Arduino IDE 无法识别结构

Question

我正在尝试使用 ESP-NOW 从客户端向服务器发送 2 个 int 变量。客户端完整代码为：

/**
   ESPNOW - Basic communication - Master
   Date: 26th September 2017
   Author: Arvind Ravulavaru <https://github.com/arvindr21>
   Purpose: ESPNow Communication between a Master ESP32 and a Slave ESP32
   Description: This sketch consists of the code for the Master module.
   Resources: (A bit outdated)
   a. https://espressif.com/sites/default/files/documentation/esp-now_user_guide_en.pdf
   b. http://www.esploradores.com/practica-6-conexion-esp-now/

   << This Device Master >>

   Flow: Master
   Step 1 : ESPNow Init on Master and set it in STA mode
   Step 2 : Start scanning for Slave ESP32 (we have added a prefix of `slave` to the SSID of slave for an easy setup)
   Step 3 : Once found, add Slave as peer
   Step 4 : Register for send callback
   Step 5 : Start Transmitting data from Master to Slave

   Flow: Slave
   Step 1 : ESPNow Init on Slave
   Step 2 : Update the SSID of Slave with a prefix of `slave`
   Step 3 : Set Slave in AP mode
   Step 4 : Register for receive callback and wait for data
   Step 5 : Once data arrives, print it in the serial monitor

   Note: Master and Slave have been defined to easily understand the setup.
         Based on the ESPNOW API, there is no concept of Master and Slave.
         Any devices can act as master or salve.
*/

#include <esp_now.h>
#include <WiFi.h>

// Global copy of slave
esp_now_peer_info_t slave;
#define CHANNEL 1
#define PRINTSCANRESULTS 0
#define DELETEBEFOREPAIR 0

// Init ESP Now with fallback
void InitESPNow() {
  WiFi.disconnect();
  if (esp_now_init() == ESP_OK) {
    Serial.println("ESPNow Init Success");
  }
  else {
    Serial.println("ESPNow Init Failed");
    // Retry InitESPNow, add a counte and then restart?
    // InitESPNow();
    // or Simply Restart
    ESP.restart();
  }
}

// Scan for slaves in AP mode
void ScanForSlave() {
  int8_t scanResults = WiFi.scanNetworks();
  // reset on each scan
  bool slaveFound = 0;
  memset(&slave, 0, sizeof(slave));

  Serial.println("");
  if (scanResults == 0) {
    Serial.println("No WiFi devices in AP Mode found");
  } else {
    Serial.print("Found "); Serial.print(scanResults); Serial.println(" devices ");
    for (int i = 0; i < scanResults; ++i) {
      // Print SSID and RSSI for each device found
      String SSID = WiFi.SSID(i);
      int32_t RSSI = WiFi.RSSI(i);
      String BSSIDstr = WiFi.BSSIDstr(i);

      if (PRINTSCANRESULTS) {
        Serial.print(i + 1);
        Serial.print(": ");
        Serial.print(SSID);
        Serial.print(" (");
        Serial.print(RSSI);
        Serial.print(")");
        Serial.println("");
      }
      delay(10);
      // Check if the current device starts with `Slave`
      if (SSID.indexOf("Slave") == 0) {
        // SSID of interest
        Serial.println("Found a Slave.");
        Serial.print(i + 1); Serial.print(": "); Serial.print(SSID); Serial.print(" ["); Serial.print(BSSIDstr); Serial.print("]"); Serial.print(" ("); Serial.print(RSSI); Serial.print(")"); Serial.println("");
        // Get BSSID => Mac Address of the Slave
        int mac[6];
        if ( 6 == sscanf(BSSIDstr.c_str(), "%x:%x:%x:%x:%x:%x",  &mac[0], &mac[1], &mac[2], &mac[3], &mac[4], &mac[5] ) ) {
          for (int ii = 0; ii < 6; ++ii ) {
            slave.peer_addr[ii] = (uint8_t) mac[ii];
          }
        }

        slave.channel = CHANNEL; // pick a channel
        slave.encrypt = 0; // no encryption

        slaveFound = 1;
        // we are planning to have only one slave in this example;
        // Hence, break after we find one, to be a bit efficient
        break;
      }
    }
  }

  if (slaveFound) {
    Serial.println("Slave Found, processing..");
  } else {
    Serial.println("Slave Not Found, trying again.");
  }

  // clean up ram
  WiFi.scanDelete();
}

// Check if the slave is already paired with the master.
// If not, pair the slave with master
bool manageSlave() {
  if (slave.channel == CHANNEL) {
    if (DELETEBEFOREPAIR) {
      deletePeer();
    }

    Serial.print("Slave Status: ");
    // check if the peer exists
    bool exists = esp_now_is_peer_exist(slave.peer_addr);
    if ( exists) {
      // Slave already paired.
      Serial.println("Already Paired");
      return true;
    } else {
      // Slave not paired, attempt pair
      esp_err_t addStatus = esp_now_add_peer(&slave);
      if (addStatus == ESP_OK) {
        // Pair success
        Serial.println("Pair success");
        return true;
      } else if (addStatus == ESP_ERR_ESPNOW_NOT_INIT) {
        // How did we get so far!!
        Serial.println("ESPNOW Not Init");
        return false;
      } else if (addStatus == ESP_ERR_ESPNOW_ARG) {
        Serial.println("Invalid Argument");
        return false;
      } else if (addStatus == ESP_ERR_ESPNOW_FULL) {
        Serial.println("Peer list full");
        return false;
      } else if (addStatus == ESP_ERR_ESPNOW_NO_MEM) {
        Serial.println("Out of memory");
        return false;
      } else if (addStatus == ESP_ERR_ESPNOW_EXIST) {
        Serial.println("Peer Exists");
        return true;
      } else {
        Serial.println("Not sure what happened");
        return false;
      }
    }
  } else {
    // No slave found to process
    Serial.println("No Slave found to process");
    return false;
  }
}

void deletePeer() {
  esp_err_t delStatus = esp_now_del_peer(slave.peer_addr);
  Serial.print("Slave Delete Status: ");
  if (delStatus == ESP_OK) {
    // Delete success
    Serial.println("Success");
  } else if (delStatus == ESP_ERR_ESPNOW_NOT_INIT) {
    // How did we get so far!!
    Serial.println("ESPNOW Not Init");
  } else if (delStatus == ESP_ERR_ESPNOW_ARG) {
    Serial.println("Invalid Argument");
  } else if (delStatus == ESP_ERR_ESPNOW_NOT_FOUND) {
    Serial.println("Peer not found.");
  } else {
    Serial.println("Not sure what happened");
  }
}

//=================DATA======================

typedef struct test_struct {
  int x;
  int y;
} test_struct;

test_struct test;
  test.x = 10;
  test.y = 20;

//uint8_t data = 0;
// send data
void sendData() {
  //data++;
  const uint8_t *peer_addr = slave.peer_addr;
  Serial.print("Sending: "); Serial.println(test);
  esp_err_t result = esp_now_send(peer_addr, (uint8_t *) &test,
    sizeof(test_struct));
  Serial.print("Send Status: ");
  if (result == ESP_OK) {
    Serial.println("Success");
  } else if (result == ESP_ERR_ESPNOW_NOT_INIT) {
    // How did we get so far!!
    Serial.println("ESPNOW not Init.");
  } else if (result == ESP_ERR_ESPNOW_ARG) {
    Serial.println("Invalid Argument");
  } else if (result == ESP_ERR_ESPNOW_INTERNAL) {
    Serial.println("Internal Error");
  } else if (result == ESP_ERR_ESPNOW_NO_MEM) {
    Serial.println("ESP_ERR_ESPNOW_NO_MEM");
  } else if (result == ESP_ERR_ESPNOW_NOT_FOUND) {
    Serial.println("Peer not found.");
  } else {
    Serial.println("Not sure what happened");
  }
}

// callback when data is sent from Master to Slave
void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {
  char macStr[18];
  snprintf(macStr, sizeof(macStr), "%02x:%02x:%02x:%02x:%02x:%02x",
           mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
  Serial.print("Last Packet Sent to: "); Serial.println(macStr);
  Serial.print("Last Packet Send Status: "); Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
}

void setup() {
  Serial.begin(115200);
  //Set device in STA mode to begin with
  WiFi.mode(WIFI_STA);
  Serial.println("ESPNow/Basic/Master Example");
  // This is the mac address of the Master in Station Mode
  Serial.print("STA MAC: "); Serial.println(WiFi.macAddress());
  // Init ESPNow with a fallback logic
  InitESPNow();
  // Once ESPNow is successfully Init, we will register for Send CB to
  // get the status of Trasnmitted packet
  esp_now_register_send_cb(OnDataSent);
}

void loop() {
  // In the loop we scan for slave
  ScanForSlave();
  // If Slave is found, it would be populate in `slave` variable
  // We will check if `slave` is defined and then we proceed further
  if (slave.channel == CHANNEL) { // check if slave channel is defined
    // `slave` is defined
    // Add slave as peer if it has not been added already
    bool isPaired = manageSlave();
    if (isPaired) {
      // pair success or already paired
      // Send data to device
      sendData();
    } else {
      // slave pair failed
      Serial.println("Slave pair failed!");
    }
  }
  else {
    // No slave found to process
  }

  // wait for 3seconds to run the logic again
  delay(3000);
}

当发送的数据仅为 0 时一切正常，当我替换这个结构时（它刚好超过主代码中的 =========DATA======== 行）

typedef struct test_struct {
  int x;
  int y;
} test_struct;

test_struct test;
  test.x = 10;
  test.y = 20;

我收到一条错误消息 'test' 没有命名类型。

有什么想法吗？

Answer 1

我明白了，结构定义必须在函数内部，无论是设置还是任何其他。谢谢大家看这个

好的，我想我明白了，但我只是写了另一个草图并将结构放在所有函数之前并且它正在工作，所以老实说我不知道发生了什么，其他人知道答案，或者这个问题是不是愚蠢到没有人愿意评论？这对我来说很好，我在这方面仍然是一个很好的新手，所以如果你能帮忙，很好，如果不能，无论如何，谢谢你，这对新手来说仍然是一个很好的资源

Answer 2

您正在尝试分配一个值以在任何可执行代码之外进行测试。定义很好，赋值 test.x=10 是需要在新函数或现有函数（如 setup() 或 loop()）中执行的代码。尝试在初始化期间分配值，如下所示。这样编译器在为该变量分配内存时将值放入。

typedef struct{
    int x;
    int y;
} test_struct;
test_struct t={10,20};

Arduino IDE 无法识别结构

Arduino IDE does not recognize struct

arduino-ide

arduino-c++

arduino-esp32