各位达人：spcomm为什么打不开大于等于10的串口？ ( 积分: 100 )

如果把comm1.CommName:='com10'就会出现“Error opening serial port”
附上spcomm这段打开串口的程序：
procedure TComm.StartComm;
var
hNewCommFile: THandle;
begin
// Are we already doing comm?
if (hCommFile <> 0) then
raise ECommsError.Create( 'This serial port already opened' );

hNewCommFile := CreateFile( PChar(FCommName),
GENERIC_READ or GENERIC_WRITE,
0, {not shared}
nil, {no security ??}
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL or FILE_FLAG_OVERLAPPED,
0 {template} );

if hNewCommFile = INVALID_HANDLE_VALUE then
raise ECommsError.Create( 'Error opening serial port' );//[red]就是这个地方[/red]

// Is this a valid comm handle?
if GetFileType( hNewCommFile ) <> FILE_TYPE_CHAR then
begin
CloseHandle( hNewCommFile );
raise ECommsError.Create( 'File handle is not a comm handle ' )
end;

if not SetupComm( hNewCommFile, 4096, 4096 ) then
begin
CloseHandle( hCommFile );
raise ECommsError.Create( 'Cannot setup comm buffer' )
end;

// It is ok to continue.

hCommFile := hNewCommFile;

// purge any information in the buffer

PurgeComm( hCommFile, PURGE_TXABORT or PURGE_RXABORT or
PURGE_TXCLEAR or PURGE_RXCLEAR ) ;
FSendDataEmpty := True;

// Setting the time-out value
_SetCommTimeout;

// Querying then setting the comm port configurations.
_SetCommState;

// Create the event that will signal the threads to close.
hCloseEvent := CreateEvent( nil, True, False, nil );

if hCloseEvent = 0 then
begin
CloseHandle( hCommFile );
hCommFile := 0;
raise ECommsError.Create( 'Unable to create event' )
end;

// Create the Read thread.
try
ReadThread := TReadThread.Create( True {suspended} );
except
ReadThread := nil;
CloseHandle( hCloseEvent );
CloseHandle( hCommFile );
hCommFile := 0;
raise ECommsError.Create( 'Unable to create read thread' )
end;
ReadThread.hCommFile := hCommFile;
ReadThread.hCloseEvent := hCloseEvent;
ReadThread.hComm32Window := FHWnd;

// Comm threads should have a higher base priority than the UI thread.
// If they don't, then any temporary priority boost the UI thread gains
// could cause the COMM threads to loose data.
ReadThread.Priority := tpHighest;

// Create the Write thread.
try
WriteThread := TWriteThread.Create( True {suspended} );
except
CloseReadThread;
WriteThread := nil;
CloseHandle( hCloseEvent );
CloseHandle( hCommFile );
hCommFile := 0;
raise ECommsError.Create( 'Unable to create write thread' )
end;
WriteThread.hCommFile := hCommFile;
WriteThread.hCloseEvent := hCloseEvent;
WriteThread.hComm32Window := FHWnd;
WriteThread.pFSendDataEmpty := @FSendDataEmpty;

WriteThread.Priority := tpHigher;

ReadThread.Resume;
WriteThread.Resume

// Everything was created ok. Ready to go!
end;

如果把comm1.CommName:='com10'就会出现“Error opening serial port”
附上spcomm这段打开串口的程序：
procedure TComm.StartComm;
var
hNewCommFile: THandle;
begin
// Are we already doing comm?
if (hCommFile <> 0) then
raise ECommsError.Create( 'This serial port already opened' );

hNewCommFile := CreateFile( PChar(FCommName),
GENERIC_READ or GENERIC_WRITE,
0, {not shared}
nil, {no security ??}
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL or FILE_FLAG_OVERLAPPED,
0 {template} );

if hNewCommFile = INVALID_HANDLE_VALUE then
raise ECommsError.Create( 'Error opening serial port' );//[red]就是这个地方[/red]

// Is this a valid comm handle?
if GetFileType( hNewCommFile ) <> FILE_TYPE_CHAR then
begin
CloseHandle( hNewCommFile );
raise ECommsError.Create( 'File handle is not a comm handle ' )
end;

if not SetupComm( hNewCommFile, 4096, 4096 ) then
begin
CloseHandle( hCommFile );
raise ECommsError.Create( 'Cannot setup comm buffer' )
end;

// It is ok to continue.

hCommFile := hNewCommFile;

// purge any information in the buffer

PurgeComm( hCommFile, PURGE_TXABORT or PURGE_RXABORT or
PURGE_TXCLEAR or PURGE_RXCLEAR ) ;
FSendDataEmpty := True;

// Setting the time-out value
_SetCommTimeout;

// Querying then setting the comm port configurations.
_SetCommState;

// Create the event that will signal the threads to close.
hCloseEvent := CreateEvent( nil, True, False, nil );

if hCloseEvent = 0 then
begin
CloseHandle( hCommFile );
hCommFile := 0;
raise ECommsError.Create( 'Unable to create event' )
end;

// Create the Read thread.
try
ReadThread := TReadThread.Create( True {suspended} );
except
ReadThread := nil;
CloseHandle( hCloseEvent );
CloseHandle( hCommFile );
hCommFile := 0;
raise ECommsError.Create( 'Unable to create read thread' )
end;
ReadThread.hCommFile := hCommFile;
ReadThread.hCloseEvent := hCloseEvent;
ReadThread.hComm32Window := FHWnd;

// Comm threads should have a higher base priority than the UI thread.
// If they don't, then any temporary priority boost the UI thread gains
// could cause the COMM threads to loose data.
ReadThread.Priority := tpHighest;

// Create the Write thread.
try
WriteThread := TWriteThread.Create( True {suspended} );
except
CloseReadThread;
WriteThread := nil;
CloseHandle( hCloseEvent );
CloseHandle( hCommFile );
hCommFile := 0;
raise ECommsError.Create( 'Unable to create write thread' )
end;
WriteThread.hCommFile := hCommFile;
WriteThread.hCloseEvent := hCloseEvent;
WriteThread.hComm32Window := FHWnd;
WriteThread.pFSendDataEmpty := @FSendDataEmpty;

WriteThread.Priority := tpHigher;

ReadThread.Resume;
WriteThread.Resume

// Everything was created ok. Ready to go!
end;

hNewCommFile := CreateFile(PChar('//./'+FCommName), // '//./'+ add by DfHuang.就是这里的问题。
GENERIC_READ or GENERIC_WRITE,
0, {not shared}
nil, {no security ??}
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL or FILE_FLAG_OVERLAPPED,
0 {template} );

同意hdfsun的意见