Re: p/invoke _stat - C# Discussion Boards

19-Jan-11 5:16

Hi,

does anyone know how to call _stat with p/invoke from C#?

it is posible to use File.Get* instead, but I need the direct call to
investigate something on the file system.

Thanks

Richard MacCutchan19-Jan-11 5:53

19-Jan-11 5:53

Although this link[^] is not for _stat() it should help you figure it out.

I must get a clever new signature for 2011.

DanielWehrle19-Jan-11 20:37

19-Jan-11 20:37

No sorry it is only fclose on the linkt, I check pinvoke.net before my post and did not find anything.

Richard MacCutchan19-Jan-11 21:32

19-Jan-11 21:32

DanielWehrle wrote:
it is only fclose on the link

Yes, I know that, but if you look at the sample you should be able to figure out how to code the call for the _stat() function.

I must get a clever new signature for 2011.

DanielWehrle19-Jan-11 21:44

19-Jan-11 21:44

The pure _stat call is not my reral problem, but I have no idear how to define the struct containing the _stat result

DanielWehrle20-Jan-11 0:05

20-Jan-11 0:05

I try to do itz like:

[StructLayout(LayoutKind.Sequential)]
public struct STAT
{
public uint st_dev;
public ushort st_ino;
public ushort st_mode;
public short st_nlink;
public short st_uid;
public short st_gid;
public uint st_rdev;
public long st_size;
public long st_atime;
public long st_mtime;
public long st_ctime;
}

[DllImport("msvcrt.dll", SetLastError = true)]
static extern int _stat(string file, ref STAT buf);

But recive an PInvoke Imbalance Exception.

Tony Richards20-Jan-11 0:42

Tony Richards

20-Jan-11 0:42

Have you checked the calling convention? The last time I got an error like this, this was the reason.

Oh, and please use <pre></pre> to make your code clearer

DanielWehrle20-Jan-11 1:35

20-Jan-11 1:35

Yes but I'm not sure what the calling conventions for the _stat call are.

All I know is from: http://msdn.microsoft.com/en-us/library/14h5k7ff%28vs.71%29.aspx

Richard MacCutchan20-Jan-11 1:27

20-Jan-11 1:27

DanielWehrle wrote:
But recive an PInvoke Imbalance Exception.

If you have an exception, it really is better if you post the exact text that you receive, rather than your interpretation of it. Also the line(s) of code that caused the exception; always included within <pre></pre> tags for readability.

I must get a clever new signature for 2011.

DanielWehrle20-Jan-11 1:47

20-Jan-11 1:47

PInvokeStackImbalance
Message: A call to PInvoke function 'SharpFastStatWrite!SharpFastStatWrite.Writer::_stat' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.

Thanks

Richard MacCutchan20-Jan-11 3:50

20-Jan-11 3:50

Well this took me some time to figure out but I finally noticed that the function prototype for _stat is

int __cdecl _stat(_In_z_ const char * _Name, _Out_ struct _stat32 * _Stat);

and that __cdecl is not the standard calling convention. So I changed the DLLImport as follows

[DllImport("msvcrt.dll", SetLastError = true, CallingConvention=CallingConvention.Cdecl)]

and it now works.

Give it a try.

I must get a clever new signature for 2011.

Richard MacCutchan20-Jan-11 7:14

20-Jan-11 7:14

Further information, the STAT structure should be as follows:

public struct STAT
{
    public uint st_dev;
    public ushort st_ino;
    public ushort st_mode;
    public short st_nlink;
    public short st_uid;
    public short st_gid;
    public uint st_rdev;
    public uint st_size;
    public uint st_atime;
    public uint st_mtime;
    public uint st_ctime;
}

Note the last four entries are uint rather than long values.

I must get a clever new signature for 2011.

DanielWehrle20-Jan-11 20:29

20-Jan-11 20:29

Thanks, now it work.

Richard MacCutchan20-Jan-11 21:31

Programming Scanner Hardware

20-Jan-11 21:31

You're welcome; perhaps you would be so kind as to vote my answer (the one with the solution)?

I must get a clever new signature for 2011.

RobScripta19-Jan-11 4:43

RobScripta

19-Jan-11 4:43

I have an application in C# to process scanned invoices. A customer wants to buy a scanner for the application but has these simple requirements:
- Some 50 invoices are received each day, 40 of them single page, 10 multi page
- The 40 single page invoices are put in a stack on the ADF and the "single" button on the scanner is pushed. The scanner then creates 40 files from the 40 invoices, ready for further processing.
- The first multi page invoice is put on the adf and the "multi" button on the scanner is pushed. The scanner then creates 1 (PDF) file from all pages in the adf
- the second multi page invoice etc...

What I want is to program the buttons on the scanner to do exactly that (with resolution and color depth etc). It may be on a network scanner, it may also be an USB scanner (with software running on a dedicated PC).
It must exist, I think it's a reasonable request, but extensive googling gives millions of results but nothing usefull.

Can anybody give me a pointer ?

Rob

Richard MacCutchan19-Jan-11 5:15

19-Jan-11 5:15

PosiRob wrote:
but extensive googling gives millions of results but nothing usefull.

A single Google search revealed this article[^], which should get you started.

I must get a clever new signature for 2011.

RobScripta19-Jan-11 5:27

RobScripta

19-Jan-11 5:27

I'm sorry but scanning from my applications is allmost daily work. I need to scan from the hardware for this solution.

Thanks for your effort.

Rob

Richard MacCutchan19-Jan-11 5:44

19-Jan-11 5:44

PosiRob wrote:
I need to scan from the hardware for this solution.

Well, you forgot to mention that in your initial question. Maybe you should check with the manufacturers to see if there is a published API for their device.

I must get a clever new signature for 2011.

RobScripta20-Jan-11 1:06

RobScripta

20-Jan-11 1:06

Thank you for trying to be helpfull, just for the record: in my initial post I mentioned:
"and the "single" button on the scanner is pushed"

I can easily create the thing from software, but I want to do it from the hardware. There has been no purchase of a scanner yet, I first want to establish the possibility before I advise to buy something..

Rob

Richard MacCutchan20-Jan-11 1:39