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C# wrapper error code 6202

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C# wrapper error code 6202

I am writing a wrapper in C# to read TDM files.

OpenEx works fine.

 

[DllImport(lib, CharSet = CharSet.Auto)] static extern int DDC_OpenFileEx( [MarshalAs(UnmanagedType.LPStr)] string filePath, [MarshalAs(UnmanagedType.LPStr)] string fileType, int read_only, ref long file);

 but

 

[DllImport(lib, CharSet = CharSet.Auto)] static extern int DDC_GetFileStringPropertyLength(long file,

[MarshalAs(UnmanagedType.LPStr)]

string property, ref int length);

 

 

int len = 0;

errCode = ReadTDM.DDC_GetFileStringPropertyLength(fileh, "name", ref len);// fileh is passed form OpenEx fun

System.Console.WriteLine("length {0}", len);
System.Console.WriteLine("Error Code {0}", errCode);

 

 gives me an error  An invalid argument was passed to the library. I had tried ref uint length , didn't help.

 

 

 

 

 

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Re: C# wrapper error code 6202

We looked at the source code for DDC_GetFileStringPropertyLength and the only things that would cause it to

return DDC_InvalidArgument (-6202) is:

  • if the property name char* input parameter (2nd parameter) is NULL or empty string
  • if the length unsigned int* output parameter is NULL.

 

I'm not familiar enough with C# to tell whether there are any problems in the declarations of the DLL functions

or in how they are being called but maybe that helps you to solve the issue.

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Re: C# wrapper error code 6202

Thx for the reply.

I found out that I have two headers files nilibddc_m.h and nilibddc.h

 

in first one DDCFileHandle is a long type in the second on is a structure 

 

typedef struct _DDCFile DDCFile; typedef struct _DDCChannelGroup DDCChannelGroup; typedef struct _DDCChannel DDCChannel; typedef DDCFile* DDCFileHandle; typedef DDCChannelGroup* DDCChannelGroupHandle; typedef DDCChannel* DDCChannelHandle;

 

 but according to your post it should not be the cause of this error, should be?

 

 

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Re: C# wrapper error code 6202

some additional info:

Windows 7 32bit and lib form the 32-bit subfoler

example SinData.tdm form http://digital.ni.com/public.nsf/allkb/A3663DE39D6A2C5A86257204005C11CA?OpenDocument

 

and the String is not the problem

 

 

/// <summary> /// GetNumChannelGroups /// </summary> [DllImport(lib)] static extern int DDC_GetNumChannelGroups(long file, ref uint numChannelGroups);

 

 

 

 

uint numGru = 0; errCode = ReadTDM.DDC_GetNumChannelGroups(fileh, ref numGru); System.Console.WriteLine("Error Code {0} GetNumChannelGroups", errCode);

 

 also returs the -6202 code, hence is numGru.

 

 

 

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Re: C# wrapper error code 6202

Solved Smiley Happy

 

file must be int not long

 

http://digital.ni.com/public.nsf/allkb/A3663DE39D6A2C5A86257204005C11CA?OpenDocument 

 

 nilibddc.h says

 

 typedef long            DDCFileHandle;
typedef long            DDCChannelGroupHandle;
typedef long            DDCChannelHandle;

 

 

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