CODEWITHSUNDEEP
c#pinvoke
user193437
user193437

Reputation:

Help with PInvoke

I got the next c function:

long _stdcall _MakePipeString(char *szOut, long nOutChars, const char *szXmlFile, long nOptions);

And I try to use pInvioke like this:

[DllImport("diXo10.dll")]
public static extern long _MakePipeString(out StringBuilder szOut, out long nOutChars, string szXmlFile, long nOptions);

But i get null in the ouput variable szOut.

Am I doing wrong?

Please help.

Upvotes: 0

Views: 238

Answers (3)

Mattias S
Mattias S

Reputation: 4798

In additions to what others have said, change the longs to ints on the C# side.

Upvotes: 1

manji
manji

Reputation: 47968

try without the out parameter.

see here.

Upvotes: 0

Lucero
Lucero

Reputation: 60190

Have you tried:

[DllImport("diXo10.dll")]
public static extern long _MakePipeString([MarshalAs(UnmanagedType.LPStr)] out String szOut, out long nOutChars, [MarshalAs(UnmanagedType.LPStr)] string szXmlFile, long nOptions);

Note that you may also have to specify whether you expect ANSI or Unicode(UTF16) characters, for instance by using LPTStr/LPWStr instead of LPStr or on the DllImport attribute.

Upvotes: 0

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