Question

This is a reverse engineering question.

On Windows 7 with a binary compiled using Microsoft Visual C++ 2008, when std::cout is called. Internally, what API is used to write the data? WriteFile, fwrite, ConsoleOut? I am aiming to set a breakpoint on std::cout where no source or debugging symbols are available.

Answer 1

I believe it’ll end up using WriteFile. It you compile a simple hello world:

#include <iostream>
int main(int argc, char **argv)
{
  std::cout << "Hello" << std::endl;
  return (0);
}

…and then do dumpbin /imports hello.exe, you get a list of the external functions it uses, you’ll find that it imports both WriteFile and WriteConsoleW, but if memory serves, the latter is only used for printing some standard library error messages, not for standard output.