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POHow do I marshal a pointer to a series of null-terminated strings in C#?
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  1. POHow do I marshal a pointer to a series of null-terminated strings in C#?
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    copied!<p>I need some help with the following. I've got a c++ API (no access to source) and I'm struggling with the methods returning char* attributes, or returned structures containing char* attributes. According to the API's documentation the return value is as follows: </p> <p>Return Values<br> If the function succeeds, the return value is a pointer to a series of null-terminated strings, one for each project on the host system, ending with a second null character. The following example shows the buffer contents with <code>&lt;null&gt;</code> representing the terminating null character:</p> <pre><code>project1&lt;null&gt;project2&lt;null&gt;project3&lt;null&gt;&lt;null&gt; </code></pre> <p>If the function fails, the return value is NULL</p> <p>The problem I'm having is that the returned pointer in C# only contains the first value... project1 in this case. How can I get the full list to be able to loop through them on the managed side?</p> <p>Here's the c# code:</p> <blockquote> <pre><code> [DllImport("vmdsapi.dll", EntryPoint = "DSGetProjectList", CallingConvention = CallingConvention.Cdecl)] public static extern IntPtr DSGetProjectList(); </code></pre> </blockquote> <p>Calling method:</p> <blockquote> <pre><code> IntPtr ptrProjectList = DSAPI.DSGetProjectList(); string strProjectList = Marshal.PtrToStringAnsi(ptrProjectList).ToString(); </code></pre> </blockquote> <p>strProjectList only contains the first item.<br> Here's the info from the API's header file...</p> <blockquote> <pre><code> DllImport char *DSGetProjectList dsproto((void)); </code></pre> </blockquote> <p>Here's some sample code from a c++ console app which I've used for testing purposes...</p> <blockquote> <pre><code> char *a; a = DSGetProjectList( ); while( *a ) { printf("a=%s\n", a); a += 1 + strlen(a); } </code></pre> </blockquote> <p>Each iteration correctly displays every project in the list.</p>
 

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