CORRUPT HEAP

[quentho]

Hello,

i would like to put my serial char result inside char* with concatenation function.
But i have a 2 problem problemes :
CORRUPT HEAP: Bad tail
CORRUPT HEAP: multi_heap.c:432
i think it's overload but i initialize my pointer with 15 octets and normaly it's enought.

Code: [Select all] [Expand/Collapse]

1. void Wisol::getID()
2. {
3.   printf("getID");
4.   char * data=(char *) malloc(15);
5.   char  receive;
6.   *(data)='\0';
7.   Serial2.begin(9600, SERIAL_8N1, RXPin, TXPin);
8.   Serial2.println("AT$I=10");
9. delay(1000);
10.   while (Serial2.available()) {
11.    //Serial.println(char(Serial2.read()));
12.    delay(100);
13.    receive= Serial2.read();
14.    printf("data: %c \n",receive);
15.    strcat( data, &receive );
16.   }
17.     free(data);
18. }

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X

[ESP_Angus]

You can't use "strcat()" with a single char, it takes a null-terminated string. If the byte after "receive" in the RAM is a zero, it will work as expected. If the byte is anything else, it will keep concatenating those bytes to the string until it sees a zero. This could be a lot more than 15 bytes!

[quentho]

I don't understand because i have set the termined zero terminal with this line : *(data+1)='\0';. It's working but the probleme is when i free my pointer.
I show you the new code with the same result

[ESP_Sprite]

Now you're allocating only one char for data and data_int, and you're writing more than one char to it. (The zero terminators to start with, and the strcat also overwrites the end of data).

[quentho]

I increased the size of my pointers with new char [15], I have the right concatenation but I still have a problem with my memory free call CORRUPT HEAP tail.

[ESP_Sprite]

How do you get to 15? According to the log of your program, data contains '7OK\r\nOK\r\nOK\r\n00352643\r\n' (with \r\n being carriage return / newline, which won't show up as individual characters on your terminal) which is way longer than 15.