diff --git a/src/shared/main-func.h b/src/shared/main-func.h
index 67537555a12ea..e55655108e9d0 100644
--- a/src/shared/main-func.h
+++ b/src/shared/main-func.h
@@ -20,6 +20,7 @@
 
 #define _DEFINE_MAIN_FUNCTION(intro, impl, result_to_exit_status, result_to_return_value) \
         int main(int argc, char *argv[]) {                              \
+                errno = 0;                                              \
                 int r;                                                  \
                 assert_se(argc > 0 && !isempty(argv[0]));               \
                 save_argc_argv(argc, argv);                             \
diff --git a/src/shared/tests.h b/src/shared/tests.h
index 141bfe4f22d87..e3040c6cde7fa 100644
--- a/src/shared/tests.h
+++ b/src/shared/tests.h
@@ -184,6 +184,7 @@ static inline int run_test_table(void) {
 
 #define DEFINE_TEST_MAIN_FULL(log_level, intro, outro)    \
         int main(int argc, char *argv[]) {                \
+                errno = 0;                                \
                 int (*_intro)(void) = intro;              \
                 int (*_outro)(void) = outro;              \
                 int _r, _q;                               \