How can I get a file's size in C++?

c++ filesize
Sophie Sperner picture Sophie Sperner · Apr 30, 2011 · Viewed 284.6k times · Source

Let's create a complementary question to this one. What is the most common way to get the file size in C++? Before answering, make sure it is portable (may be executed on Unix, Mac and Windows), reliable, easy to understand and without library dependencies (no boost or qt, but for instance glib is ok since it is portable library).

Answer

Spyros picture Spyros · Apr 30, 2011 
#include <fstream>

std::ifstream::pos_type filesize(const char* filename)
{
    std::ifstream in(filename, std::ifstream::ate | std::ifstream::binary);
    return in.tellg(); 
}

See http://www.cplusplus.com/doc/tutorial/files/ for more information on files in C++.

edit: this answer is not correct since tellg() does not necessarily return the right value. See http://stackoverflow.com/a/22986486/1835769

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