Im having trouble calling an input file stream from inside a function and was hoping if anyone can help me with a solution. Im compiling with MSVC++ 8.0. Below is a detailed description of the problem: The input file that Im trying to read is pt03-test-1.txt. Its just a text file with 2 integer values in a single column: 24 35 the path to the file is : /tao/data/pt03-test-1.txt The following code works: #include <iostream> #include <vector> #include <fstream> #include <boost/filesystem/operations.hpp> #include <boost/filesystem/fstream.hpp> int main() { boost::filesystem::ifstream inputDataStream("/tao/data/pt03-test-1.txt"); int mobilityIndexMarker = 0; inputDataStream >> mobilityIndexMarker; std::cout << mobilityIndexMarker << std::endl; return (0); }; Encapsulating the lines in main in a separate function breaks the code: #include <iostream> #include <vector> #include <fstream> #include <boost/filesystem/operations.hpp> #include <boost/filesystem/fstream.hpp> boost::filesystem::ifstream inputDataStream; //declaration of inputDataStream void trialOnsetWrite() { int mobilityIndexMarker = 0; inputDataStream >> mobilityIndexMarker; std::cout << mobilityIndexMarker << std::endl; }; int main() { boost::filesystem::ifstream inputDataStream("/tao/data/pt03-test-1.txt"); trialOnsetWrite(); return (0); }; Very Very Appreciative, Patrick