File content as of revision 0:d5aa0b91d111:

//Author: Kuldip Maharjan
//Email : kuldipmaharjan@gmail.com
//Anyone can use this code if it helps in their projects or 
//for learning programing in mbed besides for commercial purposes

//capturing string from serial ports

#include "mbed.h"
#include "stdio.h"
#include "string.h"

char* string_capture (char* result_string);

Serial pc(USBTX, USBRX); // tx, rx
Serial s1(p9,p10);       // tx, rx
Serial s2(p28,p27);      // tx, rx

int main()
{
    char str[1024]= "";
    pc.baud(9600);
    s1.baud(9600);
    s2.baud(9600);
    while(1) {
        pc.printf("putting $ to indicate beginning of string \n");
        s1.putc('$');
        if (s2.getc() == '$') {
            pc.printf("beginning capturing string \n");
            //s1.putc('3');
            pc.printf("\n the returned string is %s",string_capture(str));
        }
        wait(2);
    }
}

char* string_capture (char* result_string)
{
    char str1[25]= "";
    do
    {
        s1.putc(pc.getc());  //here we can get character from pc terminal 
        str1[0]=s2.getc();
        strcat(result_string,str1);
        //while (!pc.readable()) {};   //gets stuck here until it get smth from pc
        wait(0.1);
    } while (str1[0] != '!');
    return result_string;
}