Hi Liu,

Unfortunately almost everything is wrong in your code, which is probably translated from VB. The translation is incomplete.

(1) External function parameters in Visual FoxPro must be declared as
INTEGER lpNumberOfBytes
not as
lpNumberOfBytes As Integer

(2) GENERIC_READ or GENERIC_WRITE does not work in Visual FoxPro the way it works in Visual Basic.
You should change it to BitOr(GENERIC_READ, GENERIC_WRITE).
Actually even (GENERIC_READ + GENERIC_WRITE) works Ok in this case.

So finally your code should be this way:

#DEFINE GENERIC_READ         0x80000000
#DEFINE GENERIC_WRITE        0x40000000
#DEFINE OPEN_EXISTING        3
#DEFINE FILE_FLAG_OVERLAPPED 0x40000000

DECLARE INTEGER CreateFile IN kernel32;
	STRING lpFileName, INTEGER dwDesiredAccess, INTEGER dwShareMode,;
	INTEGER lpSecurityAttributes, INTEGER dwCreationDisposition,;
	INTEGER dwFlagsAndAttributes, INTEGER hTemplateFile

DECLARE INTEGER CloseHandle IN kernel32 INTEGER hObject

* this already works
ICDEV = CreateFile('COM1', GENERIC_READ+GENERIC_WRITE, 0,0,;
	OPEN_EXISTING, FILE_FLAG_OVERLAPPED, 0)
? ICDEV
= CloseHandle(ICDEV)