1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
2  * Copyright by The HDF Group.                                               *
3  * Copyright by the Board of Trustees of the University of Illinois.         *
4  * All rights reserved.                                                      *
5  *                                                                           *
6  * This file is part of HDF5.  The full HDF5 copyright notice, including     *
7  * terms governing use, modification, and redistribution, is contained in    *
8  * the COPYING file, which can be found at the root of the source code       *
9  * distribution tree, or in https://www.hdfgroup.org/licenses.               *
10  * If you do not have access to either file, you may request a copy from     *
11  * help@hdfgroup.org.                                                        *
12  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
13 
14 /*
15  * Programmer:  Robb Matzke
16  *              Monday, July 26, 1999
17  */
18 #ifndef H5FDpublic_H
19 #define H5FDpublic_H
20 
21 #include "H5public.h"
22 #include "H5Fpublic.h" /*for H5F_close_degree_t */
23 
24 #define H5_HAVE_VFL      1 /*define a convenient app feature test*/
25 #define H5FD_VFD_DEFAULT 0 /* Default VFL driver value */
26 
27 /* Types of allocation requests: see H5Fpublic.h  */
28 typedef enum H5F_mem_t H5FD_mem_t;
29 
30 /* Map "fractal heap" header blocks to 'ohdr' type file memory, since its
31  * a fair amount of work to add a new kind of file memory and they are similar
32  * enough to object headers and probably too minor to deserve their own type.
33  *
34  * Map "fractal heap" indirect blocks to 'ohdr' type file memory, since they
35  * are similar to fractal heap header blocks.
36  *
37  * Map "fractal heap" direct blocks to 'lheap' type file memory, since they
38  * will be replacing local heaps.
39  *
40  * Map "fractal heap" 'huge' objects to 'draw' type file memory, since they
41  * represent large objects that are directly stored in the file.
42  *
43  *      -QAK
44  */
45 #define H5FD_MEM_FHEAP_HDR      H5FD_MEM_OHDR
46 #define H5FD_MEM_FHEAP_IBLOCK   H5FD_MEM_OHDR
47 #define H5FD_MEM_FHEAP_DBLOCK   H5FD_MEM_LHEAP
48 #define H5FD_MEM_FHEAP_HUGE_OBJ H5FD_MEM_DRAW
49 
50 /* Map "free space" header blocks to 'ohdr' type file memory, since its
51  * a fair amount of work to add a new kind of file memory and they are similar
52  * enough to object headers and probably too minor to deserve their own type.
53  *
54  * Map "free space" serialized sections to 'lheap' type file memory, since they
55  * are similar enough to local heap info.
56  *
57  *      -QAK
58  */
59 #define H5FD_MEM_FSPACE_HDR   H5FD_MEM_OHDR
60 #define H5FD_MEM_FSPACE_SINFO H5FD_MEM_LHEAP
61 
62 /* Map "shared object header message" master table to 'ohdr' type file memory,
63  * since its a fair amount of work to add a new kind of file memory and they are
64  * similar enough to object headers and probably too minor to deserve their own
65  * type.
66  *
67  * Map "shared object header message" indices to 'btree' type file memory,
68  * since they are similar enough to B-tree nodes.
69  *
70  *      -QAK
71  */
72 #define H5FD_MEM_SOHM_TABLE H5FD_MEM_OHDR
73 #define H5FD_MEM_SOHM_INDEX H5FD_MEM_BTREE
74 
75 /* Map "extensible array" header blocks to 'ohdr' type file memory, since its
76  * a fair amount of work to add a new kind of file memory and they are similar
77  * enough to object headers and probably too minor to deserve their own type.
78  *
79  * Map "extensible array" index blocks to 'ohdr' type file memory, since they
80  * are similar to extensible array header blocks.
81  *
82  * Map "extensible array" super blocks to 'btree' type file memory, since they
83  * are similar enough to B-tree nodes.
84  *
85  * Map "extensible array" data blocks & pages to 'lheap' type file memory, since
86  * they are similar enough to local heap info.
87  *
88  *      -QAK
89  */
90 #define H5FD_MEM_EARRAY_HDR       H5FD_MEM_OHDR
91 #define H5FD_MEM_EARRAY_IBLOCK    H5FD_MEM_OHDR
92 #define H5FD_MEM_EARRAY_SBLOCK    H5FD_MEM_BTREE
93 #define H5FD_MEM_EARRAY_DBLOCK    H5FD_MEM_LHEAP
94 #define H5FD_MEM_EARRAY_DBLK_PAGE H5FD_MEM_LHEAP
95 
96 /* Map "fixed array" header blocks to 'ohdr' type file memory, since its
97  * a fair amount of work to add a new kind of file memory and they are similar
98  * enough to object headers and probably too minor to deserve their own type.
99  *
100  * Map "fixed array" data blocks & pages to 'lheap' type file memory, since
101  * they are similar enough to local heap info.
102  *
103  */
104 #define H5FD_MEM_FARRAY_HDR       H5FD_MEM_OHDR
105 #define H5FD_MEM_FARRAY_DBLOCK    H5FD_MEM_LHEAP
106 #define H5FD_MEM_FARRAY_DBLK_PAGE H5FD_MEM_LHEAP
107 
108 /*
109  * A free-list map which maps all types of allocation requests to a single
110  * free list.  This is useful for drivers that don't really care about
111  * keeping different requests segregated in the underlying file and which
112  * want to make most efficient reuse of freed memory.  The use of the
113  * H5FD_MEM_SUPER free list is arbitrary.
114  */
115 #define H5FD_FLMAP_SINGLE                                                                                    \
116     {                                                                                                        \
117         H5FD_MEM_SUPER,     /*default*/                                                                      \
118             H5FD_MEM_SUPER, /*super*/                                                                        \
119             H5FD_MEM_SUPER, /*btree*/                                                                        \
120             H5FD_MEM_SUPER, /*draw*/                                                                         \
121             H5FD_MEM_SUPER, /*gheap*/                                                                        \
122             H5FD_MEM_SUPER, /*lheap*/                                                                        \
123             H5FD_MEM_SUPER  /*ohdr*/                                                                         \
124     }
125 
126 /*
127  * A free-list map which segregates requests into `raw' or `meta' data
128  * pools.
129  */
130 #define H5FD_FLMAP_DICHOTOMY                                                                                 \
131     {                                                                                                        \
132         H5FD_MEM_SUPER,     /*default*/                                                                      \
133             H5FD_MEM_SUPER, /*super*/                                                                        \
134             H5FD_MEM_SUPER, /*btree*/                                                                        \
135             H5FD_MEM_DRAW,  /*draw*/                                                                         \
136             H5FD_MEM_DRAW,  /*gheap*/                                                                        \
137             H5FD_MEM_SUPER, /*lheap*/                                                                        \
138             H5FD_MEM_SUPER  /*ohdr*/                                                                         \
139     }
140 
141 /*
142  * The default free list map which causes each request type to use it's own
143  * free-list.
144  */
145 #define H5FD_FLMAP_DEFAULT                                                                                   \
146     {                                                                                                        \
147         H5FD_MEM_DEFAULT,     /*default*/                                                                    \
148             H5FD_MEM_DEFAULT, /*super*/                                                                      \
149             H5FD_MEM_DEFAULT, /*btree*/                                                                      \
150             H5FD_MEM_DEFAULT, /*draw*/                                                                       \
151             H5FD_MEM_DEFAULT, /*gheap*/                                                                      \
152             H5FD_MEM_DEFAULT, /*lheap*/                                                                      \
153             H5FD_MEM_DEFAULT  /*ohdr*/                                                                       \
154     }
155 
156 /* Define VFL driver features that can be enabled on a per-driver basis */
157 /* These are returned with the 'query' function pointer in H5FD_class_t */
158 /*
159  * Defining H5FD_FEAT_AGGREGATE_METADATA for a VFL driver means that
160  * the library will attempt to allocate a larger block for metadata and
161  * then sub-allocate each metadata request from that larger block.
162  */
163 #define H5FD_FEAT_AGGREGATE_METADATA 0x00000001
164 /*
165  * Defining H5FD_FEAT_ACCUMULATE_METADATA for a VFL driver means that
166  * the library will attempt to cache metadata as it is written to the file
167  * and build up a larger block of metadata to eventually pass to the VFL
168  * 'write' routine.
169  *
170  * Distinguish between updating the metadata accumulator on writes and
171  * reads.  This is particularly (perhaps only, even) important for MPI-I/O
172  * where we guarantee that writes are collective, but reads may not be.
173  * If we were to allow the metadata accumulator to be written during a
174  * read operation, the application would hang.
175  */
176 #define H5FD_FEAT_ACCUMULATE_METADATA_WRITE 0x00000002
177 #define H5FD_FEAT_ACCUMULATE_METADATA_READ  0x00000004
178 #define H5FD_FEAT_ACCUMULATE_METADATA                                                                        \
179     (H5FD_FEAT_ACCUMULATE_METADATA_WRITE | H5FD_FEAT_ACCUMULATE_METADATA_READ)
180 /*
181  * Defining H5FD_FEAT_DATA_SIEVE for a VFL driver means that
182  * the library will attempt to cache raw data as it is read from/written to
183  * a file in a "data seive" buffer.  See Rajeev Thakur's papers:
184  *  http://www.mcs.anl.gov/~thakur/papers/romio-coll.ps.gz
185  *  http://www.mcs.anl.gov/~thakur/papers/mpio-high-perf.ps.gz
186  */
187 #define H5FD_FEAT_DATA_SIEVE 0x00000008
188 /*
189  * Defining H5FD_FEAT_AGGREGATE_SMALLDATA for a VFL driver means that
190  * the library will attempt to allocate a larger block for "small" raw data
191  * and then sub-allocate "small" raw data requests from that larger block.
192  */
193 #define H5FD_FEAT_AGGREGATE_SMALLDATA 0x00000010
194 /*
195  * Defining H5FD_FEAT_IGNORE_DRVRINFO for a VFL driver means that
196  * the library will ignore the driver info that is encoded in the file
197  * for the VFL driver.  (This will cause the driver info to be eliminated
198  * from the file when it is flushed/closed, if the file is opened R/W).
199  */
200 #define H5FD_FEAT_IGNORE_DRVRINFO 0x00000020
201 /*
202  * Defining the H5FD_FEAT_DIRTY_DRVRINFO_LOAD for a VFL driver means that
203  * the library will mark the driver info dirty when the file is opened
204  * R/W.  This will cause the driver info to be re-encoded when the file
205  * is flushed/closed.
206  */
207 #define H5FD_FEAT_DIRTY_DRVRINFO_LOAD 0x00000040
208 /*
209  * Defining H5FD_FEAT_POSIX_COMPAT_HANDLE for a VFL driver means that
210  * the handle for the VFD (returned with the 'get_handle' callback) is
211  * of type 'int' and is compatible with POSIX I/O calls.
212  */
213 #define H5FD_FEAT_POSIX_COMPAT_HANDLE 0x00000080
214 /*
215  * Defining H5FD_FEAT_HAS_MPI for a VFL driver means that
216  * the driver makes use of MPI communication and code may retrieve
217  * communicator/rank information from it
218  */
219 #define H5FD_FEAT_HAS_MPI 0x00000100
220 /*
221  * Defining the H5FD_FEAT_ALLOCATE_EARLY for a VFL driver will force
222  * the library to use the H5D_ALLOC_TIME_EARLY on dataset create
223  * instead of the default H5D_ALLOC_TIME_LATE
224  */
225 #define H5FD_FEAT_ALLOCATE_EARLY 0x00000200
226 /*
227  * Defining H5FD_FEAT_ALLOW_FILE_IMAGE for a VFL driver means that
228  * the driver is able to use a file image in the fapl as the initial
229  * contents of a file.
230  */
231 #define H5FD_FEAT_ALLOW_FILE_IMAGE 0x00000400
232 /*
233  * Defining H5FD_FEAT_CAN_USE_FILE_IMAGE_CALLBACKS for a VFL driver
234  * means that the driver is able to use callbacks to make a copy of the
235  * image to store in memory.
236  */
237 #define H5FD_FEAT_CAN_USE_FILE_IMAGE_CALLBACKS 0x00000800
238 /*
239  * Defining H5FD_FEAT_SUPPORTS_SWMR_IO for a VFL driver means that the
240  * driver supports the single-writer/multiple-readers I/O pattern.
241  */
242 #define H5FD_FEAT_SUPPORTS_SWMR_IO 0x00001000
243 /*
244  * Defining H5FD_FEAT_USE_ALLOC_SIZE for a VFL driver
245  * means that the library will just pass the allocation size to the
246  * the driver's allocation callback which will eventually handle alignment.
247  * This is specifically used for the multi/split driver.
248  */
249 #define H5FD_FEAT_USE_ALLOC_SIZE 0x00002000
250 /*
251  * Defining H5FD_FEAT_PAGED_AGGR for a VFL driver
252  * means that the driver needs special file space mapping for paged aggregation.
253  * This is specifically used for the multi/split driver.
254  */
255 #define H5FD_FEAT_PAGED_AGGR 0x00004000
256 /*
257  * Defining H5FD_FEAT_DEFAULT_VFD_COMPATIBLE for a VFL driver
258  * that creates a file which is compatible with the default VFD.
259  * Generally, this means that the VFD creates a single file that follows
260  * the canonical HDF5 file format.
261  * Regarding the Splitter VFD specifically, only drivers with this flag
262  * enabled may be used as the Write-Only (W/O) channel driver.
263  */
264 #define H5FD_FEAT_DEFAULT_VFD_COMPATIBLE 0x00008000
265 
266 /* Forward declaration */
267 typedef struct H5FD_t H5FD_t;
268 
269 /* Class information for each file driver */
270 typedef struct H5FD_class_t {
271     const char *       name;
272     haddr_t            maxaddr;
273     H5F_close_degree_t fc_degree;
274     herr_t (*terminate)(void);
275     hsize_t (*sb_size)(H5FD_t *file);
276     herr_t (*sb_encode)(H5FD_t *file, char *name /*out*/, unsigned char *p /*out*/);
277     herr_t (*sb_decode)(H5FD_t *f, const char *name, const unsigned char *p);
278     size_t fapl_size;
279     void *(*fapl_get)(H5FD_t *file);
280     void *(*fapl_copy)(const void *fapl);
281     herr_t (*fapl_free)(void *fapl);
282     size_t dxpl_size;
283     void *(*dxpl_copy)(const void *dxpl);
284     herr_t (*dxpl_free)(void *dxpl);
285     H5FD_t *(*open)(const char *name, unsigned flags, hid_t fapl, haddr_t maxaddr);
286     herr_t (*close)(H5FD_t *file);
287     int (*cmp)(const H5FD_t *f1, const H5FD_t *f2);
288     herr_t (*query)(const H5FD_t *f1, unsigned long *flags);
289     herr_t (*get_type_map)(const H5FD_t *file, H5FD_mem_t *type_map);
290     haddr_t (*alloc)(H5FD_t *file, H5FD_mem_t type, hid_t dxpl_id, hsize_t size);
291     herr_t (*free)(H5FD_t *file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, hsize_t size);
292     haddr_t (*get_eoa)(const H5FD_t *file, H5FD_mem_t type);
293     herr_t (*set_eoa)(H5FD_t *file, H5FD_mem_t type, haddr_t addr);
294     haddr_t (*get_eof)(const H5FD_t *file, H5FD_mem_t type);
295     herr_t (*get_handle)(H5FD_t *file, hid_t fapl, void **file_handle);
296     herr_t (*read)(H5FD_t *file, H5FD_mem_t type, hid_t dxpl, haddr_t addr, size_t size, void *buffer);
297     herr_t (*write)(H5FD_t *file, H5FD_mem_t type, hid_t dxpl, haddr_t addr, size_t size, const void *buffer);
298     herr_t (*flush)(H5FD_t *file, hid_t dxpl_id, hbool_t closing);
299     herr_t (*truncate)(H5FD_t *file, hid_t dxpl_id, hbool_t closing);
300     herr_t (*lock)(H5FD_t *file, hbool_t rw);
301     herr_t (*unlock)(H5FD_t *file);
302     H5FD_mem_t fl_map[H5FD_MEM_NTYPES];
303 } H5FD_class_t;
304 
305 /* A free list is a singly-linked list of address/size pairs. */
306 typedef struct H5FD_free_t {
307     haddr_t             addr;
308     hsize_t             size;
309     struct H5FD_free_t *next;
310 } H5FD_free_t;
311 
312 /*
313  * The main datatype for each driver. Public fields common to all drivers
314  * are declared here and the driver appends private fields in memory.
315  */
316 struct H5FD_t {
317     hid_t               driver_id;     /*driver ID for this file   */
318     const H5FD_class_t *cls;           /*constant class info       */
319     unsigned long       fileno;        /* File 'serial' number     */
320     unsigned            access_flags;  /* File access flags (from create or open) */
321     unsigned long       feature_flags; /* VFL Driver feature Flags */
322     haddr_t             maxaddr;       /* For this file, overrides class */
323     haddr_t             base_addr;     /* Base address for HDF5 data w/in file */
324 
325     /* Space allocation management fields */
326     hsize_t threshold;  /* Threshold for alignment  */
327     hsize_t alignment;  /* Allocation alignment     */
328     hbool_t paged_aggr; /* Paged aggregation for file space is enabled or not */
329 };
330 
331 /**
332  * Define enum for the source of file image callbacks
333  */
334 //! <!-- [H5FD_file_image_op_t_snip] -->
335 typedef enum {
336     H5FD_FILE_IMAGE_OP_NO_OP,
337     H5FD_FILE_IMAGE_OP_PROPERTY_LIST_SET,
338     /**< Passed to the \p image_malloc and \p image_memcpy callbacks when a
339      * file image buffer is to be copied while being set in a file access
340      * property list (FAPL)*/
341     H5FD_FILE_IMAGE_OP_PROPERTY_LIST_COPY,
342     /**< Passed to the \p image_malloc and \p image_memcpy callbacks
343      * when a file image buffer is to be copied when a FAPL is copied*/
344     H5FD_FILE_IMAGE_OP_PROPERTY_LIST_GET,
345     /**<Passed to the \p image_malloc and \p image_memcpy callbacks when
346      * a file image buffer is to be copied while being retrieved from a FAPL*/
347     H5FD_FILE_IMAGE_OP_PROPERTY_LIST_CLOSE,
348     /**<Passed to the \p image_free callback when a file image
349      * buffer is to be released during a FAPL close operation*/
350     H5FD_FILE_IMAGE_OP_FILE_OPEN,
351     /**<Passed to the \p image_malloc and
352      * \p image_memcpy callbackswhen a
353      * file image buffer is to be copied during a file open operation \n
354      * While the file image being opened will typically be copied from a
355      * FAPL, this need not always be the case. For example, the core file
356      * driver, also known as the memory file driver, takes its initial
357      * image from a file.*/
358     H5FD_FILE_IMAGE_OP_FILE_RESIZE,
359     /**<Passed to the \p image_realloc callback when a file driver needs
360      * to resize an image buffer*/
361     H5FD_FILE_IMAGE_OP_FILE_CLOSE
362     /**<Passed to the \p image_free callback when an image buffer is to
363      * be released during a file close operation*/
364 } H5FD_file_image_op_t;
365 //! <!-- [H5FD_file_image_op_t_snip] -->
366 
367 /**
368  * Define structure to hold file image callbacks
369  */
370 //! <!-- [H5FD_file_image_callbacks_t_snip] -->
371 typedef struct {
372     /**
373      * \param[in] size Size in bytes of the file image buffer to allocate
374      * \param[in] file_image_op A value from H5FD_file_image_op_t indicating
375      *                          the operation being performed on the file image
376      *                          when this callback is invoked
377      * \param[in] udata Value passed in in the H5Pset_file_image_callbacks
378      *            parameter \p udata
379      */
380     //! <!-- [image_malloc_snip] -->
381     void *(*image_malloc)(size_t size, H5FD_file_image_op_t file_image_op, void *udata);
382     //! <!-- [image_malloc_snip] -->
383     /**
384      * \param[in] dest Address of the destination buffer
385      * \param[in] src Address of the source buffer
386      * \param[in] file_image_op A value from #H5FD_file_image_op_t indicating
387      *                          the operation being performed on the file image
388      *                          when this callback is invoked
389      * \param[in] udata Value passed in in the H5Pset_file_image_callbacks
390      *            parameter \p udata
391      */
392     //! <!-- [image_memcpy_snip] -->
393     void *(*image_memcpy)(void *dest, const void *src, size_t size, H5FD_file_image_op_t file_image_op,
394                           void *udata);
395     //! <!-- [image_memcpy_snip] -->
396     /**
397      * \param[in] ptr Pointer to the buffer being reallocated
398      * \param[in] file_image_op A value from #H5FD_file_image_op_t indicating
399      *                          the operation being performed on the file image
400      *                          when this callback is invoked
401      * \param[in] udata Value passed in in the H5Pset_file_image_callbacks
402      *            parameter \p udata
403      */
404     //! <!-- [image_realloc_snip] -->
405     void *(*image_realloc)(void *ptr, size_t size, H5FD_file_image_op_t file_image_op, void *udata);
406     //! <!-- [image_realloc_snip] -->
407     /**
408      * \param[in] udata Value passed in in the H5Pset_file_image_callbacks
409      *            parameter \p udata
410      */
411     //! <!-- [image_free_snip] -->
412     herr_t (*image_free)(void *ptr, H5FD_file_image_op_t file_image_op, void *udata);
413     //! <!-- [image_free_snip] -->
414     /**
415      * \param[in] udata Value passed in in the H5Pset_file_image_callbacks
416      *            parameter \p udata
417      */
418     //! <!-- [udata_copy_snip] -->
419     void *(*udata_copy)(void *udata);
420     //! <!-- [udata_copy_snip] -->
421     /**
422      * \param[in] udata Value passed in in the H5Pset_file_image_callbacks
423      *            parameter \p udata
424      */
425     //! <!-- [udata_free_snip] -->
426     herr_t (*udata_free)(void *udata);
427     //! <!-- [udata_free_snip] -->
428     /**
429      * \brief The final field in the #H5FD_file_image_callbacks_t struct,
430      *        provides a pointer to user-defined data. This pointer will be
431      *        passed to the image_malloc, image_memcpy, image_realloc, and
432      *        image_free callbacks. Define udata as NULL if no user-defined
433      *        data is provided.
434      */
435     void *udata;
436 } H5FD_file_image_callbacks_t;
437 //! <!-- [H5FD_file_image_callbacks_t_snip] -->
438 
439 #ifdef __cplusplus
440 extern "C" {
441 #endif
442 
443 /* Function prototypes */
444 H5_DLL hid_t  H5FDregister(const H5FD_class_t *cls);
445 H5_DLL herr_t H5FDunregister(hid_t driver_id);
446 H5_DLL H5FD_t *H5FDopen(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr);
447 H5_DLL herr_t  H5FDclose(H5FD_t *file);
448 H5_DLL int     H5FDcmp(const H5FD_t *f1, const H5FD_t *f2);
449 H5_DLL int     H5FDquery(const H5FD_t *f, unsigned long *flags);
450 H5_DLL haddr_t H5FDalloc(H5FD_t *file, H5FD_mem_t type, hid_t dxpl_id, hsize_t size);
451 H5_DLL herr_t  H5FDfree(H5FD_t *file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, hsize_t size);
452 H5_DLL haddr_t H5FDget_eoa(H5FD_t *file, H5FD_mem_t type);
453 H5_DLL herr_t  H5FDset_eoa(H5FD_t *file, H5FD_mem_t type, haddr_t eoa);
454 H5_DLL haddr_t H5FDget_eof(H5FD_t *file, H5FD_mem_t type);
455 H5_DLL herr_t  H5FDget_vfd_handle(H5FD_t *file, hid_t fapl, void **file_handle);
456 H5_DLL herr_t  H5FDread(H5FD_t *file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, size_t size,
457                         void *buf /*out*/);
458 H5_DLL herr_t  H5FDwrite(H5FD_t *file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, size_t size,
459                          const void *buf);
460 H5_DLL herr_t  H5FDflush(H5FD_t *file, hid_t dxpl_id, hbool_t closing);
461 H5_DLL herr_t  H5FDtruncate(H5FD_t *file, hid_t dxpl_id, hbool_t closing);
462 H5_DLL herr_t  H5FDlock(H5FD_t *file, hbool_t rw);
463 H5_DLL herr_t  H5FDunlock(H5FD_t *file);
464 
465 /* Allows querying a VFD ID for features before the file is opened */
466 H5_DLL herr_t H5FDdriver_query(hid_t driver_id, unsigned long *flags /*out*/);
467 
468 #ifdef __cplusplus
469 }
470 #endif
471 #endif
472