[syslog-ng] Special characters in syslogng filters

Hello   If the filter specified in syslog-ng.conf contains the ( character or ) character, then is it correct to prefix them with \\.   For example, if I need to filter a syslog containing the string (abcd)   then in syslog-ng.conf, I would need to specify the filter as \\(abcd\\)   Could someone confirm, if this is the correct way of specifying the filter, please ?   If not, please let me know the correct way of specifying the filter.   Thanks in advance for your help.