Question

我正在通过push_back（）将元素添加到c ++ 11列表中。在添加元素之前，我正在通过cout打印出调试消息。现在，当我删除cout语句时，我使用push_back追加到列表的元素中的值已损坏。我可以使用googletest进行测试。

下面您将看到工作代码。当我注释掉cout语句时，sensor_scan_list的最后一个元素中的值似乎已损坏。在我看来，错误在于表的实例化或测试代码中。仅current_sensor.state的状态变量似乎已损坏（请参见下文）。

当我保留cout语句时，一切正常。这是一个很奇怪的问题，有人知道为什么会发生这种情况吗？

代码段：

void MessageHandler::processSensorHeader(TelemetryMessageInterface * p_Message)
{
    cout << "DEBUG: sensor header element added\n";
    addSensorHeader(p_Message);
    send_message(encoder->confirm(((SensorHeaderMessage *)p_Message)->getMessageId())); //ACK
}

void MessageHandler::addSensorHeader(TelemetryMessageInterface * p_message)
{
    Sensor new_sensor;

    new_sensor.manufacturerId = ((SensorHeaderMessage *)p_message)->getManufacturerId();
    new_sensor.deviceId = ((SensorHeaderMessage *)p_message)->getDeviceId();
    new_sensor.state |= SENSOR_HEADER_DETECTED;

    sensor_scan_list.push_back(new_sensor);
}

Googletest代码：

TEST(MessageHandlerTest, processSensorHeader)
{
TelemetryEncoder * encoder = new TelemetryEncoder();
TelemetryMessageInterface * p_Message;
MessageHandler message_handler;
Sensor current_sensor;

list <Sensor> :: iterator p_List;

p_Message = encoder->encodeSensorHeader(0x0101,0x0202,0x0303); 
//add sensor
message_handler.processSensorHeader(p_Message);

p_List = message_handler.sensor_scan_list.begin();

current_sensor = *p_List;
EXPECT_EQ(current_sensor.deviceId, 0x0303);
EXPECT_EQ(current_sensor.manufacturerId, 0x0202);
EXPECT_EQ(current_sensor.state, 1);

p_Message = encoder->encodeSensorHeader(0x0203,0x0302,0x0403); 
//add new sensor
message_handler.processSensorHeader(p_Message);

current_sensor = *++p_List;
EXPECT_EQ(current_sensor.deviceId, 0x0403);
EXPECT_EQ(current_sensor.manufacturerId, 0x0302);
EXPECT_EQ(current_sensor.state, 1);

p_Message = encoder->encodeSensorHeader(0x0102,0x0202,0x0303);
message_handler.processSensorHeader(p_Message);

current_sensor = *++p_List;
EXPECT_EQ(current_sensor.deviceId, 0x0303);
EXPECT_EQ(current_sensor.manufacturerId, 0x0202);
EXPECT_EQ(current_sensor.state, 1);
}

传感器类别：

class Sensor : public sensor_interface {
public:
Sensor();
virtual ~Sensor();

uint16_t manufacturerId;
uint16_t deviceId;

char name[SENSOR_INFORMATION_LENGTH];

uint8_t state;
};

Googletest输出的错误代码（注释已注释掉）：

[ RUN      ] MessageHandlerTest.processSensorHeader
../test/inc/test_messageHandler.cpp:77: Failure
  Expected: current_sensor.state
  Which is: '\xC1' (193)
To be equal to: 1
../test/inc/test_messageHandler.cpp:93: Failure
  Expected: current_sensor.state
  Which is: '\xF1' (241)
To be equal to: 1
[  FAILED  ] MessageHandlerTest.processSensorHeader (0 ms)

Answer 1

public Date? start_date { get; set; }成员变量具有错误值的问题可能是由于state类未在构造上初始化Sensor所致。

因此，将state应用于未初始化的变量将导致结果不一致或错误。

当然，解决方法是确保成员具有已知的构造初始值，在这种情况下，|=在初始化state时应为0。

c ++ 11 list push_back（）实例化错误？

1 个答案: