int _stdcall get_properties(int camera, const char * content, unsigned int content_len, char** result, unsigned int * result_len, DWORD wait_time);
camera:[in]，The camera's handle which is from new_camera
content:[in]，One or more properties which want to get
content_len:[in]，The properties content's length
result:[out]，The properties result
result_len:[out]，The result's length
wait_time:[in]，The time waiting for repone, millisecond
Return ERROR_OK if success，else refer to the definition of error number
Gets the camera properties.
Before calling this function, should first ensure the connection of camera with the
specified has been established, or the operation will fail.
The result of the operation through the GET_PROPERTIES_RESULT event notification user.
The content parameter is used to specify the attribute name query, if NULL,
Show to query all have permission to query attributes. The format of the content parameter
is composed of one or more strings, Each string is composed of attribute name to query,
between each string '\0' separated by.
The content_len parameter value is equal to the length of all the data of content, including each end of the string '\0'.
For example:
Content = "firmware_ver\0webui_ver\0ptz\0"; (Note: Here "" does not mean that the content of C string, just represent the distribution in memory)
Content_len 27.
As for the specific attributes of the camera please refer to the relevant CGI application guide.