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Lwm2m对应的client的cmake如下：#从这里可以build的是Lwm2m的clientproject (lwm2mclient C)#关掉DTSoption(DTLS "Enable DTLS" OFF)include(${CMAKE_CURRENT_LIST_DIR}/../../core/wakaama.cmake) include(${CMAKE_CURRENT_LIST_DIR}/../shared/shared.cmake)add_definitions(-DLWM2M_CLIENT_MODE -DLWM2M_BOOTSTRAP -DLWM2M_SUPPORT_JSON) add_definitions(${SHARED_DEFINITIONS} ${WAKAAMA_DEFINITIONS})include_directories (${WAKAAMA_SOURCES_DIR} ${SHARED_INCLUDE_DIRS})#client 包含的所有头文件如下：SET(SOURCES ${CMAKE_CURRENT_LIST_DIR}/lwm2mclient.c    ${CMAKE_CURRENT_LIST_DIR}/lwm2mclient.h    ${CMAKE_CURRENT_LIST_DIR}/system_api.c    ${CMAKE_CURRENT_LIST_DIR}/object_security.c    ${CMAKE_CURRENT_LIST_DIR}/object_server.c    ${CMAKE_CURRENT_LIST_DIR}/object_device.c    ${CMAKE_CURRENT_LIST_DIR}/object_firmware.c    ${CMAKE_CURRENT_LIST_DIR}/object_location.c    ${CMAKE_CURRENT_LIST_DIR}/object_connectivity_moni.c    ${CMAKE_CURRENT_LIST_DIR}/object_connectivity_stat.c    ${CMAKE_CURRENT_LIST_DIR}/object_access_control.c    ${CMAKE_CURRENT_LIST_DIR}/test_object.c    )#这个工程是编译成一个可执行的文件add_executable(${PROJECT_NAME} ${SOURCES} ${WAKAAMA_SOURCES} ${SHARED_SOURCES})从上面的分析可知，client的入口函数在lwm2mclient.c 中的main函数，其处理流程和server端的流程基本类似，都是建立一个socket，然后在一个死循环中监听socket通信，处理package有一点不同是在client的main函数中注册了很多object的处理函数    objArray[1] = get_server_object(serverId, "U", lifetime, false);    if (NULL == objArray[1])    {        fprintf(stderr, "Failed to create server object\r\n");        return -1;    }这里的OBJ_COUNT 等于9 也就是说最多支持9中object#define OBJ_COUNT 9lwm2m_object_t * objArray[OBJ_COUNT];我们举个例子看看object 都干了啥lwm2m_object_t * get_server_object(int serverId,                                   const char* binding,                                   int lifetime,                                   bool storing){    lwm2m_object_t * serverObj;#首先申请一个结构体    serverObj = (lwm2m_object_t *)lwm2m_malloc(sizeof(lwm2m_object_t));    if (NULL != serverObj)    {        server_instance_t * serverInstance;        memset(serverObj, 0, sizeof(lwm2m_object_t));        serverObj->objID = 1;        // Manually create an hardcoded server        serverInstance = (server_instance_t *)lwm2m_malloc(sizeof(server_instance_t));        if (NULL == serverInstance)        {            lwm2m_free(serverObj);            return NULL;        }#初始化这个结构体成员变量        memset(serverInstance, 0, sizeof(server_instance_t));        serverInstance->instanceId = 0;        serverInstance->shortServerId = serverId;        serverInstance->lifetime = lifetime;        serverInstance->storing = storing;        memcpy (serverInstance->binding, binding, strlen(binding)+1);        serverObj->instanceList = LWM2M_LIST_ADD(serverObj->instanceList, serverInstance);#重点是这里的几个回调函数        serverObj->readFunc = prv_server_read;        serverObj->discoverFunc = prv_server_discover;        serverObj->writeFunc = prv_server_write;        serverObj->createFunc = prv_server_create;        serverObj->deleteFunc = prv_server_delete;        serverObj->executeFunc = prv_server_execute;    }    return serverObj;}可见所以的object关键就是一组不动听的read/writer/create等回调函数这样当clinet处理package的时候就会调用lwm2m_handle_packet->handle_request->handle_request->object_checkReadable->observe_setParameters->object_checkReadableuint8_t object_checkReadable(lwm2m_context_t * contextP,                             lwm2m_uri_t * uriP,                             lwm2m_attributes_t * attrP){#最终读取每个object注册时候的回调函数    result = targetP->readFunc(uriP->instanceId, &size, &dataP, targetP);    if (result == COAP_205_CONTENT)    {        if (attrP->toSet & ATTR_FLAG_NUMERIC)        {            switch (dataP->type)            {                case LWM2M_TYPE_INTEGER:                case LWM2M_TYPE_FLOAT:                    break;                default:                    result = COAP_405_METHOD_NOT_ALLOWED;            }        }    }}

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