Receive from UART on Pi - c

Question

I'm new here.
I'm trying receive data from UART which is from Xbee.
The sample code below is allow me to check the API frame.
But what I need is make these to be a useful array.
How should i make this into a complete array?
The result shows what i need but they are independent.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h> //Used for UART
#include <fcntl.h> //Used for UART
#include <termios.h> //Used for UART
int main(int argc, char const *argv[])
{
//-------------------------
//----- SETUP USART 0 -----
//-------------------------
//At bootup, pins 8 and 10 are already set to UART0_TXD, UART0_RXD (ie the alt0 function) respectively
int uart0_filestream = -1;
//OPEN THE UART
//The flags (defined in fcntl.h):
// Access modes (use 1 of these):
// O_RDONLY - Open for reading only.
// O_RDWR - Open for reading and writing.
// O_WRONLY - Open for writing only.
//
// O_NDELAY / O_NONBLOCK (same function) - Enables nonblocking mode. When set read requests on the file can return immediately with a failure status
// if there is no input immediately available (instead of blocking). Likewise, write requests can also return
// immediately with a failure status if the output can't be written immediately.
//
// O_NOCTTY - When set and path identifies a terminal device, open() shall not cause the terminal device to become the controlling terminal for the process.
uart0_filestream = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY); //Open in non blocking read/write mode
if (uart0_filestream == -1)
{
//ERROR - CAN'T OPEN SERIAL PORT
printf("Error - Unable to open UART. Ensure it is not in use by another application\n");
}
struct termios options;
tcgetattr(uart0_filestream, &options);
options.c_cflag = B9600 | CS8 | CLOCAL | CREAD; //<Set baud rate
options.c_iflag = IGNPAR;
options.c_oflag = 0;
options.c_lflag = 0;
tcflush(uart0_filestream, TCIFLUSH);
tcsetattr(uart0_filestream, TCSANOW, &options);
//----- TX BYTES -----
unsigned char tx_buffer[20];
unsigned char *p_tx_buffer;
p_tx_buffer = &tx_buffer[0];
*p_tx_buffer++ = 'H';
*p_tx_buffer++ = 'e';
*p_tx_buffer++ = 'l';
*p_tx_buffer++ = 'l';
*p_tx_buffer++ = 'o';
if (uart0_filestream != -1)
{
int count = write(uart0_filestream, &tx_buffer[0], (p_tx_buffer - &tx_buffer[0]));
//Filestream, bytes to write, number of bytes to write
if (count < 0)
{
printf("UART TX error\n");
}
}
char r[100];
while(1){
//----- CHECK FOR ANY RX BYTES -----
if (uart0_filestream != -1)
{
//printf("OK");
// Read up to 255 characters from the port if they are there
unsigned char rx_buffer[256];
int rx_length = read(uart0_filestream, (void*)rx_buffer, 255); //Filestream, buffer to store in, number of bytes to read (max)
if (rx_length < 0)
{
//An error occured (will occur if there are no bytes)
}
else if (rx_length == 0)
{
//No data waiting
}
else
{
//Bytes received
rx_buffer[rx_length] = '\0';
printf("%i bytes read : %s\n", rx_length, rx_buffer);
//printf("%d\n",rx_buffer[0]);
}
}
}
return 0;
}