common/logger.h (13 lines of code) (raw):
#pragma once
#include "fmt/format.h"
#include <iostream>
namespace Hessian2 {
#ifdef HESSIAN_LOG_OUTPUT
#define HESSIAN_LOG(level, args...) \
do { \
std::cerr << "" << #level << ":\t" << fmt::format(args) << std::endl; \
} while (0)
#else
#define HESSIAN_LOG(level, args...)
#endif
} // namespace Hessian2