Getting error: incompatible types in assignment of 'const char*' to 'char [100]'

Question

I am trying to save a char to EEPROM and then retrieve it. I am using an ESP32-CAM with this code and the Arduino IDE:

#include <EEPROM.h>

int addr = 0; 
char ssidString[100] = {0};
float floatFromPC2 = 0;
char pskString[100] = {0};
    
void setup() {
  if (!ssidString == "") {
    EEPROM.begin(512);          //Initialize EEPROM
    EEPROM.write(addr, 'A');    //Write character A
    addr++;                     //Increment address
    EEPROM.write(addr, 'B');    //Write character A
    addr++;                     //Increment address
    EEPROM.write(addr, 'C');    //Write character A
     
    String uuu = pskString;
    String www = ssidString + uuu;
    Serial.print(www);

    for (int i=0; i<www.length(); i++) { //loop upto string lenght www.length() returns length of string
      EEPROM.write(0x0F+i,www[i]);       //Write one by one with starting address of 0x0F
    }
    EEPROM.commit(); 
  } else if (ssidString == "") {
    EEPROM.begin(512);
    Serial.println("WHAT"); //Goto next line, as ESP sends some garbage when you reset it  
    Serial.print(char(EEPROM.read(addr)));    //Read from address 0x00
    addr++;                      //Increment address
    Serial.print(char(EEPROM.read(addr)));    //Read from address 0x01
    addr++;                      //Increment address
    Serial.println(char(EEPROM.read(addr)));    //Read from address 0x02
    addr++;                      //Increment address
    Serial.println(char(EEPROM.read(addr)));    //Read from address 0x03
    
    //Read string from eeprom
    String www;   
    //Here we dont know how many bytes to read it is better practice to use some terminating character
    //Lets do it manually www.circuits4you.com  total length is 20 characters
    for (int i=0; i<16; i++) {
      www = www + char(EEPROM.read(0x0F + i)); //Read one by one with starting address of 0x0F    
    } 
      
    String uuu;
    for (int i=31; i<32; i++) {
      uuu = char(EEPROM.read(0x0 + i));
    } 
    Serial.println("this");
    Serial.print(www);  //Print the text on serial monitor
    Serial.println("that");
    Serial.print(uuu);
    ssidString = www.c_str();
    pskString = uuu.c_str();
  }
}

When I do this I get the error:

incompatible types in assignment of 'const char*' to 'char [100]'

I am sending the ssidString and pskString over from an ESP12e to an ESP32-CAM via serial and got it to work by making the byte numbers 100 since it is not know what length the said and pass will be.

I am trying to get the data from EEPROM and put it into WiFi.begin(ssidString, pskString);

Can someone help with this?

score 0 · Accepted Answer · answered Nov 30 '20 at 19:27

0

Try:

String uuu = String(pskString);
String www = String(ssidString) + uuu;

Also, you shouldn't compare c strings using ==; try:

if (strcmp(ssidString, "") != 0)

and

else if(strcmp(ssidString, "") == 0)

and see what errors you get after those changes, if any.

answered Nov 30 '20 at 19:27

ocrdu

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Thanks this helped with the comparisons but I have another problem that I have to answer before I can try your other answer. – user1114881 Dec 01 '20 at 06:45
I changed my approach. I saved the ssidString and pskString with commas in between. Then I retrieved that char and split it and used the splits as the SSID and psk. Thanks for your help. – user1114881 Dec 01 '20 at 07:59

Getting error: incompatible types in assignment of 'const char*' to 'char [100]'

1 Answers1