1 结构体指针，主机的一些综合参数
            //dbcache.h 
            typedef struct
            {
                DC_HOST            host;
                DC_INTERFACE        interface;
                zbx_uint64_t        itemid;
                zbx_uint64_t        lastlogsize;
                zbx_uint64_t        valuemapid;
                unsigned char        type;
                unsigned char        value_type;
                unsigned char        state;
                unsigned char        snmpv3_securitylevel;
                unsigned char        authtype;
                unsigned char        flags;
                unsigned char        snmpv3_authprotocol;
                unsigned char        snmpv3_privprotocol;
                unsigned char        inventory_link;
                unsigned char        status;
                unsigned char        history;
                unsigned char        trends;
                unsigned char        follow_redirects;
                unsigned char        post_type;
                unsigned char        retrieve_mode;
                unsigned char        request_method;
                unsigned char        output_format;
                unsigned char        verify_peer;
                unsigned char        verify_host;
                unsigned char        allow_traps;
                char            key_orig[ITEM_KEY_LEN * ZBX_MAX_BYTES_IN_UTF8_CHAR + 1], *key;
                char            *units;
                char            *delay;
                int            history_sec;
                int            nextcheck;
                int            lastclock;
                int            mtime;
                char            trapper_hosts[ITEM_TRAPPER_HOSTS_LEN_MAX];
                char            logtimefmt[ITEM_LOGTIMEFMT_LEN_MAX];
                char            snmp_community_orig[ITEM_SNMP_COMMUNITY_LEN_MAX], *snmp_community;
                char            snmp_oid_orig[ITEM_SNMP_OID_LEN_MAX], *snmp_oid;
                char            snmpv3_securityname_orig[ITEM_SNMPV3_SECURITYNAME_LEN_MAX], *snmpv3_securityname;
                char            snmpv3_authpassphrase_orig[ITEM_SNMPV3_AUTHPASSPHRASE_LEN_MAX], *snmpv3_authpassphrase;
                char            snmpv3_privpassphrase_orig[ITEM_SNMPV3_PRIVPASSPHRASE_LEN_MAX], *snmpv3_privpassphrase;
                char            ipmi_sensor[ITEM_IPMI_SENSOR_LEN_MAX];
                char            *params;
                char            username_orig[ITEM_USERNAME_LEN_MAX], *username;
                char            publickey_orig[ITEM_PUBLICKEY_LEN_MAX], *publickey;
                char            privatekey_orig[ITEM_PRIVATEKEY_LEN_MAX], *privatekey;
                char            password_orig[ITEM_PASSWORD_LEN_MAX], *password;
                char            snmpv3_contextname_orig[ITEM_SNMPV3_CONTEXTNAME_LEN_MAX], *snmpv3_contextname;
                char            jmx_endpoint_orig[ITEM_JMX_ENDPOINT_LEN_MAX], *jmx_endpoint;
                char            timeout_orig[ITEM_TIMEOUT_LEN_MAX], *timeout;
                char            url_orig[ITEM_URL_LEN_MAX], *url;
                char            query_fields_orig[ITEM_QUERY_FIELDS_LEN_MAX], *query_fields;
                char            *posts;
                char            status_codes_orig[ITEM_STATUS_CODES_LEN_MAX], *status_codes;
                char            http_proxy_orig[ITEM_HTTP_PROXY_LEN_MAX], *http_proxy;
                char            *headers;
                char            ssl_cert_file_orig[ITEM_SSL_CERT_FILE_LEN_MAX], *ssl_cert_file;
                char            ssl_key_file_orig[ITEM_SSL_KEY_FILE_LEN_MAX], *ssl_key_file;
                char            ssl_key_password_orig[ITEM_SSL_KEY_PASSWORD_LEN_MAX], *ssl_key_password;
                char            *error;
            }
            DC_ITEM;
        2 结构体指针
            //common.h
            typedef struct
            {
                int    sec;    /* seconds */
                int    ns;    /* nanoseconds */
            }
            zbx_timespec_t;
            
        3 错误信息

        //db.h
        typedef struct
        {
            /* flags specifying which fields are set, see ZBX_FLAGS_AGENT_STATUS_* defines */
            unsigned char    flags;

            /* agent availability fields */
            unsigned char    available;
            char        *error;
            int        errors_from;
            int        disable_until;
        }
        zbx_agent_availability_t;

        typedef struct
        {
            zbx_uint64_t            hostid;

            zbx_agent_availability_t    agents[ZBX_AGENT_MAX];         //这里的ZBX_AGENT_MAX 为4 ，分别代表ZABBIX, SNMP, IPMI, JMX4种类型
        }
        zbx_host_availability_t;