diff --git a/libutils/include/utils/CallStack.h b/libutils/include/utils/CallStack.h
index 54d559b..0239b68 100644
--- a/libutils/include/utils/CallStack.h
+++ b/libutils/include/utils/CallStack.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef ANDROID_CALLSTACK_H
-#define ANDROID_CALLSTACK_H
+#pragma once
 
 #include <memory>
 
@@ -27,14 +26,14 @@
 #include <sys/types.h>
 
 #if !defined(__APPLE__) && !defined(_WIN32)
-# define WEAKS_AVAILABLE 1
+# define CALLSTACK_WEAKS_AVAILABLE 1
 #endif
 #ifndef CALLSTACK_WEAK
-# ifdef WEAKS_AVAILABLE
+# ifdef CALLSTACK_WEAKS_AVAILABLE
 #   define CALLSTACK_WEAK __attribute__((weak))
-# else // !WEAKS_AVAILABLE
+# else // !CALLSTACK_WEAKS_AVAILABLE
 #   define CALLSTACK_WEAK
-# endif // !WEAKS_AVAILABLE
+# endif // !CALLSTACK_WEAKS_AVAILABLE
 #endif // CALLSTACK_WEAK predefined
 
 #ifndef CALLSTACK_ALWAYS_INLINE
@@ -91,7 +90,7 @@
     //
     // DO NOT USE THESE. They will disappear.
     struct StackDeleter {
-#ifdef WEAKS_AVAILABLE
+#ifdef CALLSTACK_WEAKS_AVAILABLE
         void operator()(CallStack* stack) {
             deleteStack(stack);
         }
@@ -103,7 +102,7 @@
     typedef std::unique_ptr<CallStack, StackDeleter> CallStackUPtr;
 
     // Return current call stack if possible, nullptr otherwise.
-#ifdef WEAKS_AVAILABLE
+#ifdef CALLSTACK_WEAKS_AVAILABLE
     static CallStackUPtr CALLSTACK_ALWAYS_INLINE getCurrent(int32_t ignoreDepth = 1) {
         if (reinterpret_cast<uintptr_t>(getCurrentInternal) == 0) {
             ALOGW("CallStack::getCurrentInternal not linked, returning null");
@@ -112,13 +111,13 @@
             return getCurrentInternal(ignoreDepth);
         }
     }
-#else // !WEAKS_AVAILABLE
+#else // !CALLSTACK_WEAKS_AVAILABLE
     static CallStackUPtr CALLSTACK_ALWAYS_INLINE getCurrent(int32_t = 1) {
         return CallStackUPtr(nullptr);
     }
-#endif // !WEAKS_AVAILABLE
+#endif // !CALLSTACK_WEAKS_AVAILABLE
 
-#ifdef WEAKS_AVAILABLE
+#ifdef CALLSTACK_WEAKS_AVAILABLE
     static void CALLSTACK_ALWAYS_INLINE logStack(const char* logtag,
                                                  CallStack* stack = getCurrent().get(),
                                                  android_LogPriority priority = ANDROID_LOG_DEBUG) {
@@ -135,9 +134,9 @@
                                                  android_LogPriority = ANDROID_LOG_DEBUG) {
         ALOG(LOG_WARN, logtag, "CallStack::logStackInternal not linked");
     }
-#endif // !WEAKS_AVAILABLE
+#endif // !CALLSTACK_WEAKS_AVAILABLE
 
-#ifdef WEAKS_AVAILABLE
+#ifdef CALLSTACK_WEAKS_AVAILABLE
     static String8 CALLSTACK_ALWAYS_INLINE
     stackToString(const char* prefix = nullptr, const CallStack* stack = getCurrent().get()) {
         if (reinterpret_cast<uintptr_t>(stackToStringInternal) != 0 && stack != nullptr) {
@@ -146,15 +145,15 @@
             return String8::format("%s<CallStack package not linked>", (prefix ? prefix : ""));
         }
     }
-#else // !WEAKS_AVAILABLE
+#else // !CALLSTACK_WEAKS_AVAILABLE
     static String8 CALLSTACK_ALWAYS_INLINE stackToString(const char* prefix = nullptr,
                                                          const CallStack* = getCurrent().get()) {
         return String8::format("%s<CallStack package not linked>", (prefix ? prefix : ""));
     }
-#endif // !WEAKS_AVAILABLE
+#endif // !CALLSTACK_WEAKS_AVAILABLE
 
   private:
-#ifdef WEAKS_AVAILABLE
+#ifdef CALLSTACK_WEAKS_AVAILABLE
     static CallStackUPtr CALLSTACK_WEAK getCurrentInternal(int32_t ignoreDepth);
     static void CALLSTACK_WEAK logStackInternal(const char* logtag, const CallStack* stack,
                                                 android_LogPriority priority);
@@ -162,13 +161,13 @@
     // The deleter is only invoked on non-null pointers. Hence it will never be
     // invoked if CallStack is not linked.
     static void CALLSTACK_WEAK deleteStack(CallStack* stack);
-#endif // WEAKS_AVAILABLE
+#endif // CALLSTACK_WEAKS_AVAILABLE
 
     Vector<String8> mFrameLines;
 };
 
 }  // namespace android
 
+#undef CALLSTACK_WEAKS_AVAILABLE
+#undef CALLSTACK_WEAK
 #undef CALLSTACK_ALWAYS_INLINE
-
-#endif // ANDROID_CALLSTACK_H