seekg cannot handle file of 4294967295 bytes properly

I found that in VS2010, seekg function does not work properly when file of exactly 4294967295 bytes is opened. I'm using simple code: ``` #include <iostream> #include <fstream> using namespace std; int _tmain(int argc, _TCHAR* argv[]) { std::ifstream file; // cmd: fsutil file createnew tmp.txt 4294967295 file.open(L"c:/tmp.txt", ifstream::in | ifstream::binary); if(!file.is_open()) return -1; file.seekg(0, std::ios::end); auto state = file.rdstate(); // this condition shoots only when size of the file is equal to 4294967295 if((state & ifstream::failbit)==ifstream::failbit) { std::cout << "seekg failed"; } // after seekg failed, tellg returns 0 std::streampos endPos = file.tellg(); return 0; } ``` Same code with files of 4294967294 and 4294967296 is working without any problems. Does someone know a solution to this problem? Update: It looks like that problem lies here: ``` template<class _Statetype> class fpos { __CLR_OR_THIS_CALL operator streamoff() const { // return offset return ((streamoff)(_Myoff + _FPOSOFF(_Fpos))); } } ``` exactly at ``` _FPOSOFF(_Fpos) ``` where ``` #define _FPOSOFF(fp) ((long)(fp)) ``` So it takes 4294967295 and converts it to -1 ! In other words speaking, such code will fail ``` //returns -1, even if sizeof(fpos_t)=8 fpos_t pos = _FPOSOFF(4294967295); ``` _Myoff, _Fpos, streamoffset are 64bit Why they do this conversion if all types are 64 bit!? I have no idea ))