c - ArduinoJSON 未定义对 `__cxa_guard_acquire' 的引用

Question

我正在绘制草图，我正在使用 ArduinoJSON。我想我可能会解决这个问题，看看人们是否看到了这个错误。

WifiNest.cpp.o:(.text._ZN11ArduinoJson9JsonArray7invalidEv[_ZN11ArduinoJson9JsonArray7invalidEv]+0x8): undefined reference to `__cxa_guard_acquire'
WifiNest.cpp.o:(.text._ZN11ArduinoJson9JsonArray7invalidEv[_ZN11ArduinoJson9JsonArray7invalidEv]+0xc): undefined reference to `__cxa_guard_release'
WifiNest.cpp.o: In function `ArduinoJson::JsonArray::invalid()':
C:\Program Files (x86)\Arduino/WifiNest.ino:156: undefined reference to `__cxa_guard_acquire'
C:\Program Files (x86)\Arduino/WifiNest.ino:156: undefined reference to `__cxa_guard_release'
WifiNest.cpp.o: In function `ArduinoJson::JsonObject::invalid()':
C:\Program Files (x86)\Arduino/WifiNest.ino:156: undefined reference to `__cxa_guard_acquire'
C:\Program Files (x86)\Arduino/WifiNest.ino:156: undefined reference to `__cxa_guard_release'
collect2.exe: error: ld returned 1 exit status
Error compiling.

这是我创建 jsonArray 对象的 Arduino 代码的一部分:

char jsonArray [result.length()+1];
result.toCharArray(jsonArray,sizeof(jsonArray));
jsonArray[result.length() + 1] = '\0';

DynamicJsonBuffer json_buf;
JsonObject &root = json_buf.parseObject(jsonArray);
if (!root.success())
{
    Serial.println("parseObject() failed");
}

这里是 JSONArray 无效函数:

static JsonArray &invalid() {
    static JsonArray instance(NULL);
    return instance;
}

这里是 JSONObject 无效函数:

// Returns a reference an invalid JsonObject.
// This object is meant to replace a NULL pointer.
// This is used when memory allocation or JSON parsing fail.
static JsonObject& invalid() {
    static JsonObject instance(NULL);
    return instance;
}

Answer 1

尝试使用以下编译标志:

-fno-threadsafe-statics

Do not emit the extra code to use the routines specified in the C++ ABI for thread-safe initialization of local statics. You can use this option to reduce code size slightly in code that doesn't need to be thread-safe.

查看问题 #356和 #361