Making a product display progress information during install

[mfyvie]

I'm having a bit of trouble with a product I'm writing.

This product imports a large database, and while it is installing I'd like it to report progress as it does every 1000 records or so. If the import file isn't found, then it should report this as well, preferably with the option to wait for the user to click ok before the screen changes.

The problem is that if I use echo 'some string'; like many of the other products do, this output is gathered up and only displayed when the mod has finished installing, and then is visible only for a second or so before disappearing. I've also tried using stdout, but no luck there either.

I've tried using some of the print_cp functions, but they don't appear to work inside the installer. I did however manage to use the print_dots_start, but wasn't able to make the dots move or print more than one line (i had to use separate sets of dots).

What is the preferred way of providing useful information to the admin during the installation of a product?

Follow up question for extra bonus points - if someone is replacing the same product and the same version number, the installation routine won't run unless they have uninstalled the product first. Is there a way to force all or a portion of the installating routine to run, even if the version numbers stay then same during a re-installation (i.e. no uninstall has taken place).