H5Fopen
(const char *name
,
unsigned flags
,
hid_t access_id
)
H5Fopen
opens an existing file and is the primary
function for accessing existing HDF5 files.
Note that H5Fopen
does not create a file
if it does not already exist.
See H5Fcreate
.
The parameter access_id
is a file access property
list identifier or H5P_DEFAULT
if the
default I/O access parameters are to be used
The flags
argument determines whether writing
to an existing file will be allowed.
The file is opened with read and write permission if
flags
is set to H5F_ACC_RDWR
.
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.
The return value is a file identifier for the open file;
this file identifier should be closed by calling
H5Fclose
when it is no longer needed.
Special case -- Multiple opens:
A file can often be opened with a new H5Fopen
call without closing an already-open identifier established
in a previous H5Fopen
or H5Fcreate
call. Each such H5Fopen
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 flags
argument.
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.
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.
It is generally recommended that applications avoid multiple opens of the same file.
const char *name |
IN: Name of the file to access. |
unsigned flags |
IN: File access flags. Allowable values are:
|
hid_t access_id |
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
access_id .
Use H5P_DEFAULT for default file access properties. |
SUBROUTINE h5fopen_f(name, access_flags, file_id, hdferr, & access_prp) IMPLICIT NONE CHARACTER(LEN=*), INTENT(IN) :: name ! Name of the file INTEGER, INTENT(IN) :: access_flag ! File access flags ! Possible values are: ! H5F_ACC_RDWR_F ! H5F_ACC_RDONLY_F INTEGER(HID_T), INTENT(OUT) :: file_id ! File identifier INTEGER, INTENT(OUT) :: hdferr ! Error code ! 0 on success and -1 on failure INTEGER(HID_T), OPTIONAL, INTENT(IN) :: access_prp ! File access property list ! identifier END SUBROUTINE h5fopen_f