Question

当我在启用优化的情况下编译以下代码时

double bitrate = 8 * m_totBytes / (Simulator::Now() - m_startTime).GetSeconds();
double instBitrate = 8 * message.GetSize() / (Simulator::Now() - m_lastRecv).GetSeconds();
normBitrate = 0.1 * instBitrate + 0.9 * m_resolution;

NS_LOG_INFO("------RECEIVED: " << message.GetSize()
         << " Bitrate = " << bitrate
         << " instBit = " << instBitrate
         << " normBit = " << normBitrate);

我收到编译器警告说：

error: unused variable ‘bitrate’ [-Werror=unused-variable]

因为NS_LOG_INFO宏被编译器优化了。为了编译，我必须添加一个无用且丑陋的代码，如下所示：

if (false) { // For suppressing "Unused variable" warning when compiling with "-d optimiized"
    std::cout << bitrate << instBitrate << normBitrate << std::endl;
}

如何在不禁用警告，优化和没有垃圾代码的情况下编译它？

Answer 1

由于您没有使用该变量，除非在该实例中，为什么不这样做：

NS_LOG_INFO("------RECEIVED: " << message.GetSize()
     << " Bitrate = " << (8 * m_totBytes / (Simulator::Now() - m_startTime).GetSeconds())
     << " instBit = " << instBitrate
     << " normBit = " << normBitrate);

设置优化时未使用的变量警告

1 个答案: