Arduino预处理器行为不正确，定义为WIFI_AP和WIFI_STA

Question

[Arduino.cc预处理器（截至2020年5月1日的最新版本）在尝试执行预处理器逻辑以识别定义的单词WIFI_AP或WIFI_STA时具有意外行为。

Example:
#define FOO WIFI_STA

#if (FOO) == (WIFI_AP)
   Serial.print ("if this the this is zero: ");
   Serial.print( ((FOO) == (WIFI_AP)));  // should eval to 0
   Serial.println( " then there is no way to reach here!!!");
#endif

结果在“如果这是零：0，那么就没有办法到达这里！！”

预期行为：预处理程序应该在打印语句中评估相同的逻辑，并在编译之前删除所有打印内容！

回归：1.不会针对所有可能定义的常数发生，仅发生在WIFI_STA和WIFI_AP。

2. WIFI_STA和WIFI_AP的计算结果分别为1和2。不知道类型。

3. grep在包含或arduino应用程序资源中找不到定义WIFI_STA和WIFI_AP的任何位置！

我真的很困惑。我想也许WIFI_STA是在预处理程序运行时未定义的常量。但是我不知道该怎么做/

完整代码将运行并显示预期结果和意外结果

#include <Arduino.h>
#include <ESP8266WiFi.h>


#define ONE 1
#define TWO 2
#define THREE 3

#define FOO ONE

#define WIFIACCESSMODE WIFI_STA

void setup_wifiActivate() {
    Serial.println(WIFIACCESSMODE);
    Serial.println(WIFI_STA);
    Serial.println(WIFI_AP);
    Serial.println(WIFI_AP_STA);

// select mode for connection
 WiFi.mode(WIFIACCESSMODE);
 // WiFi.mode(WIFI_AP);         //Only Access point
//  WiFi.mode(WIFI_STA);   //This line hides the viewing of ESP as wifi network
//  WiFi.mode(WIFI_AP_STA);   //Both AP hotspot and router client are enabled

#if (WIFIACCESSMODE) == (WIFI_AP)
       Serial.println("Wifi access mode is WIFI_AP");
       Serial.println( (WIFIACCESSMODE) );
       Serial.println((WIFI_AP) );
       Serial.println( (WIFIACCESSMODE) == (WIFI_AP) );
   //setup_WiFiAccessPoint();

#elif (WIFIACCESSMODE) == (WIFI_AP_STA)
   Serial.println("Wifi access mode is WIFI_AP_STA");
   // setup_WiFiAccessPoint();
  //  setup_WiFiRouter();


  #elif  (WIFIACCESSMODE) == (WIFI_STA)
      Serial.println("Wifi access mode is WIFI_STA");
   // setup_WiFiRouter();

    #else
      Serial.println("Wifi Access mode is Unknown");
    #endif



}

void setup() {
    // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Serialdone");

  #if FOO == TWO
    Serial.println(FOO);
    Serial.println(ONE);
    Serial.println(TWO);
    Serial.println(THREE);
    Serial.println(FOO == TWO);

    Serial.println("It's two");
  #elif FOO == ONE
        Serial.println(FOO);
    Serial.println(ONE);
    Serial.println(TWO);
    Serial.println(THREE);
    Serial.println(FOO == TWO);
    Serial.println("it's ONE");
  #elif FOO == THREEE
             Serial.println(FOO);
    Serial.println(ONE);
    Serial.println(TWO);
    Serial.println(THREE);
    Serial.println(FOO == TWO);
    Serial.println("it's THREE");
  #else
            Serial.println(FOO);
    Serial.println(ONE);
    Serial.println(TWO);
    Serial.println(THREE);
    Serial.println(FOO == TWO);
    Serial.println("it's Unknown");
  #endif
  setup_wifiActivate();
}

void loop() {
  // put your main code here, to run repeatedly:

}

我想做什么？我试图让用户写这样的东西：

// edit to set desired access mode  WIFI_AP  WIFI_STA WIFI_AP_STA
#define WIFIACCESSMODE WIFI_STA
...
then later:
WiFi.mode( WIFIACCESSMODE);
#if WIFIACCESSMODE == WIFI_STA   <<<---  this fails to work
  // do some code
#endif

有人可以告诉我

1. 问题的根源
2. 如何解决
3. 定义了WIFI_STA的位置。

我正在使用ESP8266，但此问题出在编译器而非设备中。

Answer 1

如果您查看ESP8266WiFi库-MacOSX对于内置软件包，按住Control键并单击/Applications/Arduino.app，然后从弹出菜单中选择“显示软件包内容”。从那里您可以深入到；

/Applications/Arduino.app/Contents/Resources/Java/packages

ESP8266软件包（至少在我的OSX Sierra上）Users\YOUR_USERNAME\Library\Arduino15\packages\esp8266\hardware\esp8266\2.7.1\libraries\ESP8266WiFi\srcWindows C:\Users\YOUR_USERNAME\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.7.1\libraries\ESP8266WiFi\src-在ESP8266WiFiType.h中找到以下定义

typedef enum WiFiMode 
{
    WIFI_OFF = 0, WIFI_STA = 1, WIFI_AP = 2, WIFI_AP_STA = 3,
    /* these two pseudo modes are experimental: */ WIFI_SHUTDOWN = 4, WIFI_RESUME = 8
} WiFiMode_t;

因此，对于您的应用程序，您必须使用：

if (WIFIACCESSMODE == WIFI_STA ) {do STA things}
if (WIFIACCESSMODE == WIFI_AP) {do AP things}

Answer 2

显然WIFI_STA和WIFI_AP是代码定义的常数，而不是预处理器定义。因此，选择这些值的唯一方法是使用显式代码，而不是通过C ++ if或case语句进行预处理器优化。

if (WIFIACCESSMODE == WIFI_AP) {
       Serial.println("Wifi access mode is WIFI_AP");
       Serial.println( (WIFIACCESSMODE) );
       Serial.println((WIFI_AP) );
       Serial.println( (WIFIACCESSMODE) == (WIFI_AP) );
   //setup_WiFiAccessPoint();
}
else if((WIFIACCESSMODE) == (WIFI_AP_STA)){
   Serial.println("Wifi access mode is WIFI_AP_STA");
   // setup_WiFiAccessPoint();
  //  setup_WiFiRouter();
}

else if ((WIFIACCESSMODE) == (WIFI_STA)) {
      Serial.println("Wifi access mode is WIFI_STA");
   // setup_WiFiRouter();
}
    else {
      Serial.println("Wifi Access mode is Unknown");
    }

作品。

无论如何我仍然不知道这些代码在何处定义。