图片：
程序中定义的API：
Function Boolean CloseHandle(ulong hObject ) Library "kernel32.dll"
FUNCTION boolean ReadFile(ulong fhand, ref string lpbuffer, ulong numbyte, ref ulong bytesread, ulong lpover) LIBRARY "kernel32.dll"
FUNCTION ulong CreateFileA(ref string fname, ulong f_access, ulong f_share, ulong f_sec, ulong f_create, ulong f_flag, ulong f_attrib) LIBRARY "kernel32.dll"
Function Boolean WriteFile(uLong handle,ref string lpbuffer,ulong numbytes, ref ulong bytesread, ulong lpOverLaped) Library "Kernel32.dll"
Function Boolean GetCommProperties(ulong hFile,ref COMMPROP lpCommProp ) Library "Kernel32.dll"
Function Boolean BuildCommDCBA(ref string lpDef,ref DCB lpDCB ) Library "Kernel32.dll"
Function Boolean SetCommState(ulong hCommDev,ref DCB lpdcb ) Library "Kernel32.dll"
Function Boolean GetCommState(ulong hCommDev,ref DCB lpdcb ) Library "Kernel32.dll"
Function ulong GetLastError() Library "Kernel32.dll"
Function Boolean SetCommTimeouts(ulong hCommDev, ref COMMTIMEOUTS lpctmo ) Library "Kernel32.dll"
Function Boolean PurgeComm(ulong hCommDev, ulong fdwAction ) Library "Kernel32.dll"
