How can I format the boost path object without quotes?

Question

Here is my code:

fs::path datadir = ...;
std::string dataDirOption((boost::format("--datadir=%1%") % datadir).str());

For datadir=="c:/db" I get dataDirOption=="--datadir=\"c:/db\"", instead of "--datadir=c:/db"

Is it possible to tell boost::filesystem::path to skip the quotes when being formatted?

Now, I know I can substitute datadir.string() for datadir and get rid of the quotes in this way, but I am wondering whether I can do so without the extra string.

Thanks.

Answer 1

No it is not, is is a bug files on the boost framework version 1.47.0 which has not yet been given a milestone on when to be fixed.

The workaround however is:

std::cout << path("/foo/bar.txt").filename().string()

Answer 2

The % operator for format uses the << stream-insertion operator for user-defined types, and the documentation tells us it's effectively the following for path:

os << boost::io::quoted(p.string<std::basic_string<Char>>(), static_cast<Char>('&'));

To leave out the quotes, you need to pass something different to the format object, such as the output of the string method as you've already discovered.