diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 5024ef4..0b246e6 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -4,7 +4,7 @@ function(xtest_define_example NAME)
     if (NAME STREQUAL "all")
         target_compile_definitions(${TARGET_NAME} PRIVATE XTEST_ALL_EXAMPLES)
     endif ()
-    target_compile_options(${TARGET_NAME} PRIVATE -Wall -pedantic)
+    target_compile_options(${TARGET_NAME} PRIVATE -Wall -Wextra -pedantic)
 endfunction()
 
 
diff --git a/examples/assertions.c b/examples/assertions.c
index e1b3e7c..4c2b512 100644
--- a/examples/assertions.c
+++ b/examples/assertions.c
@@ -2,7 +2,7 @@
 #include "xtest.h"
 #include "source.h"
 
-void test_assert(void *fixture, void **params) {
+void test_assert() {
     int i1 = 1;
     int i2 = 1;
     int i3 = 2;
@@ -32,7 +32,7 @@ void test_assert(void *fixture, void **params) {
     xtest_assert(ret_1());
 }
 
-void test_assert_is(void *fixture, void **params) {
+void test_assert_is() {
     int i1 = 1;
     int i2 = 1;
     int i3 = 2;
@@ -66,7 +66,7 @@ void test_assert_is(void *fixture, void **params) {
     xtest_assert_is_not(b1, b3);
 }
 
-void test_assert_str_is(void *fixture, void **params) {
+void test_assert_str_is() {
     const char *s1 = "ret_1";
     const char *s2 = "ret_1";
     const char *s3 = "bar";
@@ -75,7 +75,7 @@ void test_assert_str_is(void *fixture, void **params) {
     xtest_assert_str_is_not(s1, s3);
 }
 
-void test_assert_mem_is(void *fixture, void **params) {
+void test_assert_mem_is() {
     char m1[100];
     char m2[100];
     for (int i = 0; i < 100; ++i) {
diff --git a/examples/parameterized.c b/examples/parameterized.c
index 3533dad..6f7e17b 100644
--- a/examples/parameterized.c
+++ b/examples/parameterized.c
@@ -2,16 +2,16 @@
 #include "xtest.h"
 #include "source.h"
 
-void test_add(void *fixture, void **params) {
+void test_add(XTEST_UNUSED void *fixture, void **params) {
     int a = xtest_get_param(int, 0, params);
     int b = xtest_get_param(int, 1, params);
     int result = a + b;
     xtest_assert_is(add(a, b), result);
 }
 
-void test_str_equals(void *fixture, void **params) {
-    const char* s1 = xtest_get_param_ptr(const char*, 0, params);
-    const char* s2 = xtest_get_param_ptr(const char*, 1, params);
+void test_str_equals(XTEST_UNUSED void *fixture, void **params) {
+    const char *s1 = xtest_get_param_ptr(const char*, 0, params);
+    const char *s2 = xtest_get_param_ptr(const char*, 1, params);
     if (str_equals(s1, s2)) {
         xtest_assert_str_is(s1, s2);
     } else {
diff --git a/include/xtest/xtest.h b/include/xtest/xtest.h
index dd013e4..737600f 100644
--- a/include/xtest/xtest.h
+++ b/include/xtest/xtest.h
@@ -5,6 +5,12 @@
 #error "do not include xtest.h before assert.h. If your tests make use of standard library assertions, include first xtest.h and then assert.h"
 #endif
 
+#if defined(__GNUC__) || defined(__clang__)
+#define XTEST_UNUSED __attribute__((unused))
+#else
+#define XTEST_UNUSED
+#endif
+
 
 #include <string.h>
 #include <stdint.h>
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b0ca476..a9bf19f 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,6 +1,6 @@
 
 add_library(xtest xtest.c)
 target_compile_definitions(xtest PRIVATE XTEST)
-target_compile_options(xtest PRIVATE -Wall -pedantic)
+target_compile_options(xtest PRIVATE -Wall -Wextra -pedantic)
 target_include_directories(xtest PRIVATE ../extern/pcg ../include/xtest)