The definition of the behaviour of pos in http://www.mediawiki.org/wiki/Extension:StringFunctions is:

"If the search term is found, the return value is a zero-based integer of the first position within the string. If the search term is not found, the function returns an empty string."

The current revision SVN 51470 of String functions 1.2.0 returns -1 if the string is not found.

Wikis which had string functions installed will currently no longer display their templates correctly.

Version: unspecified
Severity: critical