IntPtr overloads for System.Array arguments about hdf.pinvoke HOT 6 CLOSED

Like this: ?

public extern static ssize_t get_name(hid_t attr_id, size_t size, IntPtr name);

   [TestMethod]
   public unsafe void H5Aget_nameTest5()
   {
       size_t buf_size = IntPtr.Zero;
       ssize_t size = IntPtr.Zero;
       hid_t att = H5A.create(m_v2_test_file, "H5Aget_name", H5T.IEEE_F64LE, m_space_scalar);
       Assert.IsTrue(att >= 0);

       // pretend we don't know the size
       size = H5A.get_name(att, buf_size, IntPtr.Zero);
       Assert.IsTrue(size.ToInt32() == 11);
       buf_size = new IntPtr(size.ToInt32() + 1);

       char* namePtr = stackalloc char[(int)buf_size];
       size = H5A.get_name(att, buf_size, (IntPtr)namePtr);
       Assert.IsTrue(size.ToInt32() == 11);
       string name = Marshal.PtrToStringAnsi((IntPtr)namePtr);
       // names should match
       Assert.AreEqual("H5Aget_name", name);
   }

I'm not working with unsafe code so I never came around stackalloc until now. Do you use it for performance reasons ?

from hdf.pinvoke.

Exactly. In this particular example we probably could get away with StringBuilder or [MarshalAs] on a plain string (have not tried though). stackallow becomes even more useful if you just need a temporary int[] array for defining dimension lengths or hyperslab parameters a.t.l.
stackalloc also often allows to write code which is free of new statements, which can be of advantage in multithreaded setups to prevent from contention by global locks.

We are currently integrating HDF.PInvoke into ILNumerics.IO.HDF and will add pointer overloads at all places we find useful. However, we do not cover all features of HDF5 yet.

from hdf.pinvoke.

Basically, those pointer overloads must simply reflect the HDF5 C API in a 1:1 manner.

from hdf.pinvoke.

I'd be fine with that. Let's discuss this at the next pow wow!

from hdf.pinvoke.

See issue #72 as a first step. More to come as needed/requested.

from hdf.pinvoke.

tested and working fine. (nuget 1.8.17.2, 1.10)

from hdf.pinvoke.