我正在尝试使用 Visual Studio 2015 将 PJSUA（并尝试 PJSUA2）构建为 DLL。
该项目正确构建 .lib 文件，但将设置更改为构建 .dll 会收到有关未解析外部符号的错误消息。
我尝试使用此处描述的解决方案 >>如何在 Visual Studio 中将 PJSIP 构建为 DLL << 但我收到以下错误消息：
1>LINK : error LNK2001: unresolved external symbol _pjmedia_tonegen_create2
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_time_val_normalize
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_time_val_normalize
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_time_val_normalize
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_time_val_normalize
1>pjsua_dump.obj : error LNK2001: unresolved external symbol _pj_time_val_normalize
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_list_insert_before
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_list_insert_before
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_list_insert_before
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_list_insert_before
1>pjsua_im.obj : error LNK2001: unresolved external symbol _pj_list_insert_before
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_list_insert_after referenced in function _pj_list_push_front
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_list_merge_first referenced in function _pjsua_acc_modify
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_list_merge_last referenced in function _pjsua_acc_modify
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_list_erase referenced in function _pjsua_acc_modify
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_list_erase
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_list_erase
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_list_erase
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_list_size referenced in function _pjsua_acc_modify
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_hdr_clone referenced in function _pjsua_acc_config_dup
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pjsip_hdr_clone
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_hdr_clone
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_hdr_shallow_clone referenced in function _pjsua_acc_modify
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_hdr_print_on referenced in function _pjsip_hdr_cmp
1>pjsua_dump.obj : error LNK2001: unresolved external symbol _pjsip_hdr_print_on
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_get_status_text referenced in function _pjsua_acc_get_info
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pjsip_get_status_text
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_msg_find_hdr referenced in function _pjsua_acc_create_uas_contact
1>pjsua_im.obj : error LNK2001: unresolved external symbol _pjsip_msg_find_hdr
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pjsip_msg_find_hdr
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_msg_find_hdr_by_name referenced in function _update_service_route
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pjsip_msg_find_hdr_by_name
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pjsip_msg_find_hdr_by_name
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_generic_string_hdr_create referenced in function _pjsua_regc_init
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pjsip_generic_string_hdr_create
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_generic_string_hdr_create
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_route_hdr_create referenced in function _update_service_route
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_supported_hdr_create referenced in function _pjsua_regc_init
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_parse_uri referenced in function _pjsua_acc_modify
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pjsip_parse_uri
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_parse_uri
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pjsip_parse_uri
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_parse_hdr referenced in function _pjsua_acc_modify
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_parse_hdr
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_parser_const referenced in function _initialize_acc
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pjsip_parser_const
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_AF_UNSPEC referenced in function _pjsua_acc_get_uac_addr
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_AF_UNSPEC
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_AF_INET referenced in function _get_ip_addr_ver
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_AF_INET
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_AF_INET
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_AF_INET6 referenced in function _pjsua_acc_get_uac_addr
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_AF_INET6
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_AF_INET6
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_inet_pton referenced in function _get_ip_addr_ver
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_sockaddr_cmp referenced in function _acc_check_nat_addr
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_sockaddr_cmp
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_sockaddr_cmp
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_sockaddr_get_len referenced in function _pjsua_acc_get_uac_addr
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_sockaddr_get_len
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_sockaddr_get_len
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_sockaddr_set_port referenced in function _pjsua_acc_get_uac_addr
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_sockaddr_set_port
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_sockaddr_set_port
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_sockaddr_parse referenced in function _acc_check_nat_addr
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_gethostname referenced in function _initialize_acc
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_gethostname
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_transport_get_type_from_name referenced in function _pjsua_acc_create_uas_contact
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_transport_get_flag_from_type referenced in function _pjsua_acc_create_uas_contact
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_transport_get_flag_from_type
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_transport_get_default_port_for_type referenced in function _acc_check_nat_addr
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_transport_get_type_name referenced in function _pjsua_acc_add_local
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_tx_data_set_transport referenced in function _pjsua_acc_create_request
1>pjsua_im.obj : error LNK2001: unresolved external symbol _pjsip_tx_data_set_transport
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_transport_shutdown referenced in function _pjsua_acc_on_tp_state_changed
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_transport_shutdown
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_transport_add_ref referenced in function _pjsua_acc_modify
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_transport_dec_ref referenced in function _pjsua_acc_del
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_tpmgr_fla2_param_default referenced in function _pjsua_acc_create_uas_contact
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_tpmgr_find_local_addr2 referenced in function _pjsua_acc_create_uas_contact
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_tpmgr_send_raw referenced in function _keep_alive_timer_cb
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_endpt_schedule_timer referenced in function _keep_alive_timer_cb
1>pjsua_aud.obj : error LNK2001: unresolved external symbol _pjsip_endpt_schedule_timer
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_endpt_schedule_timer
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pjsip_endpt_schedule_timer
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_endpt_cancel_timer referenced in function _pjsua_acc_del
1>pjsua_aud.obj : error LNK2001: unresolved external symbol _pjsip_endpt_cancel_timer
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_endpt_cancel_timer
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pjsip_endpt_cancel_timer
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_endpt_get_tpmgr referenced in function _pjsua_acc_create_uas_contact
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_endpt_get_tpmgr
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_endpt_acquire_transport2 referenced in function _pjsua_acc_get_uac_addr
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_endpt_create_request referenced in function _pjsua_acc_create_request
1>pjsua_im.obj : error LNK2001: unresolved external symbol _pjsip_endpt_create_request
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_get_dest_info referenced in function _pjsua_acc_get_uac_addr
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_pool_release
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_pool_release
1>pjsua_aud.obj : error LNK2001: unresolved external symbol _pj_pool_release
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_pool_release
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_pool_release
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_pool_reset referenced in function _pjsua_acc_add
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_pool_reset
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_pool_alloc
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_pool_alloc
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_pool_alloc
1>pjsua_im.obj : error LNK2001: unresolved external symbol _pj_pool_alloc
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_pool_alloc
1>pjsua_im.obj : error LNK2001: unresolved external symbol _pj_str
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_str
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_str
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_str
1>pjsua_aud.obj : error LNK2001: unresolved external symbol _pj_str
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_str
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_str
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_strcpy referenced in function _initialize_acc
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_strdup referenced in function _pjsua_acc_config_dup
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_strdup
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_strdup
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_strdup
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_strdup_with_null
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_strdup_with_null
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_strdup_with_null
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_strdup_with_null
1>pjsua_im.obj : error LNK2001: unresolved external symbol _pj_strdup_with_null
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_strdup2 referenced in function _initialize_acc
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_strdup2_with_null referenced in function _acc_check_nat_addr
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_strcmp referenced in function _pjsua_acc_modify
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_strcmp
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_strncmp referenced in function _is_private_ip
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_stricmp
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_stricmp
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_stricmp
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_stricmp
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_stricmp
1>pjsua_im.obj : error LNK2001: unresolved external symbol _pj_stricmp
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_stricmp2
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_stricmp2
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_stricmp2
1>pjsua_aud.obj : error LNK2001: unresolved external symbol _pj_stricmp2
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_stricmp2
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_stricmp2
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_strcat referenced in function _update_regc_contact
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_strcat2 referenced in function _initialize_acc
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pj_stristr referenced in function _update_regc_contact
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_stristr
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_stristr
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_stristr
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_authorization_hdr_create referenced in function _pjsua_acc_set_registration
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_auth_clt_pref_dup referenced in function _pjsua_acc_config_dup
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_cred_info_dup referenced in function _pjsua_acc_config_dup
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_cred_info_dup
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_cred_info_cmp referenced in function _pjsua_acc_modify
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_rdata_get_tsx referenced in function _update_keep_alive
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pjsip_rdata_get_tsx
1>pjsua_im.obj : error LNK2001: unresolved external symbol _pjsip_rdata_get_tsx
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pjsip_rdata_get_tsx
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_thread_this
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_thread_this
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_thread_this
1>pjsua_aud.obj : error LNK2001: unresolved external symbol _pj_thread_this
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_thread_this
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_thread_this
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_mutex_lock
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_mutex_lock
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_mutex_lock
1>pjsua_aud.obj : error LNK2001: unresolved external symbol _pj_mutex_lock
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_mutex_lock
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_mutex_lock
1>pjsua_media.obj : error LNK2001: unresolved external symbol _pj_mutex_unlock
1>pjsua_pres.obj : error LNK2001: unresolved external symbol _pj_mutex_unlock
1>pjsua_acc.obj : error LNK2001: unresolved external symbol _pj_mutex_unlock
1>pjsua_aud.obj : error LNK2001: unresolved external symbol _pj_mutex_unlock
1>pjsua_call.obj : error LNK2001: unresolved external symbol _pj_mutex_unlock
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pj_mutex_unlock
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_create referenced in function _pjsua_regc_init
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_destroy referenced in function _pjsua_acc_del
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_get_info referenced in function _pjsua_acc_get_info
1>pjsua_core.obj : error LNK2001: unresolved external symbol _pjsip_regc_get_info
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_init referenced in function _pjsua_regc_init
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_set_reg_tsx_cb referenced in function _pjsua_regc_init
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_set_via_sent_by referenced in function _pjsua_acc_modify
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_set_delay_before_refresh referenced in function _pjsua_acc_modify
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_set_credentials referenced in function _pjsua_regc_init
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_set_prefs referenced in function _pjsua_regc_init
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_set_route_set referenced in function _pjsua_regc_init
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_set_transport referenced in function _pjsua_regc_init
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_release_transport referenced in function _pjsua_acc_on_tp_state_changed
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_add_headers referenced in function _pjsua_regc_init
1>pjsua_acc.obj : error LNK2019: unresolved external symbol _pjsip_regc_register referenced in function _pjsua_acc_set_registration
.... and much more of similar errors
有谁知道我为什么会收到这些错误？