C++ readlink wrapper

readlink.cpp

// This is C++11-only because it assumes that std::strings can
// be accessed and mutated as a contiguous sequence of chars.
std::string	sys::readlink (const char* pathname)
{
	std::string		buffer(64, '\0');
	ssize_t			len;

	while ((len = ::readlink(pathname, &buffer[0], buffer.size())) == static_cast<ssize_t>(buffer.size())) {
		// buffer may have been truncated - grow and try again
		buffer.resize(buffer.size() * 2);
	}

	if (len == -1) {
		throw error("readlink", errno);
	}

	buffer.resize(len);

	return buffer;
}