C++ Coding Help/Support Wanted (modem required)

I have a command console modem utility that lets me send commands to a modem and register the response, plus I have a function 'getavar' that opens a text file, searches for a marker, then collects to a memory buffer named 'thestring' ... the string ... immediately following the marker. I want some minor modification done to the getavar function and I ultimately want to build my modem program with a link to a new file named mytools.cpp.