Adafruit Fona 3g Library; How exactly does this work? - c++

Question

I am trying to send a packet to a server over 3g and TCP connection. Below is a link to the .cpp and .h file I have found:
https://os.mbed.com/users/Nels885/code/Adafruit_FONA_3G/
More specifically, I am really confused on how TCPSend works under the Adafruit_FONA_3G class. I am trying to implement it but my code seems to get stuck at packet[0] = 0; under function bool Adafruit_FONA_3G::TCPsend(char *packet).
I have tried commenting out packet[0] = 0; and the code runs all the way through. I have also tried initializing char* packet[32]; before packet[0] = 0; and the code runs all the way through. I am assuming the function is not detecting the packet input.
Here is the specific function from the .cpp file:
bool Adafruit_FONA_3G::TCPsend(char *packet)
{
if (strlen(packet) > 0)
{
mySerial.printf("%s", packet);
//mySerial.printf("%s\r\n", packet);
readline();
packet[0] = 0;
return true;
}
else
return false;
}
Here is my main code:
#include "mbed.h"
#include "Adafruit_FONA.h"
#define FONA_RST D4
#define FONA_TX D1
#define FONA_RX D0
#define FONA_RI D7 //not used
char replybuffer[255];
Adafruit_FONA_3G fona(FONA_TX, FONA_RX, FONA_RST, FONA_RI);
Serial pc(USBTX, USBRX);
int main()
{
fona.TCPinitialize();
char Timeout[21];
fona.getTCPtimeout(Timeout);
char * Server = "52.14.99.26";
uint16_t Port = 10001;
fona.TCPconnect(Server,Port);
char *Packet = "Pick Up %";
fona.TCPsend(Packet);
fona.TCPclose();
}

Answer 1

Adafruit_FONA_3G::TCPsend() assumes that you pass it a writable buffer. You're passing a read-only buffer. So, replace
char *Packet = "Pick Up %";
with
char Packet[] = "Pick Up %";
The problem is really that your compiler allows you to initialize writable pointers with read-only values. This is a shortcoming of your compiler.