I need to store an ipaddress in the eeprom. how can i save the ip address as char array or similar. i want to get the ipaddress from udp.remoteipaddres() then save it in the eeprom
Here's a function to do it:
// convert IPAddress to char array and put it in the passed buffer
void IPtoa(const IPAddress & IP, char IPcharBuffer[]) {
#if defined(__ARDUINO_X86__)
sprintf (IPcharBuffer, "%u", IP[0]);
#else //defined(__ARDUINO_X86__)
utoa(IP[0], IPcharBuffer, 10); //convert the first octet
#endif //defined(__ARDUINO_X86__)
for (byte octetCount = 1; octetCount < 4; octetCount++) { //convert the other 3 octets
strcat(IPcharBuffer, ".");
char octetChar[3 + 1]; //3 digit byte + null terminator
#if defined(__ARDUINO_X86__)
sprintf (octetChar, "%u", IP[octetCount]);
#else //defined(__ARDUINO_X86__)
utoa(IP[octetCount], octetChar, 10); //convert the octet
#endif //defined(__ARDUINO_X86__)
strcat(IPcharBuffer, octetChar);
}
}
pert:
Here's a function to do it:// convert IPAddress to char array and put it in the passed buffer
void IPtoa(const IPAddress & IP, char IPcharBuffer[]) {
#if defined(ARDUINO_X86)
sprintf (IPcharBuffer, "%u", IP[0]);
#else //defined(ARDUINO_X86)
utoa(IP[0], IPcharBuffer, 10); //convert the first octet
#endif //defined(ARDUINO_X86)
for (byte octetCount = 1; octetCount < 4; octetCount++) { //convert the other 3 octets
strcat(IPcharBuffer, ".");
char octetChar[3 + 1]; //3 digit byte + null terminator
#if defined(ARDUINO_X86)
sprintf (octetChar, "%u", IP[octetCount]);
#else //defined(ARDUINO_X86)
utoa(IP[octetCount], octetChar, 10); //convert the octet
#endif //defined(ARDUINO_X86)
strcat(IPcharBuffer, octetChar);
}
}
i dont even know how to begin to comprehend that. i see sprintf writing into ipcahrbuffer. but how do i use this function
You need to create a buffer of the appropriate size, then pass the IPAddress and the buffer to the function:
byte IPAddressLengthMax = 3 + 1 + 3 + 1 + 3 + 1 + 3; //4 x octet + 3 x dot
char IPstringBuffer[IPAddressLengthMax + 1]; // Make sure to leave room in the buffer for the terminator
...
IPtoa(someIPAddress, IPstringBuffer);
After the IPtoa() function returns, IPstringBuffer will contain the string representation of someIPAddress.
pert:
You need to create a buffer of the appropriate size, then pass the IPAddress and the buffer to the function:byte IPAddressLengthMax = 3 + 1 + 3 + 1 + 3 + 1 + 3; //4 x octet + 3 x dot
char IPstringBuffer[IPAddressLengthMax + 1]; // Make sure to leave room in the buffer for the terminator
...
IPtoa(someIPAddress, IPstringBuffer);
After the IPtoa() function returns, IPstringBuffer will contain the string representation of someIPAddress.
Hi thanks. im trying to understand this. my compiler complains about declaring void function.
void IPtoa(someIPAddress, IPstringBuffer) {
byte IPAddressLengthMax = 3 + 1 + 3 + 1 + 3 + 1 + 3; //4 x octet + 3 x dot
char IPstringBuffer[IPAddressLengthMax + 1]; // Make sure to leave room in the buffer for the terminator
return
}
my compiler complains about declaring void function
You misunderstand. @pert has shown you how to use the function he provided in his previous reply.
You don't declare a new function, you just call IPtoa() as he has shown.
notsolowki:
Hi thanks. im trying to understand this. my compiler complains about declaring void function.void IPtoa(someIPAddress, IPstringBuffer) {
byte IPAddressLengthMax = 3 + 1 + 3 + 1 + 3 + 1 + 3; //4 x octet + 3 x dot
char IPstringBuffer[IPAddressLengthMax + 1]; // Make sure to leave room in the buffer for the terminator
return
}
return without a semi-colon.
cattledog:
You misunderstand. @pert has shown you how to use the function he provided in his previous reply.You don't declare a new function, you just call IPtoa() as he has shown.
I have missunderstood.
when i try to compile this i get error
array bound is not an integer constant before ']' token
#include <EEPROM.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
void IPtoa(const IPAddress & IP, char IPcharBuffer[]) {
#if defined(__ARDUINO_X86__)
sprintf (IPcharBuffer, "%u", IP[0]);
#else //defined(__ARDUINO_X86__)
utoa(IP[0], IPcharBuffer, 10); //convert the first octet
#endif //defined(__ARDUINO_X86__)
for (byte octetCount = 1; octetCount < 4; octetCount++) { //convert the other 3 octets
strcat(IPcharBuffer, ".");
char octetChar[3 + 1]; //3 digit byte + null terminator
#if defined(__ARDUINO_X86__)
sprintf (octetChar, "%u", IP[octetCount]);
#else //defined(__ARDUINO_X86__)
utoa(IP[octetCount], octetChar, 10); //convert the octet
#endif //defined(__ARDUINO_X86__)
strcat(IPcharBuffer, octetChar);
}
}
byte IPAddressLengthMax = 3 + 1 + 3 + 1 + 3 + 1 + 3; //4 x octet + 3 x dot
char IPstringBuffer[IPAddressLengthMax + 1]; // Make sure to leave room in the buffer for the terminator
void setup() {
// put your setup code here, to run once:
}
void loop() {
// put your main code here, to run repeatedly:
IPtoa(someIPAddress, IPstringBuffer);
}
Nope im still getting ⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮ from the serial.println of _EEPROM.UV_IP after IPtoa(WiFi.localIP(), _EEPROM.UV_IP);
will someone explain the behaviour. why when i print _EEPROM.IV_IP after reboot it prints all question marks.
even though its printing all question marks i can still use it as an ipaddress with udp.beginPacket.
wow it was so easy to do,
String str = Udp.remoteIP().toString();
str.toCharArray(_EEPROM.UV_IP, 15);
how come no one said this
Because you don't give people the time to react 
And you can't store Strings in EEPROM. It will store the pointer to the actual data but not the actual data itself. After a reboot of your board, the data where that pointer points to might have been moved (e.g. when you change your sketch) or the data might have been wiped.