我在编译.CU文件时候，老是出现一些警告错误，请问是什么意思啊？
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(92) : warning C4311: ‘reinterpret_cast’ : pointer truncation from ‘void *’ to ‘LONG’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(92) : warning C4312: ‘reinterpret_cast’ : conversion from ‘LONG’ to ‘void *’ of greater size
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(945) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(945) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(945) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(945) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(953) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(953) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(1145) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(1145) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(1145) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(1145) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(1153) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’
1>D:\Program Files\Microsoft Visual Studio 9.0\VC\ATLMFC\INCLUDE\atlconv.h(1153) : warning C4311: ‘type cast’ : pointer truncation from 'volatile const char *__w64 ’ to ‘unsigned int’