GCC 4.7 istream::tellg() returns -1 after reaching EOF

Question

The following code works with gcc 4.4.
But gcc 4.7 will give assertion failure.

#include 
#include 
#include 

        

Answer 1

To be precise, eofbit won't cause tellg() to return -1. But the fact that you read past EOF sets the failbit, and tellg() will return -1 if badbit or failbit are set.

The solution is to clear the status flags before calling tellg():

iss.clear();
iss.tellg();  // should work