C typedef to PB Type question

[Wayne Hill]

How do I handle the " DWORD fReserved : 25; " statement in PB?

'C++
typedef struct _FTCOMSTAT { 
	DWORD fCtsHold : 1; 
	DWORD fDsrHold : 1; 
	DWORD fRlsdHold : 1; 
	DWORD fXoffHold : 1; 
	DWORD fXoffSent : 1; 
	DWORD fEof : 1; 
	DWORD fTxim : 1; 
	DWORD fReserved : 25; 
	DWORD cbInQue; 
	DWORD cbOutQue;
} FTCOMSTAT, *LPFTCOMSTAT;


' PB  
TYPE FTCOMSTAT
	 fCtsHold AS DWORD ': 1;
	 fDsrHold AS DWORD ': 1;
	 fRlsdHold AS DWORD ': 1;
	 fXoffHold AS DWORD ': 1;
	 fXoffSent AS DWORD ': 1;
	 fEof AS DWORD ': 1;
	 fTxim AS DWORD ': 1;
	 fReserved AS DWORD ': 25; ???
	 cbInQue AS DWORD ';
	 cbOutQue AS DWORD ';}
END TYPE

------------------
Wayne

wayne_j_hill(at)yahoo.com

[Michael Puckett]

I don't think this is possible Wayne.

Forgive me if you know this, but a C/C++ statement like

DWORD fCtsHold : 1;

Says "Map or reserve 1 bit (from A DWORD) for this value"

DWORD fReserved : 25;

Says "Map or reserve aside 25 bits (from A DWORD) for this value"

You'll notice that variables fCtsHold ... fReserved inclusive add up to 32 bits, the room in a DWORD ...

So your TYPE declaration wouldn't work, i.e.

fCtsHold AS DWORD

Is 32 bits, not 1 etc. so your entire TYPE DEF is *far* wider than the C Struct your trying to mimic.

I don't think PowerBASIC allows alottment down to the bit level, though I could be wrong. I think the best you could hope for is to make sure your TYPE DEF is the same width / data type and then pull out the individual bit values after dumping data to it by bit twiddling as required.

Just sharing my ignorance really,

Cheers,

Michael.

[Tom Hanlin]

Like Michael says.

See TYPE COMSTAT in your Win32API.inc file-- it's already defined.

The ":#" thing is the C way of specifying bitfields. In PowerBASIC,
you'll need to use something like the BIT function and statement,
or AND/OR bitmasks, instead.

------------------
Tom Hanlin
PowerBASIC Staff