Add c_str free function to Boost::Format

[beojan@…]

A c_str function that returns a pointer to a new copy of the formatted string would be useful to use Boost::Format to create C-style strings.

Simply calling str(fmt).c_str() is insufficient since this returns a pointer to a temporary.

[olafvdspek@…]

Where would this new copy be stored?

[James E. King, III]

As a pattern in the standard template library that already exists, c_str() returns a pointer that is only valid for the lifetime of the object from which it was derived, and may be invalidated by mutations of that object. I see little value in encouraging the use of naked pointers here or in overriding the meaning of c_str.