the expected token.
a string describing how the scanner's user refers to identifiers (NULL defaults to "identifier"). This is used if expected_token is G_TOKEN_IDENTIFIER or G_TOKEN_IDENTIFIER_NULL.
a string describing how the scanner's user refers to symbols (NULL defaults to "symbol"). This is used if expected_token is G_TOKEN_SYMBOL or any token value greater than G_TOKEN_LAST.
the name of the symbol, if the scanner's current token is a symbol.
a message string to output at the end of the warning/error, or NULL.
if TRUE it is output as an error. If FALSE it is output as a warning.
Outputs a message through the scanner's msg_handler, resulting from an unexpected token in the input stream. Note that you should not call g_scanner_peek_next_token() followed by g_scanner_unexp_token() without an intermediate call to g_scanner_get_next_token(), as g_scanner_unexp_token() evaluates the scanner's current token (not the peeked token) to construct part of the message.