How big is a C BOOLEAN

[Dale]

Stupid question, but since I can't find it in the VS help...
I need to create a structure and pass it to a Win32 API function.

How many bytes is a C BOOLEAN? And is it the same size as a C#
bool/System.Boolean? If so is it set (values) the same, or do I need to
create an integer of the required size and set it to 0 or -1 as required for
passing to the external Win32 DLL?

Thanks.

Dale

[Bradley1234]

There is a method you can call in .net to show the size, but I dont have it
handy, you would instantiate some variable then print and call something to
show the size;

Isnt a C boolean the same size as INT?

And I think its either zero for false or non-zero (undefined) for true?
"Dale" <da******@foxcustomsoftware.com> wrote in message
news:aV7td.448262$nl.23846@pd7tw3no...

Stupid question, but since I can't find it in the VS help...
I need to create a structure and pass it to a Win32 API function.

How many bytes is a C BOOLEAN? And is it the same size as a C#
bool/System.Boolean? If so is it set (values) the same, or do I need to
create an integer of the required size and set it to 0 or -1 as required for passing to the external Win32 DLL?

Thanks.

Dale

[Mihai N.]

>> How many bytes is a C BOOLEAN? And is it the same size as a C#

bool/System.Boolean? If so is it set (values) the same, or do I need to
create an integer of the required size and set it to 0 or -1 as required

for

passing to the external Win32 DLL?

I don't think C has a BOOLEAN type. Most likely a #define.
But if you have it defined somewhere and you want the size,
try printing sizeof(BOOLEAN).
You can also print TRUE and FALSE (also #defines, if you ask me)
--
Mihai
-------------------------
Replace _year_ with _ to get the real email

[Mattias Sjögren]

Stupid question, but since I can't find it in the VS help...
Not exactly what you're asking for, but see
http://msdn.microsoft.com/library/en...orbooleans.asp

How many bytes is a C BOOLEAN?
The Win32 BOOELAN type is 1 byte. It's defined as

typedef BYTE BOOLEAN;

in Winnt.h in the Platform SDK.

And is it the same size as a C# bool/System.Boolean?
Yes

If so is it set (values) the same, or do I need to
create an integer of the required size and set it to 0 or -1 as required for
passing to the external Win32 DLL?

No, the runtime can handle marshaling a managed bool to various kinds
of native ones, including BOOLEAN. Just apply the
MarshalAs(UnmanagedType.U1) attribute like the MSDN page linked to
above says.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Willy Denoyette [MVP]]

Beware the booleans!
Win32 defines different versions of booleans.
1. BOOL used by most Win32 API's, is an unsigned int (4 bytes)
2. BOOLEAN is a single byte, only used by a few win32 API's!!
3. and C/C++ has it's builtin 'bool' which is a single byte

Willy.

"Dale" <da******@foxcustomsoftware.com> wrote in message
news:aV7td.448262$nl.23846@pd7tw3no...

Stupid question, but since I can't find it in the VS help...
I need to create a structure and pass it to a Win32 API function.

How many bytes is a C BOOLEAN? And is it the same size as a C#
bool/System.Boolean? If so is it set (values) the same, or do I need to
create an integer of the required size and set it to 0 or -1 as required
for
passing to the external Win32 DLL?

Thanks.

Dale