diff --git a/main/php_syslog.c b/main/php_syslog.c
index b90719609ea..fa71a863134 100644
--- a/main/php_syslog.c
+++ b/main/php_syslog.c
@@ -77,7 +77,7 @@ void php_openlog(const char *ident, int option, int facility)
 	PG(have_called_openlog) = 1;
 }
 
-void php_closelog()
+void php_closelog(void)
 {
 	closelog();
 	PG(have_called_openlog) = 0;
diff --git a/main/php_syslog.h b/main/php_syslog.h
index e39de02bd05..f2682d74f23 100644
--- a/main/php_syslog.h
+++ b/main/php_syslog.h
@@ -38,7 +38,7 @@ BEGIN_EXTERN_C()
 PHPAPI void php_syslog_str(int priority, const zend_string* message);
 PHPAPI void php_syslog(int, const char *format, ...);
 PHPAPI void php_openlog(const char *, int, int);
-PHPAPI void php_closelog();
+PHPAPI void php_closelog(void);
 END_EXTERN_C()
 
 #endif