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<html>
<head><title>
HDF5/H5F API Specification
</title>
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<a href="index.html">HDF5 documents and links</a> <br>
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And in this document, the
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<h1>H5F: File Interface</h1>
</center>
<h2>File API Functions</h2>
These functions are designed to provide file-level access to HDF5 files.
Further manipulation of objects inside a file is performed through one of APIs
documented below.
<p>
<strong>The C Interfaces:</strong>
<table border=0>
<tr><td valign=top>
<ul>
<li><a href="#File-Create">H5Fcreate</a>
<li><a href="#File-Open">H5Fopen</a>
<li><a href="#File-Reopen">H5Freopen</a>
<li><a href="#File-Close">H5Fclose</a>
</ul>
</td><td> </td><td valign=top>
<ul>
<li><a href="#File-Flush">H5Fflush</a>
<li><a href="#File-IsHDF5">H5Fis_hdf5</a>
<li><a href="#File-Mount">H5Fmount</a>
<li><a href="#File-Unmount">H5Funmount</a>
</ul>
</td><td> </td><td valign=top>
<ul>
<li><a href="#File-GetVfdHandle">H5Fget_vfd_handle</a>
<li><a href="#File-GetCreatePlist">H5Fget_create_plist</a>
<li><a href="#File-GetAccessPlist">H5Fget_access_plist</a>
<li><a href="#File-GetObjCount">H5Fget_obj_count</a>
<li><a href="#File-GetObjIDs">H5Fget_obj_ids</a>
</ul>
</td></tr>
</table>
<br>
<i>Alphabetical Listing</i>
<table border="0">
<tr>
<td valign="top">
<ul>
<li><a href="#File-Close">H5Fclose</a>
<li><a href="#File-Create">H5Fcreate</a>
<li><a href="#File-Flush">H5Fflush</a>
<li><a href="#File-GetAccessPlist">H5Fget_access_plist</a>
<li><a href="#File-GetCreatePlist">H5Fget_create_plist</a>
</ul>
</td>
<td> </td>
<td valign="top">
<ul>
<li><a href="#File-GetObjCount">H5Fget_obj_count</a>
<li><a href="#File-GetObjIDs">H5Fget_obj_ids</a>
<li><a href="#File-GetVfdHandle">H5Fget_vfd_handle</a>
<li><a href="#File-IsHDF5">H5Fis_hdf5</a>
<li><a href="#File-Mount">H5Fmount</a>
</ul>
</td>
<td> </td>
<td valign="top">
<ul>
<li><a href="#File-Open">H5Fopen</a>
<li><a href="#File-Reopen">H5Freopen</a>
<li><a href="#File-Unmount">H5Funmount</a>
</ul>
</td>
</tr>
</table>
<br>
<strong>The FORTRAN90 Interfaces:</strong>
<br>
<font size=-1>
<i>In general, each FORTRAN90 subroutine performs exactly the same task
as the corresponding C function. The links below (electronic versions only) go to the C function
descriptions, which serve as general descriptions for both. A button,
under <strong>Non-C API(s)</strong> at the end of the C function description,
opens an external browser window displaying the FORTRAN90-specific
information. You will probably want to adjust the size and location of
this external window so that both browser windows are visible and to
facilitate moving easily between them.</i>
</font><br>
<table border=0>
<tr><td valign=top>
<ul>
<li><a href="#File-Create">h5fcreate_f</a>
<li><a href="#File-Open">h5fopen_f</a>
<li><a href="#File-Reopen">h5freopen_f</a>
<li><a href="#File-Close">h5fclose_f</a>
</ul>
</td><td> </td><td valign=top>
<ul>
<li><a href="#File-Flush">h5fflush_f</a>
<li><a href="#File-IsHDF5">h5fis_hdf5_f</a>
<li><a href="#File-Mount">h5fmount_f</a>
<li><a href="#File-Unmount">h5funmount_f</a>
</ul>
</td><td> </td><td valign=top>
<ul>
<li><a href="#File-GetVfdHandle">h5fget_vfd_handle_f</a>
<li><a href="#File-GetCreatePlist">h5fget_create_plist_f</a>
<li><a href="#File-GetAccessPlist">h5fget_access_plist_f</a>
<li><a href="#File-GetObjCount">h5fget_obj_count_f</a>
<li><a href="#File-GetObjIDs">h5fget_obj_ids_f</a>
</ul>
</td></tr>
</table>
<!-- NEW PAGE -->
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fclose" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-Close">H5Fclose</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t </em><code>H5Fclose</code>(<em>hid_t</em> <code>file_id</code>
)
<dt><strong>Purpose:</strong>
<dd>Terminates access to an HDF5 file.
<dt><strong>Description:</strong>
<dd><code>H5Fclose</code> terminates access to an HDF5 file
by flushing all data to storage and terminating access
to the file through <code>file_id</code>.
<p>
If this is the last file identifier open for the file
and no other access identifier is open (e.g., a dataset
identifier, group identifier, or shared datatype identifier),
the file will be fully closed and access will end.
<p>
<strong>Delayed close:</strong>
<br>
Note the following deviation from the above-described behavior.
If <code>H5Fclose</code> is called for a file but one or more
objects within the file remain open, those objects will remain
accessible until they are individually closed.
Thus, if the dataset <code>data_sample</code> is open when
<code>H5Fclose</code> is called for the file containing it,
<code>data_sample</code> will remain open and accessible
(including writable) until it is explicitely closed.
The file will be automatically closed once all objects in the
file have been closed.
<p>
Be warned, hoever, that there are circumstances where it is
not possible to delay closing a file.
For example, an MPI-IO file close is a collective call; all of
the processes that opened the file must close it collectively.
The file cannot be closed at some time in the future by each
process in an independent fashion.
Another example is that an application using an AFS token-based
file access privilage may destroy its AFS token after
<code>H5Fclose</code> has returned successfully.
This would make any future access to the file, or any object
within it, illegal.
<p>
In such situations, applications must close all open objects
in a file before calling <code>H5Fclose</code>.
It is generally recommended to do so in all cases.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t</em> <code>file_id</code>
<dd>IN: Identifier of a file to terminate access to.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fclose_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fcreate" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-Create">H5Fcreate</a>
<dt><strong>Signature:</strong>
<dd><em>hid_t </em><code>H5Fcreate</code>(<em>const char *</em><code>name</code>,
<em>unsigned</em> <code>flags</code>,
<em>hid_t</em> <code>create_id</code>,
<em>hid_t</em> <code>access_id</code>
)
<dt><strong>Purpose:</strong>
<dd>Creates HDF5 files.
<dt><strong>Description:</strong>
<dd><code>H5Fcreate</code> is the primary function for creating
HDF5 files .
<p>
The <code>flags</code> parameter determines whether an
existing file will be overwritten. All newly created files
are opened for both reading and writing. All flags may be
combined with the bit-wise OR operator (`|') to change
the behavior of the <code>H5Fcreate</code> call.
<p>
The more complex behaviors of file creation and access
are controlled through the file-creation and file-access
property lists. The value of <code>H5P_DEFAULT</code> for
a property list value indicates that the library should use
the default values for the appropriate property list.
<p>
The return value is a file identifier for the newly-created file;
this file identifier should be closed by calling
<code>H5Fclose</code> when it is no longer needed.
<p>
<b>Special case -- File creation in the case of an
already-open file:</b>
<br>
If a file being created is already opened, by either a
previous <code>H5Fopen</code> or <code>H5Fcreate</code> call,
the HDF5 library may or may not detect that the open file and
the new file are the same physical file.
(See <a href="#File-Open"><code>H5Fopen</code></a> regarding
the limitations in detecting the re-opening of an already-open
file.)
<p>
If the library detects that the file is already opened,
<code>H5Fcreate</code> will return a failure, regardless
of the use of <code>H5F_ACC_TRUNC</code>.
<p>
If the library does not detect that the file is already opened
and <code>H5F_ACC_TRUNC</code> is not used,
<code>H5Fcreate</code> will return a failure because the file
already exists. Note that this is correct behavior.
<p>
But if the library does not detect that the file is already
opened and <code>H5F_ACC_TRUNC</code> is used,
<code>H5Fcreate</code> will truncate the existing file
and return a valid file identifier.
Such a truncation of a currently-opened file will almost
certainly result in errors.
While unlikely, the HDF5 library may not be able to detect,
and thus report, such errors.
<p>
Applications should avoid calling <code>H5Fcreate</code>
with an already opened file.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>const char *</em><code>name</code>
<dd>IN: Name of the file to access.
<dt><em>uintn</em> <code>flags</code>
<dd>IN: File access flags. Allowable values are:
<ul><dl>
<dt><code>H5F_ACC_TRUNC</code>
<dd>Truncate file, if it already exists,
erasing all data previously stored in the file.
<dt><code>H5F_ACC_EXCL</code>
<dd>Fail if file already exists.
</dl></ul>
<li><code>H5F_ACC_TRUNC</code> and <code>H5F_ACC_EXCL</code>
are mutually exclusive; use exactly one.
<li>An additional flag, <code>H5F_ACC_DEBUG</code>, prints
debug information. This flag is used only by HDF5 library
developers; <i>it is neither tested nor supported</i>
for use in applications.
<dt><em>hid_t</em> <code>create_id</code>
<dd>IN: File creation property list identifier, used when modifying
default file meta-data.
Use <code>H5P_DEFAULT</code> for default file creation properties.
<dt><em>hid_t</em> <code>access_id</code>
<dd>IN: File access property list identifier.
If parallel file access is desired, this is a collective
call according to the communicator stored in the
<code>access_id</code>.
Use <code>H5P_DEFAULT</code> for default file access properties.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a file identifier if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fcreate_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fflush" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-Flush">H5Fflush</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t </em><code>H5Fflush</code>(<em>hid_t </em><code>object_id</code>,
<em>H5F_scope_t</em> <code>scope</code>
)
<dt><strong>Purpose:</strong>
<dd>Flushes all buffers associated with a file to disk.
<dt><strong>Description:</strong>
<dd><code>H5Fflush</code> causes all buffers associated with a
file to be immediately flushed to disk without removing the
data from the cache.
<p>
<code>object_id</code> can be any object associated with the file,
including the file itself, a dataset, a group, an attribute, or
a named data type.
<p>
<code>scope</code> specifies whether the scope of the flushing
action is global or local. Valid values are
<center>
<table border=0>
<tr><td align=left valign=bottom><code>H5F_SCOPE_GLOBAL</code></td>
<td> </td>
<td align=left valign=bottom>Flushes the entire virtual file.</td></tr>
<tr><td align=left valign=bottom><code>H5F_SCOPE_LOCAL</code></td>
<td></td>
<td align=left valign=bottom>Flushes only the specified file.</td></tr>
</table>
</center>
<dt><strong>Note:</strong>
<dd>HDF5 does not possess full control over buffering.
<code>H5Fflush</code> flushes the internal HDF5 buffers then
asks the operating system (the OS) to flush the system buffers for the
open files. After that, the OS is responsible for ensuring that
the data is actually flushed to disk.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t </em><code>object_id</code>
<dd>IN: Identifier of object used to identify the file.
<dt><em>H5F_scope_t</em> <code>scope</code>
<dd>IN: Specifies the scope of the flushing action.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fflush_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fget_access_plist" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-GetAccessPlist">H5Fget_access_plist</a>
<dt><strong>Signature:</strong>
<dd><em>hid_t </em><code>H5Fget_access_plist</code>(<em>hid_t</em> <code>file_id</code>)
<dt><strong>Purpose:</strong>
<dd>Returns a file access property list identifier.
<dt><strong>Description:</strong>
<dd><code>H5Fget_access_plist</code> returns the
file access property list identifier of the specified file.
<p>
See "File Access Properties" in
<a href="RM_H5P.html">H5P: Property List Interface</a>
in this reference manual and
"File Access Property Lists"
in <a href="Files.html"><cite>Files</cite></a> in the
<cite>HDF5 User's Guide</cite> for
additional information and related functions.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t</em> <code>file_id</code>
<dd>IN: Identifier of file to get access property list of
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a file access property list identifier if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fget_access_plist_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fget_create_plist" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-GetCreatePlist">H5Fget_create_plist</a>
<dt><strong>Signature:</strong>
<dd><em>hid_t </em><code>H5Fget_create_plist</code>(<em>hid_t</em> <code>file_id</code>
)
<dt><strong>Purpose:</strong>
<dd>Returns a file creation property list identifier.
<dt><strong>Description:</strong>
<dd><code>H5Fget_create_plist</code> returns a file creation
property list identifier identifying the creation properties
used to create this file. This function is useful for
duplicating properties when creating another file.
<p>
See "File Creation Properties" in
<a href="RM_H5P.html">H5P: Property List Interface</a>
in this reference manual and
"File Creation Properties"
in <a href="Files.html"><cite>Files</cite></a> in the
<cite>HDF5 User's Guide</cite> for
additional information and related functions.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t</em> <code>file_id</code>
<dd>IN: Identifier of the file to get creation property list of
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a file creation property list identifier if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fget_create_plist_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fget_obj_count" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-GetObjCount">H5Fget_obj_count</a>
<dt><strong>Signature:</strong>
<dd><em>int </em><code>H5Fget_obj_count</code>(<em>hid_t</em> <code>file_id</code>,
<em>unsigned int</em> <code>types</code>
)
<dt><strong>Purpose:</strong>
<dd>Returns the number of open object identifiers for an open file.
<dt><strong>Description:</strong>
<dd>Given the identifier of an open file, <code>file_id</code>,
and the desired object types, <code>types</code>,
<code>H5Fget_obj_count</code> returns the number of
open object identifiers for the file.
<p>
To retrieve a count of open identifiers for open objects in
all HDF5 application files that are currently open,
pass the value <code>H5F_OBJ_ALL</code> in <code>file_id</code>.
<p>
The types of objects to be counted are specified
in <code>types</code> as follows:
<center>
<table width=90% border=0>
<tr><td valign=top>
<code>H5F_OBJ_FILE</code>
</td><td valign=top>
Files only
</td></tr><tr><td valign=top>
<code>H5F_OBJ_DATASET</code>
</td><td valign=top>
Datasets only
</td></tr><tr><td valign=top>
<code>H5F_OBJ_GROUP</code>
</td><td valign=top>
Groups only
</td></tr><tr><td valign=top>
<code>H5F_OBJ_DATATYPE </code>
</td><td valign=top>
Named datatypes only
</td></tr><tr><td valign=top>
<code>H5F_OBJ_ATTR </code>
</td><td valign=top>
Attributes only
</td></tr><tr><td valign=top>
<code>H5F_OBJ_ALL</code>
</td><td valign=top>
All of the above
<br>
(I.e., <code>H5F_OBJ_FILE</code> | <code>H5F_OBJ_DATASET</code> |
<code>H5F_OBJ_GROUP</code> | <code>H5F_OBJ_DATATYPE</code>
| <code>H5F_OBJ_ATTR</code> )
</td></tr>
</table>
</center>
Multiple object types can be combined with the
logical <code>OR</code> operator (<code>|</code>).
For example, the expression <code>(H5F_OBJ_DATASET|H5F_OBJ_GROUP)</code> would call for
datasets and groups.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t</em> <code>file_id</code>
<dd>IN: Identifier of a currently-open HDF5 file or
<code>H5F_OBJ_ALL</code> for all currently-open HDF5 files.
<dt><em>unsigned int</em> <code>types</code>
<dd>IN: Type of object for which identifiers are to be returned.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a the number of open objects if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fget_obj_count_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fget_obj_ids" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-GetObjIDs">H5Fget_obj_ids</a>
<dt><strong>Signature:</strong>
<dd><em>int </em><code>H5Fget_obj_ids</code>(<em>hid_t</em> <code>file_id</code>,
<em>unsigned int</em> <code>types</code>,
<em>int</em> <code>max_objs</code>,
<em>hid_t *</em><code>obj_id_list</code>
)
<dt><strong>Purpose:</strong>
<dd>Returns a list of open object identifiers.
<dt><strong>Description:</strong>
<dd>Given the file identifier <code>file_id</code> and
the type of objects to be identified, <code>types</code>,
<code>H5Fget_obj_ids</code> returns the list of identifiers
for all open HDF5 objects fitting the specified criteria.
<p>
To retrieve identifiers for open objects in all HDF5 application
files that are currently open, pass the value
<code>H5F_OBJ_ALL</code> in <code>file_id</code>.
<p>
The types of object identifiers to be retrieved are specified
in <code>types</code> using the codes listed for the same
parameter in <a href="#File-GetObjCount"><code>H5Fget_obj_count</code></a>
<p>
To retrieve identifiers for all open objects, pass a negative value
for the <code>max_objs</code>.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t</em> <code>file_id</code>
<dd>IN: Identifier of a currently-open HDF5 file or
<code>H5F_OBJ_ALL</code> for all currently-open HDF5 files.
<dt><em>unsigned int</em> <code>types</code>
<dd>IN: Type of object for which identifiers are to be returned.
<dt><em>int</em> <code>max_objs</code>
<dd>IN: Maximum number of object identifiers to place into <code>obj_id_list</code>.
<dt><em>hid_t *</em><code>obj_id_list</code>
<dd>OUT: Pointer to the returned list of open object identifiers.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns number of objects placed into <code>obj_id_list</code> if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fget_obj_ids_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fget_vfd_handle" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-GetVfdHandle">H5Fget_vfd_handle</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t </em><code>H5Fget_vfd_handle</code>(<em>hid_t</em> <code>file_id</code>,
<em>hid_t</em> <code>fapl_id</code>,
<em>void *</em><code>file_handle</code>
)
<dt><strong>Purpose:</strong>
<dd>Returns pointer to the file handle from the virtual file driver.
<dt><strong>Description:</strong>
<dd>Given the file identifier <code>file_id</code> and
the file access property list <code>fapl_id</code>,
<code>H5Fget_vfd_handle</code> returns a pointer to the file handle
from the low-level file driver currently being used by the
HDF5 library for file I/O.
<dt><strong>Notes:</strong>
<dd>Users are not supposed to modify any file through this file handle.
<p>
This file handle is dynamic and is valid only while the file remains
open; it will be invalid if the file is closed and reopened or
opened during a subsequent session.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t</em> <code>file_id</code>
<dd>IN: Identifier of the file to be queried.
<dt><em>hid_t</em> <code>fapl_id</code>
<dd>IN: File access property list identifier.
For most drivers, the value will be <code>H5P_DEFAULT</code>.
For the <code>FAMILY</code> or <code>MULTI</code> drivers,
this value should be defined through the property list
functions:
<code>H5Pset_family_offset</code> for the <code>FAMILY</code>
driver and <code>H5Pset_multi_type</code> for the
<code>MULTI</code> driver.
<dt><em>void *</em><code>file_handle</code>
<dd>OUT: Pointer to the file handle being used by
the low-level virtual file driver.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<!--
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fget_vfd_handle_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
--> <!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fis_hdf5" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-IsHDF5">H5Fis_hdf5</a>
<dt><strong>Signature:</strong>
<dd><em>htri_t </em><code>H5Fis_hdf5</code>(<em>const char *</em><code>name</code>
)
<dt><strong>Purpose:</strong>
<dd>Determines whether a file is in the HDF5 format.
<dt><strong>Description:</strong>
<dd><code>H5Fis_hdf5</code> determines whether a file is in
the HDF5 format.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>const char *</em><code>name</code>
<dd>IN: File name to check format.
</dl>
<dt><strong>Returns:</strong>
<dd>When successful, returns a positive value, for <code>TRUE</code>,
or <code>0</code> (zero), for <code>FALSE</code>.
Otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fis_hdf5_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fmount" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-Mount">H5Fmount</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5Fmount</code>(<em>hid_t</em> <code>loc_id</code>,
<em>const char *</em><code>name</code>,
<em>hid_t</em> <code>child_id</code>,
<em>hid_t</em> <code>plist_id</code>
)
<dt><strong>Purpose:</strong>
<dd>Mounts a file.
<dt><strong>Description:</strong>
<dd><code>H5Fmount</code> mounts the file specified by
<code>child_id</code> onto the group specified by
<code>loc_id</code> and <code>name</code> using
the mount properties <code>plist_id</code>.
<p>
Note that <code>loc_id</code> is either a file or group identifier
and <code>name</code> is relative to <code>loc_id</code>.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t</em> <code>loc_id</code>
<dd>IN: Identifier for of file or group in
which <code>name</code> is defined.
<dt><em>const char *</em><code>name</code>
<dd>IN: Name of the group onto which the
file specified by <code>child_id</code>
is to be mounted.
<dt><em>hid_t</em> <code>child_id</code>
<dd>IN: Identifier of the file to be mounted.
<dt><em>hid_t</em> <code>plist_id</code>
<dd>IN: Identifier of the property list to be used.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fmount_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Fopen" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-Open">H5Fopen</a>
<dt><strong>Signature:</strong>
<dd><em>hid_t </em><code>H5Fopen</code>(<em>const char *</em><code>name</code>,
<em>unsigned</em> <code>flags</code>,
<em>hid_t</em> <code>access_id</code>
)
<dt><strong>Purpose:</strong>
<dd>Opens an existing file.
<dt><strong>Description:</strong>
<dd><code>H5Fopen</code> opens an existing file and is the primary
function for accessing existing HDF5 files.
<p>
The parameter <code>access_id</code> is a file access property
list identifier or <code>H5P_DEFAULT</code> if the
default I/O access parameters are to be used
<p>
The <code>flags</code> argument determines whether writing
to an existing file will be allowed.
The file is opened with read and write permission if
<code>flags</code> is set to <code>H5F_ACC_RDWR</code>.
All flags may be combined with the bit-wise OR operator (`|')
to change the behavior of the file open call.
More complex behaviors of file access are controlled
through the file-access property list.
<p>
The return value is a file identifier for the open file;
this file identifier should be closed by calling
<code>H5Fclose</code> when it is no longer needed.
<p>
<b>Special case -- Multiple opens:</b>
<br>
A file can often be opened with a new <code>H5Fopen</code>
call without closing an already-open identifier established
in a previous <code>H5Fopen</code> or <code>H5Fcreate</code>
call. Each such <code>H5Fopen</code> call will return a
unique identifier and the file can be accessed through any
of these identifiers as long as the identifier remains valid.
In such multiply-opened cases, all the open calls should
use the same <code>flags</code> argument.
<p>
In some cases, such as files on a local Unix file system,
the HDF5 library can detect that a file is multiply opened and
will maintain coherent access among the file identifiers.
<p>
But in many other cases, such as parallel file systems or
networked file systems, it is not always possible to detect
multiple opens of the same physical file.
In such cases, HDF5 will treat the file identifiers
as though they are accessing different files and
will be unable to maintain coherent access.
Errors are likely to result in these cases.
While unlikely, the HDF5 library may not be able to detect,
and thus report, such errors.
<p>
It is generally recommended that applications avoid
multiple opens of the same file.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>const char *</em><code>name</code>
<dd>IN: Name of the file to access.
<dt><em>unsigned</em> <code>flags</code>
<dd>IN: File access flags. Allowable values are:
<ul><dl>
<dt><code>H5F_ACC_RDWR</code>
<dd>Allow read and write access to file.
<dt><code>H5F_ACC_RDONLY</code>
<dd>Allow read-only access to file.
</dl>
<li><code>H5F_ACC_RDWR</code> and <code>H5F_ACC_RDONLY</code>
are mutually exclusive; use exactly one.
<li>An additional flag, <code>H5F_ACC_DEBUG</code>, prints
debug information. This flag is used only by HDF5 library
developers; it is neither tested nor supported
for use in applications.
</ul>
<dt><em>hid_t</em> <code>access_id</code>
<dd>IN: Identifier for the file access properties list.
If parallel file access is desired, this is a collective
call according to the communicator stored in the
<code>access_id</code>.
Use <code>H5P_DEFAULT</code> for default file access properties.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a file identifier if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5fopen_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Freopen" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-Reopen">H5Freopen</a>
<dt><strong>Signature:</strong>
<dd><em>hid_t </em><code>H5Freopen</code>(<em>hid_t</em> <code>file_id</code>
)
<dt><strong>Purpose:</strong>
<dd>Returns a new identifier for a previously-opened HDF5 file.
<dt><strong>Description:</strong>
<dd><code>H5Freopen</code> returns a new file identifier for an
already-open HDF5 file, as specified by <code>file_id</code>.
Both identifiers share caches and other information.
The only difference between the identifiers is that the
new identifier is not mounted anywhere and no files are
mounted on it.
<p>
Note that there is no circumstance under which
<code>H5Freopen</code> can actually open a closed file;
the file must already be open and have an active
<code>file_id</code>. E.g., one cannot close a file with
<code> H5Fclose (file_id) </code> then use
<code> H5Freopen (file_id) </code> to reopen it.
<p>
The new file identifier should be closed by calling
<code>H5Fclose</code> when it is no longer needed.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t</em> <code>file_id</code>
<dd>IN: Identifier of a file for which an additional identifier
is required.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a new file identifier if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5freopen_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Funmount" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="File-Unmount">H5Funmount</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5Funmount</code>(<em>hid_t</em> <code>loc_id</code>,
<em>const char *</em><code>name</code>
)
<dt><strong>Purpose:</strong>
<dd>Unmounts a file.
<dt><strong>Description:</strong>
<dd>Given a mount point, <code>H5Funmount</code>
dissassociates the mount point's file
from the file mounted there. This function
does not close either file.
<p>
The mount point can be either the group in the
parent or the root group of the mounted file
(both groups have the same name). If the mount
point was opened before the mount then it is the
group in the parent; if it was opened after the
mount then it is the root group of the child.
<p>
Note that <code>loc_id</code> is either a file or group identifier
and <code>name</code> is relative to <code>loc_id</code>.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>hid_t</em> <code>loc_id</code>
<dd>IN: File or group identifier for the location at which
the specified file is to be unmounted.
<dt><em>const char *</em><code>name</code>
<dd>IN: Name of the mount point.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
<dd><a href="fortran/h5f_FORTRAN.html#h5funmount_f"
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
<!--
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
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<table border=0 width=98%>
<tr><td valign=top align=left>
<a href="index.html">HDF5 documents and links</a> <br>
<a href="H5.intro.html">Introduction to HDF5</a> <br>
<a href="http://hdf.ncsa.uiuc.edu/HDF5/doc/UG/index.html">HDF5 User Guide</a> <br>
<!--
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<td valign=top align=right>
And in this document, the
<a href="RM_H5Front.html">HDF5 Reference Manual</a>
<br>
<a href="RM_H5.html">H5</a>
<a href="RM_H5A.html">H5A</a>
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<a href="RM_H5P.html">H5P</a>
<br>
<a href="RM_H5R.html">H5R</a>
<a href="RM_H5S.html">H5S</a>
<a href="RM_H5T.html">H5T</a>
<a href="RM_H5Z.html">H5Z</a>
<a href="Tools.html">Tools</a>
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<a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a>
<br>
Describes HDF5 Release 1.6.0, July 2003
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