How to verify if a plugin is installed ?

[didou038]

Hi all !

i'm working on a template, and I wish to verify if a plugin is installed to activate or not a template option.

For example, if the plugin "I18N_Search" is installed then the search module can be activate, otherwise, it's indicated that the plugin "I18N_Search" must be installed to activate this option.

Is it possible ? If yes, can you tell me the way to follow ?

I know, I have really weird questions ^^

Thanks for your help