Incompatible with smtp.module (redeclared function)

Don't install both modules together. They both need the same Drupal function to work.

I ran into the same problem with the mimemail module.

I know that it's "not returnpath's fault" but it would be nice if rather than a fatal error the module would do a check if the function_exists('user_mail_wrapper') before declaring it and if it exists, just do a drupal_set_message warning about the incompatibility. http://php.net/function_exists

Tentatively setting back to active as a feature request in light of this new proposal, but feel free to won't fix again if you feel this is unecessary.

Getting this error message after enabling returnpath.module (Return-Path), while smtp.module (SMTP Authentication Support) is enabled:
Fatal error: Cannot redeclare drupal_mail_wrapper() (previously declared in {path}/modules/smtp/smtp.module:236) in {path}/modules/returnpath/returnpath.module on line 52
using:
returnpath-6.x-1.0.tar.gz
smtp-6.x-1.0-beta3.tar.gz
PHPMailer_v5.0.0.tar.gz

I have also submitted this issue for the SMTP Authentication Support module:
http://drupal.org/node/597986

It turns out (http://drupal.org/node/597986) that the SMTP Authentication Support module DOES correctly handle the return path email headers. Therefore, activation of the returnpath.module (Return-Path) should be disabled/ disallowed, whenever the 'SMTP Authentication Support' module is activated.

How do you disallow/disable a module if another module is active?