diff --git a/libcutils/android_reboot.cpp b/libcutils/android_reboot.cpp
index 5e864d4..ce41cd3 100644
--- a/libcutils/android_reboot.cpp
+++ b/libcutils/android_reboot.cpp
@@ -23,7 +23,7 @@
 
 #define TAG "android_reboot"
 
-int android_reboot(int cmd, int flags __unused, const char* arg) {
+int android_reboot(int cmd, int /*flags*/, const char* arg) {
     int ret;
     const char* restart_cmd = NULL;
     char* prop_value;
diff --git a/libcutils/ashmem-host.cpp b/libcutils/ashmem-host.cpp
index d2c28f3..b2bec99 100644
--- a/libcutils/ashmem-host.cpp
+++ b/libcutils/ashmem-host.cpp
@@ -35,12 +35,7 @@
 
 #include <utils/Compat.h>
 
-#ifndef __unused
-#define __unused __attribute__((__unused__))
-#endif
-
-int ashmem_create_region(const char *ignored __unused, size_t size)
-{
+int ashmem_create_region(const char* /*ignored*/, size_t size) {
     char pattern[PATH_MAX];
     snprintf(pattern, sizeof(pattern), "/tmp/android-ashmem-%d-XXXXXXXXX", getpid());
     int fd = mkstemp(pattern);
@@ -56,18 +51,15 @@
     return fd;
 }
 
-int ashmem_set_prot_region(int fd __unused, int prot __unused)
-{
+int ashmem_set_prot_region(int /*fd*/, int /*prot*/) {
     return 0;
 }
 
-int ashmem_pin_region(int fd __unused, size_t offset __unused, size_t len __unused)
-{
+int ashmem_pin_region(int /*fd*/, size_t /*offset*/, size_t /*len*/) {
     return 0 /*ASHMEM_NOT_PURGED*/;
 }
 
-int ashmem_unpin_region(int fd __unused, size_t offset __unused, size_t len __unused)
-{
+int ashmem_unpin_region(int /*fd*/, size_t /*offset*/, size_t /*len*/) {
     return 0 /*ASHMEM_IS_UNPINNED*/;
 }
 
diff --git a/libcutils/sched_policy.cpp b/libcutils/sched_policy.cpp
index 0e6d333..f5ce82f 100644
--- a/libcutils/sched_policy.cpp
+++ b/libcutils/sched_policy.cpp
@@ -27,8 +27,6 @@
 
 #include <log/log.h>
 
-#define UNUSED __attribute__((__unused__))
-
 /* Re-map SP_DEFAULT to the system default policy, and leave other values unchanged.
  * Call this any place a SchedPolicy is used as an input parameter.
  * Returns the possibly re-mapped policy.
@@ -445,13 +443,11 @@
 
 /* Stubs for non-Android targets. */
 
-int set_sched_policy(int tid UNUSED, SchedPolicy policy UNUSED)
-{
+int set_sched_policy(int /*tid*/, SchedPolicy /*policy*/) {
     return 0;
 }
 
-int get_sched_policy(int tid UNUSED, SchedPolicy *policy)
-{
+int get_sched_policy(int /*tid*/, SchedPolicy* policy) {
     *policy = SP_SYSTEM_DEFAULT;
     return 0;
 }
diff --git a/libcutils/socket_local_client_unix.cpp b/libcutils/socket_local_client_unix.cpp
index 68b2b0c..d2b4909 100644
--- a/libcutils/socket_local_client_unix.cpp
+++ b/libcutils/socket_local_client_unix.cpp
@@ -39,8 +39,6 @@
 
 #include "socket_local_unix.h"
 
-#define UNUSED __attribute__((unused))
-
 #define LISTEN_BACKLOG 4
 
 /* Documented in header file. */
@@ -123,9 +121,7 @@
  * 
  * Used by AndroidSocketImpl
  */
-int socket_local_client_connect(int fd, const char *name, int namespaceId, 
-        int type UNUSED)
-{
+int socket_local_client_connect(int fd, const char* name, int namespaceId, int /*type*/) {
     struct sockaddr_un addr;
     socklen_t alen;
     int err;
diff --git a/libcutils/str_parms.cpp b/libcutils/str_parms.cpp
index 139d62f..f5a52a7 100644
--- a/libcutils/str_parms.cpp
+++ b/libcutils/str_parms.cpp
@@ -30,8 +30,6 @@
 #include <cutils/memory.h>
 #include <log/log.h>
 
-#define UNUSED __attribute__((unused))
-
 /* When an object is allocated but not freed in a function,
  * because its ownership is released to other object like a hashmap,
  * call RELEASE_OWNERSHIP to tell the clang analyzer and avoid
@@ -364,8 +362,7 @@
     return str;
 }
 
-static bool dump_entry(void *key, void *value, void *context UNUSED)
-{
+static bool dump_entry(void* key, void* value, void* /*context*/) {
     ALOGI("key: '%s' value: '%s'\n", (char *)key, (char *)value);
     return true;
 }
diff --git a/libcutils/trace-host.cpp b/libcutils/trace-host.cpp
index 05842cd..d47cc18 100644
--- a/libcutils/trace-host.cpp
+++ b/libcutils/trace-host.cpp
@@ -16,21 +16,17 @@
 
 #include <cutils/trace.h>
 
-#ifndef __unused
-#define __unused __attribute__((__unused__))
-#endif
-
 atomic_bool             atrace_is_ready      = ATOMIC_VAR_INIT(true);
 int                     atrace_marker_fd     = -1;
 uint64_t                atrace_enabled_tags  = 0;
 
-void atrace_set_debuggable(bool debuggable __unused) { }
-void atrace_set_tracing_enabled(bool enabled __unused) { }
+void atrace_set_debuggable(bool /*debuggable*/) {}
+void atrace_set_tracing_enabled(bool /*enabled*/) {}
 void atrace_update_tags() { }
 void atrace_setup() { }
-void atrace_begin_body(const char* name __unused) { }
+void atrace_begin_body(const char* /*name*/) {}
 void atrace_end_body() { }
-void atrace_async_begin_body(const char* name __unused, int32_t cookie __unused) { }
-void atrace_async_end_body(const char* name __unused, int32_t cookie __unused) { }
-void atrace_int_body(const char* name __unused, int32_t value __unused) { }
-void atrace_int64_body(const char* name __unused, int64_t value __unused) { }
+void atrace_async_begin_body(const char* /*name*/, int32_t /*cookie*/) {}
+void atrace_async_end_body(const char* /*name*/, int32_t /*cookie*/) {}
+void atrace_int_body(const char* /*name*/, int32_t /*value*/) {}
+void atrace_int64_body(const char* /*name*/, int64_t /*value*/) {}