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hdf5/docs/doxygen/dox/FileFormatDisc.dox
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Scot Breitenfeld 05676d1abe Consolidate documentation under docs/ directory (#6310) 
* Consolidate documentation under doc/ directory

Move user-facing guides from release_docs/ and doxygen/ into a single
doc/ root. release_docs/ now holds only release artifacts (changelogs,
history, release process, maintainer info).

- git mv release_docs/INSTALL*.md, USING_*.md, README_HPC.md,
  BuildSystemNotes.md, AutotoolsToCMakeOptions.md,
  HDF5_Library_2.0.0_Migration_Guide.md → doc/
- git mv doxygen/ → doc/doxygen/
- Update CMakeLists.txt: HDF5_DOXYGEN_DIR and add_subdirectory path
- Update CMakeInstallation.cmake: all install paths for moved files
- Update bin/make_vers: hardcoded doxygen/ path substitution
- Update doc/doxygen/CMakeLists.txt: EXAMPLES_DIRECTORY and comments
- Update README.md, CONTRIBUTING.md, SECURITY.md, config/README.md,
  release_docs/RELEASE_PROCESS.md: links to moved files
- Update doxygen .dox files: release_docs/ URLs for moved guides
- Rewrite release_docs/README.md for narrowed scope

* Add HDF5_DOCS_DIR variable for doc/ root path

Introduce HDF5_DOCS_DIR = \${HDF5_SOURCE_DIR}/doc so that
CMakeInstallation.cmake and future callers reference the doc/
directory symbolically rather than by hardcoded path.
HDF5_DOXYGEN_DIR is now derived from HDF5_DOCS_DIR.
2026-03-31 17:01:54 -06:00

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/** \page FMTDISC HDF5 File Format Discussion
Navigate back: \ref index "Main" / \ref TN
<hr>
<dl>
<dt>Document's Audience:</dt>
<dd>Current H5 library designers and knowledgeable external developers.</dd>
<dt>Background Reading:</dt>
<dd>\ref FMT4 <br />This describes the current HDF5 file format.</dd>
</dl>
\section sec_fmtdisc_intro Introduction
<strong>What is this document about?</strong><br />
This document attempts to explain the HDF5 file format specification with a
few examples and describes some potential improvements to the format specification.
\section sec_fmtdisc_exam File Format Examples
This section has several small programs and describes the format of a file
created with each of them.
Example program one - <em>Create an empty file</em>:
\code
#include "hdf5.h"
#include <assert.h>
int main()
{
hid_t fid; /* File ID */
herr_t ret; /* Generic return value */
/* Create the file */
fid=H5Fcreate("example1.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
assert(fid&gt;=0);
/* Close the file */
ret=H5Fclose(fid);
assert(ret&gt;=0);
return(0);
}
\endcode
<table>
<caption><strong>Super Block</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td>\211</td>
<td>'H'</td>
<td>'D'</td>
<td>'F'</td>
</tr>
<tr align="center">
<td>\\r</td>
<td>\\n</td>
<td>\032</td>
<td>\\n</td>
</tr>
<tr align="center">
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr align="center">
<td>0</td>
<td>8</td>
<td>8</td>
<td>0</td>
</tr>
<tr align="center">
<td colspan="2">4</td>
<td colspan="2">16</td>
</tr>
<tr align="center">
<td colspan="4">0x00000003</td>
</tr>
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4"><br />0xffffffffffffffff<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4">?</td>
</tr>
<tr align="center">
<td colspan="4"><br />0xffffffffffffffff<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4"><br />928<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4">H5G_CACHED_STAB (1)</td>
</tr>
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<tr align="center">
<td colspan="4"><br />384<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4"><br />96<br /><br /></td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
</table>
\code
%h5debug example1.h5
Reading signature at address 0 (rel)
File Super Block...
File name: example1.h5
File access flags 0x00000000
File open reference count: 1
Address of super block: 0 (abs)
Size of user block: 0 bytes
Super block version number: 0
Free list version number: 0
Root group symbol table entry version number: 0
Shared header version number: 0
Size of file offsets (haddr_t type): 8 bytes
Size of file lengths (hsize_t type): 8 bytes
Symbol table leaf node 1/2 rank: 4
Symbol table internal node 1/2 rank: 16
File consistency flags: 0x00000003
Base address: 0 (abs)
Free list address: UNDEF (rel)
Address of driver information block: UNDEF (rel)
Root group symbol table entry:
Name offset into private heap: 0
Object header address: 928
Dirty: Yes
Cache info type: Symbol Table
Cached information:
B-tree address: 384
Heap address: 96
\endcode
<table>
<caption><strong>Root Group Object Header</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td width="25%">1</td>
<td width="25%">0</td>
<td colspan="2" width="50%">2</td>
</tr>
<tr align="center">
<td colspan="4">1</td>
</tr>
<tr align="center">
<td colspan="4">32</td>
</tr>
<tr align="center">
<td colspan="2">0x0011</td>
<td colspan="2">16</td>
</tr>
<tr align="center">
<td>0x01</td>
<td colspan="3">0</td>
</tr>
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<tr align="center">
<td colspan="4"><br />384<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4"><br />96<br /><br /></td>
</tr>
</table>
</td>
</tr>
<tr align="center">
<td colspan="2">0</td>
<td colspan="2">0</td>
</tr>
<tr align="center">
<td>0x00</td>
<td colspan="3">0</td>
</tr>
</table>
\code
%h5debug example1.h5 928
New address: 928
Reading signature at address 928 (rel)
Object Header...
Dirty: 0
Version: 1
Header size (in bytes): 16
Number of links: 1
Number of messages (allocated): 2 (32)
Number of chunks (allocated): 1 (8)
Chunk 0...
Dirty: 0
Address: 944
Size in bytes: 32
Message 0...
Message ID (sequence number): 0x0011 stab(0)
Shared message: No
Constant: Yes
Raw size in obj header: 16 bytes
Chunk number: 0
Message Information:
B-tree address: 384
Name heap address: 96
Message 1...
Message ID (sequence number): 0x0000 null(0)
Shared message: No
Constant: No
Raw size in obj header: 0 bytes
Chunk number: 0
Message Information:
<no info="" for="" this="" message="">
\endcode
<table>
<caption><strong>Root Group Local Heap</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td>'H'</td>
<td>'E'</td>
<td>'A'</td>
<td>'P'</td>
</tr>
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4">256</td>
</tr>
<tr align="center">
<td colspan="4">8</td>
</tr>
<tr align="center">
<td colspan="4">128</td>
</tr>
</table>
\code
%h5debug example1.h5 96
New address: 96
Reading signature at address 96 (rel)
Local Heap...
Dirty: 0
Header size (in bytes): 32
Address of heap data: 128
Data bytes allocated on disk: 256
Data bytes allocated in core: 256
Free Blocks (offset, size):
Block #0: 8, 248
Percent of heap used: 3.12%
Data follows (`__' indicates free region)...
0: 00 00 00 00 00 00 00 00 __ __ __ __ __ __ __ __ ........
16: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
32: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
48: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
64: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
80: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
96: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
112: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
128: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
144: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
160: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
176: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
192: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
208: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
224: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
240: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
\endcode
<table>
<caption><strong>Root Group B-tree</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td>'T'</td>
<td>'R'</td>
<td>'E'</td>
<td>'E'</td>
</tr>
<tr align="center">
<td>0</td>
<td>0</td>
<td colspan="2">0</td>
</tr>
<tr align="center">
<td colspan="4"><br />0xffffffffffffffff<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4"><br />0xffffffffffffffff<br /><br /></td>
</tr>
</table>
\code
%h5debug example1.h5 384 96
New address: 384
Reading signature at address 384 (rel)
Tree type ID: H5B_SNODE_ID
Size of node: 544
Size of raw (disk) key: 8
Dirty flag: False
Number of initial dirty children: 0
Level: 0
Address of left sibling: UNDEF
Address of right sibling: UNDEF
Number of children (max): 0 (32)
\endcode
Example program two - <em>Create a file with a single dataset in it</em>:
\code
#include "hdf5.h"
#include <assert.h>
int main()
{
hid_t fid; /* File ID */
hid_t sid; /* Dataspace ID */
hid_t did; /* Dataset ID */
herr_t ret; /* Generic return value */
/* Create the file */
fid=H5Fcreate("example2.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
assert(fid&gt;=0);
/* Create a scalar dataspace for the dataset */
sid=H5Screate(H5S_SCALAR);
assert(sid&gt;=0);
/* Create a trivial dataset */
did=H5Dcreate(fid, "Dataset", H5T_NATIVE_INT, sid, H5P_DEFAULT);
assert(did&gt;=0);
/* Close the dataset */
ret=H5Dclose(did);
assert(ret&gt;=0);
/* Close the dataspace */
ret=H5Sclose(sid);
assert(ret&gt;=0);
/* Close the file */
ret=H5Fclose(fid);
assert(ret&gt;=0);
return(0);
}
\endcode
<table border="">
<caption align="top"><strong>Super Block</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td>\211</td>
<td>'H'</td>
<td>'D'</td>
<td>'F'</td>
</tr>
<tr align="center">
<td>\\r</td>
<td>\\n</td>
<td>\032</td>
<td>\\n</td>
</tr>
<tr align="center">
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr align="center">
<td>0</td>
<td>8</td>
<td>8</td>
<td>0</td>
</tr>
<tr align="center">
<td colspan="2">4</td>
<td colspan="2">16</td>
</tr>
<tr align="center">
<td colspan="4">0x00000003</td>
</tr>
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4"><br />0xffffffffffffffff<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4">?</td>
</tr>
<tr align="center">
<td colspan="4"><br />0xffffffffffffffff<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4"><br />928<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4">H5G_CACHED_STAB (1)</td>
</tr>
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<tr align="center">
<td colspan="4"><br />384<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4"><br />96<br /><br /></td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
</table>
\code
%h5debug example2.h5
Reading signature at address 0 (rel)
File Super Block...
File name: example2.h5
File access flags 0x00000000
File open reference count: 1
Address of super block: 0 (abs)
Size of user block: 0 bytes
Super block version number: 0
Free list version number: 0
Root group symbol table entry version number: 0
Shared header version number: 0
Size of file offsets (haddr_t type): 8 bytes
Size of file lengths (hsize_t type): 8 bytes
Symbol table leaf node 1/2 rank: 4
Symbol table internal node 1/2 rank: 16
File consistency flags: 0x00000003
Base address: 0 (abs)
Free list address: UNDEF (rel)
Address of driver information block: UNDEF (rel)
Root group symbol table entry:
Name offset into private heap: 0
Object header address: 928
Dirty: Yes
Cache info type: Symbol Table
Cached entry information:
B-tree address: 384
Heap address: 96
\endcode
<table border="">
<caption align="top"><strong>Root Group Object Header</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td width="25%">1</td>
<td width="25%">0</td>
<td colspan="2" width="50%">2</td>
</tr>
<tr align="center">
<td colspan="4">1</td>
</tr>
<tr align="center">
<td colspan="4">32</td>
</tr>
<tr align="center">
<td colspan="2">0x0011</td>
<td colspan="2">16</td>
</tr>
<tr align="center">
<td>0x01</td>
<td colspan="3">0</td>
</tr>
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<tr align="center">
<td colspan="4"><br />384<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4"><br />96<br /><br /></td>
</tr>
</table>
</td>
</tr>
<tr align="center">
<td colspan="2">0</td>
<td colspan="2">0</td>
</tr>
<tr align="center">
<td>0x00</td>
<td colspan="3">0</td>
</tr>
</table>
\code
%h5debug example2.h5 928
New address: 928
Reading signature at address 928 (rel)
Object Header...
Dirty: 0
Version: 1
Header size (in bytes): 16
Number of links: 1
Number of messages (allocated): 2 (32)
Number of chunks (allocated): 1 (8)
Chunk 0...
Dirty: 0
Address: 944
Size in bytes: 32
Message 0...
Message ID: 0x0011 stab(0)
Shared message: No
Constant: Yes
Raw size in obj header: 16 bytes
Chunk number: 0
Message Information:
B-tree address: 384
Name heap address: 96
Message 1...
Message ID: 0x0000 null(0)
Shared message: No
Constant: No
Raw size in obj header: 0 bytes
Chunk number: 0
Message Information:
<no info="" for="" this="" message="">
\endcode
<table border="">
<caption align="top"><strong>Root Group Local Heap</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td>'H'</td>
<td>'E'</td>
<td>'A'</td>
<td>'P'</td>
</tr>
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4">256</td>
</tr>
<tr align="center">
<td colspan="4">16</td>
</tr>
<tr align="center">
<td colspan="4">128</td>
</tr>
</table>
\code
%h5debug example2.h5 96
New address: 96
Reading signature at address 96 (rel)
Local Heap...
Dirty: 0
Header size (in bytes): 32
Address of heap data: 128
Data bytes allocated on disk: 256
Data bytes allocated in core: 256
Free Blocks (offset, size):
Block #0: 16, 240
Percent of heap used: 6.25%
Data follows (`__' indicates free region)...
0: 00 00 00 00 00 00 00 00 44 61 74 61 73 65 74 00 ........Dataset.
16: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
32: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
48: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
64: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
80: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
96: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
112: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
128: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
144: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
160: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
176: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
192: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
208: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
224: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
240: __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
\endcode
<table border="">
<caption align="top"><strong>Root Group B-tree</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td>'T'</td>
<td>'R'</td>
<td>'E'</td>
<td>'E'</td>
</tr>
<tr align="center">
<td>0</td>
<td>0</td>
<td colspan="2">1</td>
</tr>
<tr align="center">
<td colspan="4"><br />0xffffffffffffffff<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4"><br />0xffffffffffffffff<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4"><br />0<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4"><br />1248<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4"><br />8<br /><br /></td>
</tr>
</table>
\code
%h5debug example2.h5 384 96
New address: 384
Reading signature at address 384 (rel)
Tree type ID: H5B_SNODE_ID
Size of node: 544
Size of raw (disk) key: 8
Dirty flag: False
Number of initial dirty children: 0
Level: 0
Address of left sibling: UNDEF
Address of right sibling: UNDEF
Number of children (max): 1 (32)
Child 0...
Address: 1248
Left Key:
Heap offset: 0
Name :
Right Key:
Heap offset: 8
Name : Dataset
\endcode
<table border="">
<caption align="top"><strong>Root Group B-tree Symbol Table Node</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td>'S'</td>
<td>'N'</td>
<td>'O'</td>
<td>'D'</td>
</tr>
<tr align="center">
<td>1</td>
<td>0</td>
<td colspan="2">1</td>
</tr>
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<tr align="center">
<td colspan="4">8</td>
</tr>
<tr align="center">
<td colspan="4"><br />976<br /><br /></td>
</tr>
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4">0</td>
</tr>
<tr align="center">
<td colspan="4"><br /><br />0<br /><br /><br /></td>
</tr>
</table>
</td>
</tr>
</table>
\code
%h5debug example2.h5 1248 96
New address: 1248
Reading signature at address 1248 (rel)
Symbol Table Node...
Dirty: No
Size of Node (in bytes): 328
Number of Symbols: 1 of 8
Symbol 0:
Name: `Dataset'
Name offset into private heap: 8
Object header address: 976
Dirty: No
Cache info type: Nothing Cached
\endcode
<table border="">
<caption align="top"><strong>'/Dataset' Object Header</strong></caption>
<tr align="center">
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
<th width="25%">byte</th>
</tr>
<tr align="center">
<td ><em>Version:</em> 1</td>
<td ><em>Reserved:</em> 0</td>
<td colspan="2"><em>Number of Header Messages:</em> 6</td>
</tr>
<tr align="center">
<td colspan="4"><em>Object Reference Count:</em> 1</td>
</tr>
<tr align="center">
<td colspan="4"><em>Total Object Header Size:</em> 256</td>
</tr>
<!-- Fill Value Header Message -->
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<caption align="top" color="#80FFFF"><em>Fill Value Header Message</em></caption>
<tr align="center">
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
</tr>
<tr align="center">
<!-- Object Header Message Type -->
<td colspan="2"><em>Message Type:</em> 0x0005</td>
<!-- Object Header Message Length -->
<td colspan="2"><em>Message Data Size:</em> 8</td>
</tr>
<tr align="center">
<!-- Object Header Message Flags -->
<td><em>Flags:</em> 0x01</td>
<!-- Reserved -->
<td colspan="3"><em>Reserved:</em> 0</td>
</tr>
<tr align="center">
<!-- Version -->
<td><em>Version:</em> 1</td>
<!-- Space Allocation Time -->
<td><em>Space Allocation Time:</em> 2 (Late)</td>
<!-- Fill Value Writing Time -->
<td><em>Fill Value Writing Time:</em> 0 (At allocation)</td>
<!-- Fill Value Defined -->
<td><em>Fill Value Defined:</em> 0 (Undefined)</td>
</tr>
<tr align="center">
<!-- Fill Value Datatype Size -->
<td colspan="4"><em>Fill Value Datatype Size:</em> 0 (Use dataset's datatype for fill-value datatype)</td>
</tr>
</table>
</td>
</tr>
<!-- Datatype Header Message -->
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<caption align="top"><em>Datatype Header Message</em></caption>
<tr align="center">
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
</tr>
<tr align="center">
<!-- Object Header Message Type -->
<td colspan="2"><em>Message Type:</em> 0x0003</td>
<!-- Object Header Message Length -->
<td colspan="2"><em>Message Data Size:</em> 16</td>
</tr>
<tr align="center">
<!-- Object Header Message Flags -->
<td><em>Flags:</em> 0x01</td>
<!-- Reserved -->
<td colspan="3"><em>Reserved:</em> 0</td>
</tr>
<tr align="center">
<!-- Type Class and Version -->
<td>
<table border="" width="100%">
<tr align="center">
<td width="50%"><em>Version:</em> 0x1</td>
<td><em>Class:</em> 0x0 (Fixed-Point)</td>
</tr>
</table>
</td>
<!-- Class Bit Field -->
<td colspan="3"><em>Fixed-Point Bit-Field:</em> 0x08 (Little-endian, No padding, Signed)</td>
</tr>
<tr align="center">
<!-- Type Size (in bytes) -->
<td colspan="4"><em>Size:</em> 4</td>
</tr>
<tr align="center">
<!-- Bit Offset -->
<td colspan="2"><em>Bit Offset:</em> 0</td>
<!-- Bit Precision -->
<td colspan="2"><em>Bit Precision:</em> 32</td>
</tr>
<tr align="center">
<!-- Message alignment filler -->
<td colspan="4"><em>Message Alignment Filler:</em> -</td>
</tr>
</table>
</td>
</tr>
<!-- Dataspace Header Message -->
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<caption align="top"><em>Dataspace Header Message</em></caption>
<tr align="center">
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
</tr>
<tr align="center">
<!-- Object Header Message Type -->
<td colspan="2"><em>Message Type:</em> 0x0001</td>
<!-- Object Header Message Length -->
<td colspan="2"><em>Message Data Size:</em> 8</td>
</tr>
<tr align="center">
<!-- Object Header Message Flags -->
<td><em>Flags:</em> 0x00</td>
<!-- Reserved -->
<td colspan="3"><em>Reserved:</em> 0</td>
</tr>
<tr align="center">
<!-- Version -->
<td><em>Version:</em> 1</td>
<!-- Rank -->
<td><em>Rank:</em> 0 (Scalar)</td>
<!-- Flags -->
<td><em>Flags:</em> 0x00 (No maximum dimensions, no permutation information)</td>
<!-- Reserved -->
<td><em>Reserved:</em> 0</td>
</tr>
<tr align="center">
<!-- Reserved -->
<td colspan="4"><em>Reserved:</em> 0</td>
</tr>
</table>
</td>
</tr>
<!-- Layout Header Message -->
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<caption align="top"><em>Layout Header Message</em></caption>
<tr align="center">
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
</tr>
<tr align="center">
<!-- Object Header Message Type -->
<td colspan="2"><em>Message Type:</em> 0x0008</td>
<!-- Object Header Message Length -->
<td colspan="2"><em>Message Data Size:</em> 24</td>
</tr>
<tr align="center">
<!-- Object Header Message Flags -->
<td><em>Flags:</em> 0x00</td>
<!-- Reserved -->
<td colspan="3"><em>Reserved:</em> 0</td>
</tr>
<tr align="center">
<!-- Version -->
<td><em>Version:</em> 1</td>
<!-- Rank -->
<td><em>Rank:</em> 1 (Dataspace rank+1)</td>
<!-- Class -->
<td><em>Class:</em> 1 (Contiguous)</td>
<!-- Reserved -->
<td><em>Reserved:</em> 0</td>
</tr>
<tr align="center">
<!-- Reserved -->
<td colspan="4"><em>Reserved:</em> 0</td>
</tr>
<tr align="center">
<!-- Address -->
<td colspan="4"><br><em>Address:</em> 0xffffffffffffffff (Undefined)<br><br></td>
</tr>
<tr align="center">
<!-- Layout Dimensions -->
<td colspan="4"><em>Dimension 0 Size:</em> 4 (Datatype size)</td>
</tr>
<tr align="center">
<!-- Message alignment filler -->
<td colspan="4"><em>Message Alignment Filler:</em> -</td>
</tr>
</table>
</td>
</tr>
<!-- Modification Date & Time Header Message -->
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<caption align="top"><em>Modification Date &amp; Time Header Message</em></caption>
<tr align="center">
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
</tr>
<tr align="center">
<!-- Object Header Message Type -->
<td colspan="2"><em>Message Type:</em> 0x0012</td>
<!-- Object Header Message Length -->
<td colspan="2"><em>Message Data Size:</em> 8</td>
</tr>
<tr align="center">
<!-- Object Header Message Flags -->
<td><em>Flags:</em> 0x00</td>
<!-- Reserved -->
<td colspan="3"><em>Reserved:</em> 0</td>
</tr>
<tr align="center">
<!-- Version -->
<td><em>Version:</em> 1</td>
<!-- Reserved -->
<td colspan="3"><em>Reserved:</em> 0</td>
</tr>
<tr align="center">
<!-- Modification time -->
<td colspan="4"><em>Seconds Since Epoch:</em> 1052401700 (2003-05-08 08:48:20 CDT)</td>
</tr>
</table>
</td>
</tr>
<!-- Null Header Message -->
<tr align="center">
<td colspan="4">
<table border="" width="100%">
<caption align="top"><em>Null Header Message</em></caption>
<tr align="center">
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
<th width="25%"></th>
</tr>
<tr align="center">
<td colspan="2"><em>Message Type:</em> 0x0000</td>
<td colspan="2"><em>Message Data Size:</em> 144</td>
</tr>
<tr align="center">
<td><em>Flags:</em> 0x00</td>
<td colspan="3"><em>Reserved:</em> 0</td>
</tr>
</table>
</td>
</tr>
</table>
\code
%h5debug example2.h5 976
New address: 976
Reading signature at address 976 (rel)
Object Header...
Dirty: 0
Version: 1
Header size (in bytes): 16
Number of links: 1
Number of messages (allocated): 6 (32)
Number of chunks (allocated): 1 (8)
Chunk 0...
Dirty: 0
Address: 992
Size in bytes: 256
Message 0...
Message ID (sequence number): 0x0005 `fill_new' (0)
Shared: No
Constant: Yes
Raw size in obj header: 8 bytes
Chunk number: 0
Message Information:
Version: 1
Space Allocation Time: Late
Fill Time: On Allocation
Fill Value Defined: Undefined
Size: 0
Data type: <dataset type="">
Message 1...
Message ID (sequence number): 0x0003 data_type(0)
Shared message: No
Constant: Yes
Raw size in obj header: 16 bytes
Chunk number: 0
Message Information:
Type class: integer
Size: 4 bytes
Byte order: little endian
Precision: 32 bits
Offset: 0 bits
Low pad type: zero
High pad type: zero
Sign scheme: 2's comp
Message 2...
Message ID (sequence number): 0x0001 simple_dspace(0)
Shared message: No
Constant: No
Raw size in obj header: 8 bytes
Chunk number: 0
Message Information:
Rank: 0
Message 3...
Message ID (sequence number): 0x0008 layout(0)
Shared message: No
Constant: No
Raw size in obj header: 24 bytes
Chunk number: 0
Message Information:
Data address: UNDEF
Number of dimensions: 1
Size: {4}
Message 4...
Message ID (sequence number): 0x0012 mtime_new(0)
Shared message: No
Constant: No
Raw size in obj header: 8 bytes
Chunk number: 0
Message Information:
Time: 2003-03-05 14:52:00 CST
Message 5...
Message ID (sequence number): 0x0000 null(0)
Shared message: No
Constant: No
Raw size in obj header: 144 bytes
Chunk number: 0
Message Information:
<no info="" for="" this="" message="">
\endcode
<hr>
Navigate back: \ref index "Main" / \ref TN
*/
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