do_sub_field(a_time, hours, extra, 24, sub_days); 
do_sub_time_field(a_time, hours, extra, 24, sub_days); 
sub_hours(ha_time_t *a_time, int extra) {	if(extra < 0) {		add_hours(a_time, -extra);	} else {		do_sub_field(a_time, hours, extra, 24, sub_days);	}}
8182	/local/tlutelli/issta_data/temp/c/2005_temp/2005/8182/bcfff519cc4d290a5980ee13c56b39315c2dcba1/iso8601_fields.c/buggy/lib/crm/common/iso8601_fields.c