diff --git a/gatekeeperd/IGateKeeperService.cpp b/gatekeeperd/IGateKeeperService.cpp
index 1c339f4..43d5708 100644
--- a/gatekeeperd/IGateKeeperService.cpp
+++ b/gatekeeperd/IGateKeeperService.cpp
@@ -70,7 +70,7 @@
             } else {
                 reply->writeInt32(GATEKEEPER_RESPONSE_ERROR);
             }
-            return NO_ERROR;
+            return OK;
         }
         case VERIFY: {
             CHECK_INTERFACE(IGateKeeperService, data, reply);
@@ -102,7 +102,7 @@
             } else {
                 reply->writeInt32(GATEKEEPER_RESPONSE_ERROR);
             }
-            return NO_ERROR;
+            return OK;
         }
         case VERIFY_CHALLENGE: {
             CHECK_INTERFACE(IGateKeeperService, data, reply);
@@ -141,7 +141,7 @@
             } else {
                 reply->writeInt32(GATEKEEPER_RESPONSE_ERROR);
             }
-            return NO_ERROR;
+            return OK;
         }
         case GET_SECURE_USER_ID: {
             CHECK_INTERFACE(IGateKeeperService, data, reply);
@@ -149,20 +149,20 @@
             uint64_t sid = getSecureUserId(uid);
             reply->writeNoException();
             reply->writeInt64(sid);
-            return NO_ERROR;
+            return OK;
         }
         case CLEAR_SECURE_USER_ID: {
             CHECK_INTERFACE(IGateKeeperService, data, reply);
             uint32_t uid = data.readInt32();
             clearSecureUserId(uid);
             reply->writeNoException();
-            return NO_ERROR;
+            return OK;
         }
         case REPORT_DEVICE_SETUP_COMPLETE: {
             CHECK_INTERFACE(IGateKeeperService, data, reply);
             reportDeviceSetupComplete();
             reply->writeNoException();
-            return NO_ERROR;
+            return OK;
         }
         default:
             return BBinder::onTransact(code, data, reply, flags);
diff --git a/gatekeeperd/gatekeeperd.cpp b/gatekeeperd/gatekeeperd.cpp
index 5f3ce36..f2818f3 100644
--- a/gatekeeperd/gatekeeperd.cpp
+++ b/gatekeeperd/gatekeeperd.cpp
@@ -386,7 +386,7 @@
             write(fd, result, strlen(result) + 1);
         }
 
-        return NO_ERROR;
+        return OK;
     }
 
 private:
diff --git a/healthd/BatteryMonitor.cpp b/healthd/BatteryMonitor.cpp
index 80c5afe..2a5667c 100644
--- a/healthd/BatteryMonitor.cpp
+++ b/healthd/BatteryMonitor.cpp
@@ -357,7 +357,7 @@
         if (!mHealthdConfig->batteryChargeCounterPath.isEmpty()) {
             val->valueInt64 =
                 getIntField(mHealthdConfig->batteryChargeCounterPath);
-            ret = NO_ERROR;
+            ret = OK;
         } else {
             ret = NAME_NOT_FOUND;
         }
@@ -367,7 +367,7 @@
         if (!mHealthdConfig->batteryCurrentNowPath.isEmpty()) {
             val->valueInt64 =
                 getIntField(mHealthdConfig->batteryCurrentNowPath);
-            ret = NO_ERROR;
+            ret = OK;
         } else {
             ret = NAME_NOT_FOUND;
         }
@@ -377,7 +377,7 @@
         if (!mHealthdConfig->batteryCurrentAvgPath.isEmpty()) {
             val->valueInt64 =
                 getIntField(mHealthdConfig->batteryCurrentAvgPath);
-            ret = NO_ERROR;
+            ret = OK;
         } else {
             ret = NAME_NOT_FOUND;
         }
@@ -387,7 +387,7 @@
         if (!mHealthdConfig->batteryCapacityPath.isEmpty()) {
             val->valueInt64 =
                 getIntField(mHealthdConfig->batteryCapacityPath);
-            ret = NO_ERROR;
+            ret = OK;
         } else {
             ret = NAME_NOT_FOUND;
         }
@@ -403,7 +403,7 @@
 
     case BATTERY_PROP_BATTERY_STATUS:
         val->valueInt64 = getChargeStatus();
-        ret = NO_ERROR;
+        ret = OK;
         break;
 
     default:
diff --git a/libpixelflinger/codeflinger/ARMAssembler.cpp b/libpixelflinger/codeflinger/ARMAssembler.cpp
index ac009a9..f47b6e4 100644
--- a/libpixelflinger/codeflinger/ARMAssembler.cpp
+++ b/libpixelflinger/codeflinger/ARMAssembler.cpp
@@ -171,7 +171,7 @@
     }
 
     mAssembly->resize( int(pc()-base())*4 );
-    
+
     // the instruction cache is flushed by CodeCache
     const int64_t duration = ggl_system_time() - mDuration;
     const char * const format = "generated %s (%d ins) at [%p:%p] in %lld ns\n";
@@ -183,8 +183,8 @@
         printf(format, name, int(pc()-base()), base(), pc(), duration);
         disassemble(name);
     }
-    
-    return NO_ERROR;
+
+    return OK;
 }
 
 uint32_t* ARMAssembler::pcForLabel(const char* label)
@@ -213,14 +213,14 @@
 // multiply...
 void ARMAssembler::MLA(int cc, int s,
         int Rd, int Rm, int Rs, int Rn) {
-    if (Rd == Rm) { int t = Rm; Rm=Rs; Rs=t; } 
+    if (Rd == Rm) { int t = Rm; Rm=Rs; Rs=t; }
     LOG_FATAL_IF(Rd==Rm, "MLA(r%u,r%u,r%u,r%u)", Rd,Rm,Rs,Rn);
     *mPC++ =    (cc<<28) | (1<<21) | (s<<20) |
                 (Rd<<16) | (Rn<<12) | (Rs<<8) | 0x90 | Rm;
 }
 void ARMAssembler::MUL(int cc, int s,
         int Rd, int Rm, int Rs) {
-    if (Rd == Rm) { int t = Rm; Rm=Rs; Rs=t; } 
+    if (Rd == Rm) { int t = Rm; Rm=Rs; Rs=t; }
     LOG_FATAL_IF(Rd==Rm, "MUL(r%u,r%u,r%u)", Rd,Rm,Rs);
     *mPC++ = (cc<<28) | (s<<20) | (Rd<<16) | (Rs<<8) | 0x90 | Rm;
 }
@@ -577,4 +577,3 @@
 }
 
 }; // namespace android
-
diff --git a/libpixelflinger/codeflinger/Arm64Assembler.cpp b/libpixelflinger/codeflinger/Arm64Assembler.cpp
index aebc129..8926776 100644
--- a/libpixelflinger/codeflinger/Arm64Assembler.cpp
+++ b/libpixelflinger/codeflinger/Arm64Assembler.cpp
@@ -325,7 +325,7 @@
         printf(format, name, int(pc()-base()), base(), pc(), duration);
         disassemble(name);
     }
-    return NO_ERROR;
+    return OK;
 }
 
 uint32_t* ArmToArm64Assembler::pcForLabel(const char* label)
@@ -1238,4 +1238,3 @@
 }
 
 }; // namespace android
-
diff --git a/libpixelflinger/codeflinger/MIPSAssembler.cpp b/libpixelflinger/codeflinger/MIPSAssembler.cpp
index 039a725..7de8cc1 100644
--- a/libpixelflinger/codeflinger/MIPSAssembler.cpp
+++ b/libpixelflinger/codeflinger/MIPSAssembler.cpp
@@ -1421,7 +1421,7 @@
         disassemble(name);
     }
 
-    return NO_ERROR;
+    return OK;
 }
 
 uint32_t* MIPSAssembler::pcForLabel(const char* label)
@@ -1953,5 +1953,3 @@
 
 
 }; // namespace android:
-
-
diff --git a/libsystem/include/system/camera.h b/libsystem/include/system/camera.h
index 7d79673..2ca90c3 100644
--- a/libsystem/include/system/camera.h
+++ b/libsystem/include/system/camera.h
@@ -158,8 +158,8 @@
      *
      * When any camera method returns error, the client can use ping command
      * to see if the camera has been taken away by other clients. If the result
-     * is NO_ERROR, it means the camera hardware is not released. If the result
-     * is not NO_ERROR, the camera has been released and the existing client
+     * is OK, it means the camera hardware is not released. If the result
+     * is not OK, the camera has been released and the existing client
      * can silently finish itself or show a dialog.
      */
     CAMERA_CMD_PING = 9,
diff --git a/libutils/PropertyMap.cpp b/libutils/PropertyMap.cpp
index b8c065d..f00272a 100644
--- a/libutils/PropertyMap.cpp
+++ b/libutils/PropertyMap.cpp
@@ -208,7 +208,7 @@
 
         mTokenizer->nextLine();
     }
-    return NO_ERROR;
+    return OK;
 }
 
 } // namespace android
diff --git a/libutils/String16.cpp b/libutils/String16.cpp
index 5c0b406..818b171 100644
--- a/libutils/String16.cpp
+++ b/libutils/String16.cpp
@@ -157,12 +157,12 @@
     if (begin >= N) {
         SharedBuffer::bufferFromData(mString)->release();
         mString = getEmptyString();
-        return NO_ERROR;
+        return OK;
     }
     if ((begin+len) > N) len = N-begin;
     if (begin == 0 && len == N) {
         setTo(other);
-        return NO_ERROR;
+        return OK;
     }
 
     if (&other == this) {
@@ -191,7 +191,7 @@
         memmove(str, other, len*sizeof(char16_t));
         str[len] = 0;
         mString = str;
-        return NO_ERROR;
+        return OK;
     }
     return NO_MEMORY;
 }
@@ -202,9 +202,9 @@
     const size_t otherLen = other.size();
     if (myLen == 0) {
         setTo(other);
-        return NO_ERROR;
+        return OK;
     } else if (otherLen == 0) {
-        return NO_ERROR;
+        return OK;
     }
 
     if (myLen >= SIZE_MAX / sizeof(char16_t) - otherLen) {
@@ -218,7 +218,7 @@
         char16_t* str = (char16_t*)buf->data();
         memcpy(str+myLen, other, (otherLen+1)*sizeof(char16_t));
         mString = str;
-        return NO_ERROR;
+        return OK;
     }
     return NO_MEMORY;
 }
@@ -228,9 +228,9 @@
     const size_t myLen = size();
     if (myLen == 0) {
         setTo(chrs, otherLen);
-        return NO_ERROR;
+        return OK;
     } else if (otherLen == 0) {
-        return NO_ERROR;
+        return OK;
     }
 
     if (myLen >= SIZE_MAX / sizeof(char16_t) - otherLen) {
@@ -245,7 +245,7 @@
         memcpy(str+myLen, chrs, otherLen*sizeof(char16_t));
         str[myLen+otherLen] = 0;
         mString = str;
-        return NO_ERROR;
+        return OK;
     }
     return NO_MEMORY;
 }
@@ -260,9 +260,9 @@
     const size_t myLen = size();
     if (myLen == 0) {
         return setTo(chrs, len);
-        return NO_ERROR;
+        return OK;
     } else if (len == 0) {
-        return NO_ERROR;
+        return OK;
     }
 
     if (pos > myLen) pos = myLen;
@@ -286,7 +286,7 @@
         #if 0
         printf("Result (%d chrs): %s\n", size(), String8(*this).string());
         #endif
-        return NO_ERROR;
+        return OK;
     }
     return NO_MEMORY;
 }
@@ -357,7 +357,7 @@
             edit[i] = tolower((char)v);
         }
     }
-    return NO_ERROR;
+    return OK;
 }
 
 status_t String16::replaceAll(char16_t replaceThis, char16_t withThis)
@@ -378,7 +378,7 @@
             edit[i] = withThis;
         }
     }
-    return NO_ERROR;
+    return OK;
 }
 
 status_t String16::remove(size_t len, size_t begin)
@@ -387,11 +387,11 @@
     if (begin >= N) {
         SharedBuffer::bufferFromData(mString)->release();
         mString = getEmptyString();
-        return NO_ERROR;
+        return OK;
     }
     if ((begin+len) > N) len = N-begin;
     if (begin == 0 && len == N) {
-        return NO_ERROR;
+        return OK;
     }
 
     if (begin > 0) {
@@ -410,7 +410,7 @@
         char16_t* str = (char16_t*)buf->data();
         str[len] = 0;
         mString = str;
-        return NO_ERROR;
+        return OK;
     }
     return NO_MEMORY;
 }
diff --git a/libutils/String8.cpp b/libutils/String8.cpp
index 8d318f7..0025c56 100644
--- a/libutils/String8.cpp
+++ b/libutils/String8.cpp
@@ -230,7 +230,7 @@
     const char *newString = allocFromUTF8(other, strlen(other));
     SharedBuffer::bufferFromData(mString)->release();
     mString = newString;
-    if (mString) return NO_ERROR;
+    if (mString) return OK;
 
     mString = getEmptyString();
     return NO_MEMORY;
@@ -241,7 +241,7 @@
     const char *newString = allocFromUTF8(other, len);
     SharedBuffer::bufferFromData(mString)->release();
     mString = newString;
-    if (mString) return NO_ERROR;
+    if (mString) return OK;
 
     mString = getEmptyString();
     return NO_MEMORY;
@@ -252,7 +252,7 @@
     const char *newString = allocFromUTF16(other, len);
     SharedBuffer::bufferFromData(mString)->release();
     mString = newString;
-    if (mString) return NO_ERROR;
+    if (mString) return OK;
 
     mString = getEmptyString();
     return NO_MEMORY;
@@ -263,7 +263,7 @@
     const char *newString = allocFromUTF32(other, len);
     SharedBuffer::bufferFromData(mString)->release();
     mString = newString;
-    if (mString) return NO_ERROR;
+    if (mString) return OK;
 
     mString = getEmptyString();
     return NO_MEMORY;
@@ -274,9 +274,9 @@
     const size_t otherLen = other.bytes();
     if (bytes() == 0) {
         setTo(other);
-        return NO_ERROR;
+        return OK;
     } else if (otherLen == 0) {
-        return NO_ERROR;
+        return OK;
     }
 
     return real_append(other.string(), otherLen);
@@ -292,7 +292,7 @@
     if (bytes() == 0) {
         return setTo(other, otherLen);
     } else if (otherLen == 0) {
-        return NO_ERROR;
+        return OK;
     }
 
     return real_append(other, otherLen);
@@ -311,7 +311,7 @@
 
 status_t String8::appendFormatV(const char* fmt, va_list args)
 {
-    int n, result = NO_ERROR;
+    int n, result = OK;
     va_list tmp_args;
 
     /* args is undefined after vsnprintf.
@@ -346,7 +346,7 @@
         str += myLen;
         memcpy(str, other, otherLen);
         str[otherLen] = '\0';
-        return NO_ERROR;
+        return OK;
     }
     return NO_MEMORY;
 }
@@ -382,7 +382,7 @@
         mString = str;
     }
 
-    return NO_ERROR;
+    return OK;
 }
 
 ssize_t String8::find(const char* other, size_t start) const
diff --git a/libutils/Threads.cpp b/libutils/Threads.cpp
index 43ec6c1..64bc402 100644
--- a/libutils/Threads.cpp
+++ b/libutils/Threads.cpp
@@ -379,7 +379,7 @@
 {
     DWORD dwWaitResult;
     dwWaitResult = WaitForSingleObject((HANDLE) mState, INFINITE);
-    return dwWaitResult != WAIT_OBJECT_0 ? -1 : NO_ERROR;
+    return dwWaitResult != WAIT_OBJECT_0 ? -1 : OK;
 }
 
 void Mutex::unlock()
@@ -506,7 +506,7 @@
         ReleaseMutex(condState->internalMutex);
         WaitForSingleObject(hMutex, INFINITE);
 
-        return res == WAIT_OBJECT_0 ? NO_ERROR : -1;
+        return res == WAIT_OBJECT_0 ? OK : -1;
     }
 } WinCondition;
 
@@ -639,13 +639,15 @@
  */
 
 Thread::Thread(bool canCallJava)
-    :   mCanCallJava(canCallJava),
-        mThread(thread_id_t(-1)),
-        mLock("Thread::mLock"),
-        mStatus(NO_ERROR),
-        mExitPending(false), mRunning(false)
+    : mCanCallJava(canCallJava),
+      mThread(thread_id_t(-1)),
+      mLock("Thread::mLock"),
+      mStatus(OK),
+      mExitPending(false),
+      mRunning(false)
 #if defined(__ANDROID__)
-        , mTid(-1)
+      ,
+      mTid(-1)
 #endif
 {
 }
@@ -656,7 +658,7 @@
 
 status_t Thread::readyToRun()
 {
-    return NO_ERROR;
+    return OK;
 }
 
 status_t Thread::run(const char* name, int32_t priority, size_t stack)
@@ -672,7 +674,7 @@
 
     // reset status and exitPending to their default value, so we can
     // try again after an error happened (either below, or in readyToRun())
-    mStatus = NO_ERROR;
+    mStatus = OK;
     mExitPending = false;
     mThread = thread_id_t(-1);
 
@@ -700,10 +702,10 @@
     }
 
     // Do not refer to mStatus here: The thread is already running (may, in fact
-    // already have exited with a valid mStatus result). The NO_ERROR indication
+    // already have exited with a valid mStatus result). The OK indication
     // here merely indicates successfully starting the thread and does not
     // imply successful termination/execution.
-    return NO_ERROR;
+    return OK;
 
     // Exiting scope of mLock is a memory barrier and allows new thread to run
 }
@@ -728,7 +730,7 @@
         if (first) {
             first = false;
             self->mStatus = self->readyToRun();
-            result = (self->mStatus == NO_ERROR);
+            result = (self->mStatus == OK);
 
             if (result && !self->exitPending()) {
                 // Binder threads (and maybe others) rely on threadLoop
diff --git a/libutils/Tokenizer.cpp b/libutils/Tokenizer.cpp
index f73d699..98dd2fd 100644
--- a/libutils/Tokenizer.cpp
+++ b/libutils/Tokenizer.cpp
@@ -48,7 +48,7 @@
 status_t Tokenizer::open(const String8& filename, Tokenizer** outTokenizer) {
     *outTokenizer = nullptr;
 
-    int result = NO_ERROR;
+    int result = OK;
     int fd = ::open(filename.string(), O_RDONLY);
     if (fd < 0) {
         result = -errno;
diff --git a/libutils/VectorImpl.cpp b/libutils/VectorImpl.cpp
index e16f88d..c97a19b 100644
--- a/libutils/VectorImpl.cpp
+++ b/libutils/VectorImpl.cpp
@@ -61,7 +61,7 @@
         "[%p] subclasses of VectorImpl must call finish_vector()"
         " in their destructor. Leaking %d bytes.",
         this, (int)(mCount*mItemSize));
-    // We can't call _do_destroy() here because the vtable is already gone. 
+    // We can't call _do_destroy() here because the vtable is already gone.
 }
 
 VectorImpl& VectorImpl::operator = (const VectorImpl& rhs)
@@ -197,7 +197,7 @@
                 _do_copy(temp, item, 1);
 
                 ssize_t j = i-1;
-                void* next = reinterpret_cast<char*>(array) + mItemSize*(i);                    
+                void* next = reinterpret_cast<char*>(array) + mItemSize*(i);
                 do {
                     _do_destroy(next, 1);
                     _do_copy(next, curr, 1);
@@ -214,13 +214,13 @@
             }
             i++;
         }
-        
+
         if (temp) {
             _do_destroy(temp, 1);
             free(temp);
         }
     }
-    return NO_ERROR;
+    return OK;
 }
 
 void VectorImpl::pop()
@@ -354,7 +354,7 @@
 }
 
 ssize_t VectorImpl::resize(size_t size) {
-    ssize_t result = NO_ERROR;
+    ssize_t result = OK;
     if (size > mCount) {
         result = insertAt(mCount, size - mCount);
     } else if (size < mCount) {
@@ -370,7 +370,7 @@
         if (sb->release(SharedBuffer::eKeepStorage) == 1) {
             _do_destroy(mStorage, mCount);
             SharedBuffer::dealloc(sb);
-        } 
+        }
     }
 }
 
@@ -644,13 +644,13 @@
             }
         }
     }
-    return NO_ERROR;
+    return OK;
 }
 
 ssize_t SortedVectorImpl::merge(const SortedVectorImpl& vector)
 {
     // we've merging a sorted vector... nice!
-    ssize_t err = NO_ERROR;
+    ssize_t err = OK;
     if (!vector.isEmpty()) {
         // first take care of the case where the vectors are sorted together
         if (do_compare(vector.itemLocation(vector.size()-1), arrayImpl()) <= 0) {
@@ -677,4 +677,3 @@
 /*****************************************************************************/
 
 }; // namespace android
-
diff --git a/libutils/include/utils/Errors.h b/libutils/include/utils/Errors.h
index 7093a20..7aafe42 100644
--- a/libutils/include/utils/Errors.h
+++ b/libutils/include/utils/Errors.h
@@ -43,8 +43,8 @@
 #endif
 
 enum {
-    OK                = 0,    // Everything's swell.
-    NO_ERROR          = 0,    // No errors.
+    OK                = 0,    // Preferred constant for checking success.
+    NO_ERROR          = OK,   // Deprecated synonym for `OK`. Prefer `OK` because it doesn't conflict with Windows.
 
     UNKNOWN_ERROR       = (-2147483647-1), // INT32_MIN value
 
diff --git a/libutils/include/utils/Flattenable.h b/libutils/include/utils/Flattenable.h
index 0a19019..9d00602 100644
--- a/libutils/include/utils/Flattenable.h
+++ b/libutils/include/utils/Flattenable.h
@@ -190,11 +190,11 @@
     inline status_t flatten(void* buffer, size_t size) const {
         if (size < sizeof(T)) return NO_MEMORY;
         memcpy(buffer, static_cast<T const*>(this), sizeof(T));
-        return NO_ERROR;
+        return OK;
     }
     inline status_t unflatten(void const* buffer, size_t) {
         memcpy(static_cast<T*>(this), buffer, sizeof(T));
-        return NO_ERROR;
+        return OK;
     }
 };
 
diff --git a/libutils/include/utils/Functor.h b/libutils/include/utils/Functor.h
index c0c8d57..c458699 100644
--- a/libutils/include/utils/Functor.h
+++ b/libutils/include/utils/Functor.h
@@ -29,7 +29,7 @@
 public:
     Functor() {}
     virtual ~Functor() {}
-    virtual status_t operator ()(int /*what*/, void* /*data*/) { return NO_ERROR; }
+    virtual status_t operator()(int /*what*/, void* /*data*/) { return OK; }
 };
 
 }  // namespace android
diff --git a/libutils/include/utils/Tokenizer.h b/libutils/include/utils/Tokenizer.h
index bb25f37..61c5ff7 100644
--- a/libutils/include/utils/Tokenizer.h
+++ b/libutils/include/utils/Tokenizer.h
@@ -37,7 +37,7 @@
     /**
      * Opens a file and maps it into memory.
      *
-     * Returns NO_ERROR and a tokenizer for the file, if successful.
+     * Returns OK and a tokenizer for the file, if successful.
      * Otherwise returns an error and sets outTokenizer to NULL.
      */
     static status_t open(const String8& filename, Tokenizer** outTokenizer);
@@ -45,7 +45,7 @@
     /**
      * Prepares to tokenize the contents of a string.
      *
-     * Returns NO_ERROR and a tokenizer for the string, if successful.
+     * Returns OK and a tokenizer for the string, if successful.
      * Otherwise returns an error and sets outTokenizer to NULL.
      */
     static status_t fromContents(const String8& filename,
diff --git a/storaged/storaged_service.cpp b/storaged/storaged_service.cpp
index 17ea25b..45f1d4d 100644
--- a/storaged/storaged_service.cpp
+++ b/storaged/storaged_service.cpp
@@ -161,7 +161,7 @@
         storaged_sp->update_uid_io_interval(time_window);
     }
 
-    return NO_ERROR;
+    return OK;
 }
 
 binder::Status StoragedService::onUserStarted(int32_t userId) {
diff --git a/storaged/uid_info.cpp b/storaged/uid_info.cpp
index 58e3fd2..0f718de 100644
--- a/storaged/uid_info.cpp
+++ b/storaged/uid_info.cpp
@@ -32,7 +32,7 @@
         parcel->writeCString(task_it.second.comm.c_str());
         parcel->write(&task_it.second.io, sizeof(task_it.second.io));
     }
-    return NO_ERROR;
+    return OK;
 }
 
 status_t UidInfo::readFromParcel(const Parcel* parcel) {
@@ -48,5 +48,5 @@
         parcel->read(&task.io, sizeof(task.io));
         tasks[task.pid] = task;
     }
-    return NO_ERROR;
+    return OK;
 }