Many thanks, that worked a treat. I have attached my working method below.
Matt
/// <summary>
/// Helper method that extracts a string array value from a variable
length attribute.
/// See
https://github.com/HDFGroup/HDF.PInvoke/blob/master/UnitTests/H5DTest/H5Dread.cs
/// </summary>
/// <param name="aid">The id of the attribute.</param>
/// <param name="tid">The type id of the attribute.</param>
/// <returns>An array of strings.</returns>
public string[] GetStrings(long aid, long tid)
{
long space = H5A.get_space(aid);
// TODO close space
long count = H5S.get_simple_extent_npoints(space);
// Create pointer [] to receive the addresses.
IntPtr[] rdata = new IntPtr[count];
// Create array for result.
string[] result = new string[count];
GCHandle hnd = GCHandle.Alloc(rdata, GCHandleType.Pinned);
// Call the function with address of pointer [].
H5A.read(aid, tid, hnd.AddrOfPinnedObject());
hnd.Free();
// For each pointer extract string.
for (int ii = 0; ii < rdata.Length; ++ii)
{
int len = 0;
// Find the end of the string (\0)
while (Marshal.ReadByte(rdata[ii], len) != 0) { ++len; }
byte[] buffer = new byte[len];
// Copy to buffer
Marshal.Copy(rdata[ii], buffer, 0, buffer.Length);
// Encode the string.
result[ii] = Encoding.UTF8.GetString(buffer);
}
return result;
}
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