boot filesystem error when copy-overwrite-the file to itself

[hoangtrongminhtuan@…]

I'm running RedHat. I tried to copy, and overwrite if existing file 'a' to itself.

namespace fs=boost::filesystem; fs::copyfile('a', 'a', fs::copy_option::overwrite_if_exist);

This clear the content of 'a', and giving me an empty file.

[anonymous]

Let me make clear that I tried one without the dot '.' and the one with the dot

fs::copyfile('RESULT/a', './RESULT/a', fs::copy_option::overwrite_if_exist);