[boost] Re: How are boost/mpl/aux_/preprocessed files generated?

From: Jonathan Turkanis (technews_at_[hidden])
Date: 2005-06-10 17:09:14

Larry Evans wrote:

>> Why would you expect to find 'template?'
>>
> Because I was under the mistaken assumption that the python code,
> somehow was the only step in generating the files.  Now I'm guessing
> that the preprocessing done by preprocess.cmd does most of the work
> and the python code does some minor adjustments.  I'm guessing that
> the only reason for the python code is to save the user from having to
> regenerating the code with the preprocessor each time he compiles.
> IOW, the code in aux_/preprocessed is sort-of a cache or somewhat
> like a pre-compiled header.

The point of preprocessing certain headers is just to save the compiler from
having to preprocess them on each compilation. The main work is done by the
preprocessor itself. As I understand it, the Python script just makes the
preprocessed code compact and readable.

If you look at some preprocessed code you'll often see long sequences of blank
lines. Also, the ouput of Boost.PP is generally not nicely formatted.

Jonathan