smarmiroli - 2018-09-27

Good morning,
how can i create an user defined attribute?
To do this ,onn codesys online help, there is an enigmatic assertion :
{define <identifier> <string>}</string></identifier>
and the relative
{undefine <identifier> }</identifier>
to delete it.
If i wont to define the attribute 'foo' , how can i interpretate this help suggestion?

Thank you
P.S. here the link on the page:
https://help.codesys.com/api-content/2/ ... 0e015d431a m