How are variable length strings stored

Hdf-forum archives
1

Hello Everyone,

If I have a compound type's made up of primitives

  STD_I32LE
  IEEE_F64LE
  ...

then Hdf5 will store this as a plain old data type with everything
next to each other in a fixed, predictable way. I have also found
this to be true for fixed length strings. How does Hdf5 handle
variable length strings? Does it put it inline, or is there a heap
somewhere else? Is there any documentation about what the heap looks
like?

Thanks,
Walter Landry

2

Walt, variable length data is stored in the global heap. See sections
IV.B. Disk Format: Level 2B - Data Object Data Storage
and III.E. Disk Format: Level 1E - Global Heap
of the file format spec. (https://www.hdfgroup.org/HDF5/doc/H5.format.html\)

Best, G.

···

-----Original Message-----
From: Hdf-forum [mailto:hdf-forum-bounces@lists.hdfgroup.org] On Behalf Of Walter Landry
Sent: Monday, March 7, 2016 3:02 AM
To: hdf-forum@lists.hdfgroup.org
Subject: [Hdf-forum] How are variable length strings stored

Hello Everyone,

If I have a compound type's made up of primitives

  STD_I32LE
  IEEE_F64LE
  ...

then Hdf5 will store this as a plain old data type with everything next to each other in a fixed, predictable way. I have also found this to be true for fixed length strings. How does Hdf5 handle variable length strings? Does it put it inline, or is there a heap somewhere else? Is there any documentation about what the heap looks like?

Thanks,
Walter Landry

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3

Thanks. That is exactly what I needed.

Cheers,
Walter Landry

···

Gerd Heber <gheber@hdfgroup.org> wrote:

Walt, variable length data is stored in the global heap. See sections
IV.B. Disk Format: Level 2B - Data Object Data Storage
and III.E. Disk Format: Level 1E - Global Heap
of the file format spec. (https://www.hdfgroup.org/HDF5/doc/H5.format.html)