(
 RADHOOK_API
 void*
 RadHookGetTarget(
-    RadHookHandle handle
+    _In_ RadHookHandle handle
-);
+    );
 
 /**
  * @brief Returns the detour function.
@@ -239,8 +262,8 @@ RadHookGetTarget(
 RADHOOK_API
 void*
 RadHookGetDetour(
-    RadHookHandle handle
+    _In_ RadHookHandle handle
-);
+    );
 
 /**
  * @brief Returns the trampoline containing the relocated original code.
@@ -255,8 +278,8 @@ RadHookGetDetour(
 RADHOOK_API
 void*
 RadHookGetOriginal(
-    RadHookHandle handle
+    _In_ RadHookHandle handle
-);
+    );
 
 /**
  * @brief Returns the trampoline cast to a function pointer type.
@@ -269,30 +292,123 @@ RadHookGetOriginal(
 template <typename FnPtr>
 FnPtr
 RadHookGetOriginalAs(
-    RadHookHandle handle
+    _In_ RadHookHandle handle
-) {
+    ) 
+{
     return reinterpret_cast<FnPtr>(RadHookGetOriginal(handle));
 }
 
- /**
+_Out_writes_to_(maxCount, return)
-  * @brief Enumerates currently registered hooks.
+/**
-  *
+ * @brief Enumerates currently registered hooks.
-  * Copies up to @p maxCount active hook handles into @p out.
+ *
-  * Handles are written in no particular order.
+ * Copies up to @p maxCount active hook handles into @p out.
-  *
+ * Handles are written in no particular order.
-  * This function only returns hooks that are currently registered
+ *
-  * and not destroyed.
+ * This function only returns hooks that are currently registered
-  *
+ * and not destroyed.
-  * @param out Destination buffer for hook handles.
+ *
-  * @param maxCount Maximum number of handles to copy.
+ * @param out Destination buffer for hook handles.
-  *
+ * @param maxCount Maximum number of handles to copy.
-  * @return Number of hook handles written into @p out.
+ *
-  */
+ * @return Number of hook handles written into @p out.
+ */
 RADHOOK_API
 size_t
 RadHookEnumerate(
-    RadHookHandle* out,
+    _Out_ RadHookHandle* out,
-    size_t maxCount
+    _In_ size_t maxCount
-);
+    );
+
+/**
+ * @brief Returns the library version.
+ *
+ * Any of the output parameters may be nullptr if that component is not
+ * needed. Useful for verifying ABI compatibility when radhook is loaded
+ * as a shared library independently of the consuming module.
+ *
+ * @param outMajor Receives the major version, or nullptr.
+ * @param outMinor Receives the minor version, or nullptr.
+ * @param outPatch Receives the patch version, or nullptr.
+ */
+RADHOOK_API
+void
+RadHookGetVersion(
+    _Out_opt_ int* outMajor,
+    _Out_opt_ int* outMinor,
+    _Out_opt_ int* outPatch
+    );
+
+_Success_(return == RadHookResult::Success)
+/**
+ * @brief Creates and installs a hook on a vtable slot.
+ *
+ * @param vtable Pointer to the base of the vtable.
+ * @param index Index of the slot to hook.
+ * @param detour Replacement function.
+ * @param outHandle Receives the created hook handle on success. Set to nullptr on failure.
+ *
+ * @return InvalidTarget if @p vtable is nullptr or the slot
+ * at @p index is empty; otherwise the result of the operation.
+ */
+RADHOOK_API
+RadHookResult
+RadHookVTableCreate(
+    _In_ void** vtable,
+    _In_ size_t index,
+    _In_ void* detour,
+    _Out_ RadHookHandle* outHandle
+    );
+
+/**
+ * @brief Queues a hook to be enabled on the next RadHookApplyQueued call.
+ *
+ * Does not modify the hook itself. If the same handle is queued for both
+ * enable and disable before RadHookApplyQueued runs, the most recent call
+ * wins.
+ *
+ * @param handle Hook handle.
+ *
+ * @return RadHookResult::InvalidHandle if the handle is not registered;
+ * otherwise RadHookResult::Success.
+ */
+RADHOOK_API
+RadHookResult
+RadHookQueueEnable(
+    _In_ RadHookHandle handle
+    );
+
+/**
+ * @brief Queues a hook to be disabled on the next RadHookApplyQueued call.
+ *
+ * Does not modify the hook itself. If the same handle is queued for both
+ * enable and disable before RadHookApplyQueued runs, the most recent call
+ * wins.
+ *
+ * @param handle Hook handle.
+ *
+ * @return RadHookResult::InvalidHandle if the handle is not registered;
+ * otherwise RadHookResult::Success.
+ */
+RADHOOK_API
+RadHookResult
+RadHookQueueDisable(
+    _In_ RadHookHandle handle
+    );
+
+/**
+ * @brief Applies all queued enable/disable operations.
+ *
+ * Every hook with a pending queued action has that action applied and its
+ * queue cleared, regardless of individual outcomes. Hooks with no queued
+ * action are left untouched.
+ *
+ * @return The result of the first queued operation that did not succeed
+ * (ignoring RadHookResult::AlreadyEnabled / RadHookResult::AlreadyDisabled),
+ * or RadHookResult::Success if all applied cleanly.
+ */
+RADHOOK_API
+RadHookResult
+RadHookApplyQueued();
 
 #endif // __LIBRADHOOK_API_H__

src/radhook.cpp

@@ -18,6 +18,8 @@
 # include <unistd.h>
 #endif
 
+// stupid macros messing up compilation because it conflicts with
+// std::min and std::max
 #undef min
 #undef max
 
@@ -40,6 +42,17 @@ const char* RadHookResultToString(RadHookResult result) {
     }
 }
 
+enum class RadHookKind : int {
+    Inline,
+    VTable,
+};
+
+enum class RadHookQueuedAction : int {
+    None,
+    Enable,
+    Disable,
+};
+
 // hook record
 struct RadHookOpaque {
     void* target = nullptr;
@@ -56,6 +69,12 @@ struct RadHookOpaque {
     size_t stubLength = 0;
 
     bool enabled = false;
+
+    RadHookKind kind = RadHookKind::Inline;
+    void** vtableSlot = nullptr;
+    void* vtableOriginalEntry = nullptr;
+
+    RadHookQueuedAction queuedAction = RadHookQueuedAction::None;
 };
 
 namespace {
@@ -121,8 +140,10 @@ void* AllocExecNear(void* target, size_t size) {
         if (mbi.State == MEM_FREE) {
             uintptr_t allocBase = (regionBase + pageSize - 1) & ~(pageSize - 1);
             if (allocBase + size <= regionBase + mbi.RegionSize && allocBase + size <= maxAddr) {
-                void* p = VirtualAlloc(reinterpret_cast<LPVOID>(allocBase), size,
+                void* p = VirtualAlloc(
-                                        MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
+                    reinterpret_cast<LPVOID>(allocBase), size,
+                    MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE
+                );
                 if (p) return p;
             }
         }
@@ -598,6 +619,21 @@ RadHookResult InstallHook(RadHookOpaque* h, void* target, void* detour) {
 }
 
 RadHookResult EnableHookInternal(RadHookOpaque* h) {
+    if (h->kind == RadHookKind::VTable) {
+        if (!h->vtableSlot) return RadHookResult::NotInstalled;
+        if (h->enabled) return RadHookResult::AlreadyEnabled;
+
+        unsigned long oldProtect = 0;
+        if (!MakeWritableExecutable(h->vtableSlot, sizeof(void*), &oldProtect)) {
+            return RadHookResult::MemoryProtectFailed;
+        }
+        *h->vtableSlot = h->detour;
+        RestoreProtection(h->vtableSlot, sizeof(void*), oldProtect);
+
+        h->enabled = true;
+        return RadHookResult::Success;
+    }
+
     if (!h->target) return RadHookResult::NotInstalled;
     if (h->enabled) return RadHookResult::AlreadyEnabled;
 
@@ -614,6 +650,21 @@ RadHookResult EnableHookInternal(RadHookOpaque* h) {
 }
 
 RadHookResult DisableHookInternal(RadHookOpaque* h) {
+    if (h->kind == RadHookKind::VTable) {
+        if (!h->vtableSlot) return RadHookResult::NotInstalled;
+        if (!h->enabled) return RadHookResult::AlreadyDisabled;
+
+        unsigned long oldProtect = 0;
+        if (!MakeWritableExecutable(h->vtableSlot, sizeof(void*), &oldProtect)) {
+            return RadHookResult::MemoryProtectFailed;
+        }
+        *h->vtableSlot = h->vtableOriginalEntry;
+        RestoreProtection(h->vtableSlot, sizeof(void*), oldProtect);
+
+        h->enabled = false;
+        return RadHookResult::Success;
+    }
+
     if (!h->target) return RadHookResult::NotInstalled;
     if (!h->enabled) return RadHookResult::AlreadyDisabled;
 
@@ -759,3 +810,73 @@ size_t RadHookEnumerate(RadHookHandle* out, size_t maxCount) {
 
     return written;
 }
+
+void RadHookGetVersion(int* outMajor, int* outMinor, int* outPatch) {
+    if (outMajor) *outMajor = RADHOOK_VERSION_MAJOR;
+    if (outMinor) *outMinor = RADHOOK_VERSION_MINOR;
+    if (outPatch) *outPatch = RADHOOK_VERSION_PATCH;
+}
+
+RadHookResult RadHookVTableCreate(void** vtable, size_t index, void* detour, RadHookHandle* outHandle) {
+    if (outHandle) *outHandle = nullptr;
+    if (!vtable) return RadHookResult::InvalidTarget;
+    if (!detour) return RadHookResult::InvalidDetour;
+
+    void** slot = vtable + index;
+    void* original = *slot;
+    if (!original) return RadHookResult::InvalidTarget;
+
+    auto record = std::make_unique<RadHookOpaque>();
+    record->kind = RadHookKind::VTable;
+    record->vtableSlot = slot;
+    record->vtableOriginalEntry = original;
+    record->target = original;
+    record->detour = detour;
+    record->trampoline = original;
+
+    RadHookResult result = EnableHookInternal(record.get());
+    if (result != RadHookResult::Success) {
+        return result;
+    }
+
+    std::lock_guard<std::mutex> lock(g_mutex);
+    RadHookOpaque* raw = record.get();
+    g_hooks.push_back(std::move(record));
+    if (outHandle) *outHandle = raw;
+    return RadHookResult::Success;
+}
+
+RadHookResult RadHookQueueEnable(RadHookHandle handle) {
+    std::lock_guard<std::mutex> lock(g_mutex);
+    if (!IsRegisteredLocked(handle)) return RadHookResult::InvalidHandle;
+    handle->queuedAction = RadHookQueuedAction::Enable;
+    return RadHookResult::Success;
+}
+
+RadHookResult RadHookQueueDisable(RadHookHandle handle) {
+    std::lock_guard<std::mutex> lock(g_mutex);
+    if (!IsRegisteredLocked(handle)) return RadHookResult::InvalidHandle;
+    handle->queuedAction = RadHookQueuedAction::Disable;
+    return RadHookResult::Success;
+}
+
+RadHookResult RadHookApplyQueued() {
+    std::lock_guard<std::mutex> lock(g_mutex);
+    RadHookResult last = RadHookResult::Success;
+    for (auto& h : g_hooks) {
+        RadHookQueuedAction action = h->queuedAction;
+        if (action == RadHookQueuedAction::None) continue;
+        h->queuedAction = RadHookQueuedAction::None;
+
+        RadHookResult r = (action == RadHookQueuedAction::Enable)
+            ? EnableHookInternal(h.get())
+            : DisableHookInternal(h.get());
+
+        if (r != RadHookResult::Success &&
+            r != RadHookResult::AlreadyEnabled &&
+            r != RadHookResult::AlreadyDisabled) {
+            last = r;
+        }
+    }
+    return last;
+}

tests/test_queue.cpp

@@ -0,0 +1,68 @@
+#include <cassert>
+#include "radhook/radhook.h"
+
+static int fnA() { return 1; }
+static int detourA() { return 100; }
+
+static int fnB() { return 2; }
+static int detourB() { return 200; }
+
+static int fnC() { return 3; }
+static int detourC() { return 300; }
+
+int main() {
+    RadHookHandle hA = nullptr;
+    RadHookHandle hB = nullptr;
+
+    assert(RadHookCreate((void*)fnA, (void*)detourA, &hA) == RadHookResult::Success);
+    assert(RadHookCreate((void*)fnB, (void*)detourB, &hB) == RadHookResult::Success);
+
+    // start both from a known, disabled state
+    assert(RadHookDisable(hA) == RadHookResult::Success);
+    assert(RadHookDisable(hB) == RadHookResult::Success);
+    assert(fnA() == 1);
+    assert(fnB() == 2);
+
+    // queueing must not apply immediately
+    assert(RadHookQueueEnable(hA) == RadHookResult::Success);
+    assert(RadHookQueueEnable(hB) == RadHookResult::Success);
+    assert(!RadHookIsEnabled(hA));
+    assert(!RadHookIsEnabled(hB));
+    assert(fnA() == 1);
+    assert(fnB() == 2);
+
+    // apply enables both together
+    assert(RadHookApplyQueued() == RadHookResult::Success);
+    assert(RadHookIsEnabled(hA));
+    assert(RadHookIsEnabled(hB));
+    assert(fnA() == 100);
+    assert(fnB() == 200);
+
+    // last queued action before apply wins
+    assert(RadHookQueueDisable(hA) == RadHookResult::Success);
+    assert(RadHookQueueEnable(hA) == RadHookResult::Success);
+    assert(RadHookApplyQueued() == RadHookResult::Success);
+    assert(RadHookIsEnabled(hA));
+
+    // an apply with nothing queued is a no-op
+    assert(RadHookApplyQueued() == RadHookResult::Success);
+
+    // queueing a redundant transition (already enabled) still applies cleanly
+    assert(RadHookQueueEnable(hA) == RadHookResult::Success);
+    assert(RadHookApplyQueued() == RadHookResult::Success);
+    assert(RadHookIsEnabled(hA));
+
+    // invalid handles
+    assert(RadHookQueueEnable(nullptr) == RadHookResult::InvalidHandle);
+    assert(RadHookQueueDisable(nullptr) == RadHookResult::InvalidHandle);
+
+    // a destroyed hook can no longer be queued
+    RadHookHandle hC = nullptr;
+    assert(RadHookCreate((void*)fnC, (void*)detourC, &hC) == RadHookResult::Success);
+    RadHookDestroy(hC);
+    assert(RadHookQueueEnable(hC) == RadHookResult::InvalidHandle);
+
+    RadHookDestroy(hA);
+    RadHookDestroy(hB);
+    return 0;
+}

tests/test_version.cpp

@@ -0,0 +1,20 @@
+#include <cassert>
+#include "radhook/radhook.h"
+
+int main() {
+    int major = -1, minor = -1, patch = -1;
+    RadHookGetVersion(&major, &minor, &patch);
+
+    assert(major == RADHOOK_VERSION_MAJOR);
+    assert(minor == RADHOOK_VERSION_MINOR);
+    assert(patch == RADHOOK_VERSION_PATCH);
+
+    // individual out params may be omitted independently
+    int onlyMajor = -1;
+    RadHookGetVersion(&onlyMajor, nullptr, nullptr);
+    assert(onlyMajor == RADHOOK_VERSION_MAJOR);
+
+    // must not crash
+    RadHookGetVersion(nullptr, nullptr, nullptr);
+    return 0;
+}

tests/test_vtable.cpp

@@ -0,0 +1,68 @@
+#include <cassert>
+#include "radhook/radhook.h"
+
+struct IFoo {
+    virtual int Value() { return 7; }
+    virtual ~IFoo() = default;
+};
+
+static int DetourValue(IFoo* /*self*/) { return 777; }
+
+using Fn = int(*)(IFoo*);
+
+int main() {
+    IFoo obj;
+    void** vtable = *reinterpret_cast<void***>(&obj);
+
+    RadHookHandle h = nullptr;
+    assert(RadHookVTableCreate(vtable, 0, (void*)DetourValue, &h) == RadHookResult::Success);
+    assert(RadHookIsValid(h));
+    assert(RadHookIsEnabled(h));
+
+    // handle is created enabled, so the swap must already be visible
+    assert(obj.Value() == 777);
+    assert(reinterpret_cast<Fn>(vtable[0])(&obj) == 777);
+
+    void* originalEntry = RadHookGetTarget(h);
+    assert(originalEntry != nullptr);
+    assert(RadHookGetDetour(h) == reinterpret_cast<void*>(DetourValue));
+
+    // disable restores the original vtable entry
+    assert(RadHookDisable(h) == RadHookResult::Success);
+    assert(!RadHookIsEnabled(h));
+    assert(obj.Value() == 7);
+    assert(vtable[0] == originalEntry);
+
+    // re-enable re-applies the swap
+    assert(RadHookEnable(h) == RadHookResult::Success);
+    assert(obj.Value() == 777);
+
+    // no relocation is needed for vtable hooks -- the trampoline is the
+    // original entry itself and can be called directly while the hook is live
+    auto original = RadHookGetOriginalAs<Fn>(h);
+    assert(reinterpret_cast<void*>(original) == originalEntry);
+    assert(original(&obj) == 7);
+
+    RadHookDestroy(h);
+    assert(!RadHookIsValid(h));
+    assert(obj.Value() == 7);
+
+    // queueing works uniformly across inline and vtable hook kinds
+    RadHookHandle h2 = nullptr;
+    assert(RadHookVTableCreate(vtable, 0, (void*)DetourValue, &h2) == RadHookResult::Success);
+    assert(RadHookQueueDisable(h2) == RadHookResult::Success);
+    assert(RadHookIsEnabled(h2)); // not applied yet
+    assert(RadHookApplyQueued() == RadHookResult::Success);
+    assert(!RadHookIsEnabled(h2));
+    assert(obj.Value() == 7);
+    RadHookDestroy(h2);
+
+    // invalid inputs
+    RadHookHandle bad = nullptr;
+    assert(RadHookVTableCreate(nullptr, 0, (void*)DetourValue, &bad) == RadHookResult::InvalidTarget);
+    assert(bad == nullptr);
+    assert(RadHookVTableCreate(vtable, 0, nullptr, &bad) == RadHookResult::InvalidDetour);
+    assert(bad == nullptr);
+
+    return 0;
+}