Let us start here, from square one. No, from Zero!

util/logging.cpp

@@ -0,0 +1,14 @@
+#include "logging.h"
+
+std::string_view log_get_datetime() {
+    return log_get_datetime(time(nullptr));
+}
+
+std::string_view log_get_datetime(std::time_t now) {
+    static thread_local char buf[64];
+
+    // `localtime` on Windows is thread-safe
+    strftime(buf, sizeof(buf), "[%Y/%m/%d %X]", localtime(&now));
+
+    return buf;
+}