semantic-unmatched-syntax-hook

semantic-unmatched-syntax-hook is a variable defined in `semantic.el'.
Its value is

nil

• This variable may be risky if used as a file-local variable.

Documentation:
Hooks run when Semantic detects syntax not matched in a grammar.
Each individual piece of syntax (such as a symbol or punctuation
character) is called with this hook when it doesn't match in the
grammar, and multiple unmatched syntax elements are not grouped
together. Each hook is called with one argument, which is a list
of syntax tokens created by the semantic lexer. Use the functions
`semantic-lex-token-start', `semantic-lex-token-end' and
`semantic-lex-token-text' to get information about these tokens.
The current buffer is the buffer these tokens are derived from.