OpenMPI  0.1.1
dss.h
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1 /* -*- C -*-
2  *
3  * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
4  * University Research and Technology
5  * Corporation. All rights reserved.
6  * Copyright (c) 2004-2005 The University of Tennessee and The University
7  * of Tennessee Research Foundation. All rights
8  * reserved.
9  * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
10  * University of Stuttgart. All rights reserved.
11  * Copyright (c) 2004-2005 The Regents of the University of California.
12  * All rights reserved.
13  * $COPYRIGHT$
14  *
15  * Additional copyrights may follow
16  *
17  * $HEADER$
18  */
19 /**
20  * @file
21  *
22  * Data packing subsystem.
23  */
24 
25 #ifndef OPAL_DSS_H_
26 #define OPAL_DSS_H_
27 
28 #include "opal_config.h"
29 
30 
31 #include "opal/dss/dss_types.h"
32 
33 BEGIN_C_DECLS
34 
35 /**
36  * Set the buffer type.
37  *
38  * The pack/unpack functions can work with two types of buffer - fully
39  * described (i.e., every data object is preceeded by an identifier as
40  * to the type of the object) and non-described (i.e., no type
41  * identifier included). This function allows the caller to set the
42  * buffer type to the specified type - the function first checks to
43  * ensure the buffer is empty as the type cannot be changed once
44  * data has already entered the buffer.
45  *
46  * @param *buffer A pointer to the buffer
47  *
48  * @param type The new buffer type
49  *
50  * @retval OPAL_SUCCESS Operation successfully executed
51  *
52  * @retval OPAL_ERROR_VALUE An appropriate error code
53  */
55 
56 /**
57  * Top-level itnerface function to pack one or more values into a
58  * buffer.
59  *
60  * The pack function packs one or more values of a specified type into
61  * the specified buffer. The buffer must have already been
62  * initialized via an OBJ_NEW or OBJ_CONSTRUCT call - otherwise, the
63  * pack_value function will return an error. Providing an unsupported
64  * type flag will likewise be reported as an error.
65  *
66  * Note that any data to be packed that is not hard type cast (i.e.,
67  * not type cast to a specific size) may lose precision when unpacked
68  * by a non-homogeneous recipient. The DSS will do its best to deal
69  * with heterogeneity issues between the packer and unpacker in such
70  * cases. Sending a number larger than can be handled by the recipient
71  * will return an error code (generated by the DSS upon unpacking) via
72  * the RML upon transmission - the DSS cannot detect such errors
73  * during packing.
74  *
75  * @param *buffer A pointer to the buffer into which the value is to
76  * be packed.
77  *
78  * @param *src A void* pointer to the data that is to be packed. Note
79  * that strings are to be passed as (char **) - i.e., the caller must
80  * pass the address of the pointer to the string as the void*. This
81  * allows the DSS to use a single interface function, but still allow
82  * the caller to pass multiple strings in a single call.
83  *
84  * @param num A size_t value indicating the number of values that are
85  * to be packed, beginning at the location pointed to by src. A string
86  * value is counted as a single value regardless of length. The values
87  * must be contiguous in memory. Arrays of pointers (e.g., string
88  * arrays) should be contiguous, although (obviously) the data pointed
89  * to need not be contiguous across array entries.
90  *
91  * @param type The type of the data to be packed - must be one of the
92  * DSS defined data types.
93  *
94  * @retval OPAL_SUCCESS The data was packed as requested.
95  *
96  * @retval OPAL_ERROR(s) An appropriate OPAL error code indicating the
97  * problem encountered. This error code should be handled
98  * appropriately.
99  *
100  * @code
101  * opal_buffer_t *buffer;
102  * int32_t src;
103  *
104  * status_code = opal_dss.pack(buffer, &src, 1, OPAL_INT32);
105  * @endcode
106  */
107 typedef int (*opal_dss_pack_fn_t)(opal_buffer_t *buffer, const void *src,
108  int32_t num_values,
109  opal_data_type_t type);
110 
111 /**
112  * Unpack values from a buffer.
113  *
114  * The unpack function unpacks the next value (or values) of a
115  * specified type from the specified buffer.
116  *
117  * The buffer must have already been initialized via an OBJ_NEW or
118  * OBJ_CONSTRUCT call (and assumedly filled with some data) -
119  * otherwise, the unpack_value function will return an
120  * error. Providing an unsupported type flag will likewise be reported
121  * as an error, as will specifying a data type that DOES NOT match the
122  * type of the next item in the buffer. An attempt to read beyond the
123  * end of the stored data held in the buffer will also return an
124  * error.
125  *
126  * NOTE: it is possible for the buffer to be corrupted and that
127  * the DSS will *think* there is a proper variable type at the
128  * beginning of an unpack region - but that the value is bogus (e.g., just
129  * a byte field in a string array that so happens to have a value that
130  * matches the specified data type flag). Therefore, the data type error check
131  * is NOT completely safe. This is true for ALL unpack functions.
132  *
133  *
134  * Unpacking values is a "destructive" process - i.e., the values are
135  * removed from the buffer, thus reducing the buffer size. It is
136  * therefore not possible for the caller to re-unpack a value from the
137  * same buffer.
138  *
139  * Warning: The caller is responsible for providing adequate memory
140  * storage for the requested data. The opal_dss_peek() function is
141  * provided to assist in meeting this requirement. As noted below, the user
142  * must provide a parameter indicating the maximum number of values that
143  * can be unpacked into the allocated memory. If more values exist in the
144  * buffer than can fit into the memory storage, then the dss will unpack
145  * what it can fit into that location and return an error code indicating
146  * that the buffer was only partially unpacked.
147  *
148  * Note that any data that was not hard type cast (i.e., not type cast
149  * to a specific size) when packed may lose precision when unpacked by
150  * a non-homogeneous recipient. The DSS will do its best to deal with
151  * heterogeneity issues between the packer and unpacker in such
152  * cases. Sending a number larger than can be handled by the recipient
153  * will return an error code (generated by the DSS upon unpacking) via
154  * the RML upon transmission - the DSS cannot detect such errors
155  * during packing.
156  *
157  * @param *buffer A pointer to the buffer from which the value will be
158  * extracted.
159  *
160  * @param *dest A void* pointer to the memory location into which the
161  * data is to be stored. Note that these values will be stored
162  * contiguously in memory. For strings, this pointer must be to (char
163  * **) to provide a means of supporting multiple string
164  * operations. The DSS unpack function will allocate memory for each
165  * string in the array - the caller must only provide adequate memory
166  * for the array of pointers.
167  *
168  * @param *num A pointer to a int32_t value indicating the maximum
169  * number of values that are to be unpacked, beginning at the location
170  * pointed to by src. This is provided to help protect the caller from
171  * memory overrun. Note that a string
172  * value is counted as a single value regardless of length.
173  *
174  * @note The unpack function will return the actual number of values
175  * unpacked in this location.
176  *
177  * @param type The type of the data to be unpacked - must be one of
178  * the DSS defined data types.
179  *
180  * @retval *max_num_values The number of values actually unpacked. In
181  * most cases, this should match the maximum number provided in the
182  * parameters - but in no case will it exceed the value of this
183  * parameter. Note that if you unpack fewer values than are actually
184  * available, the buffer will be in an unpackable state - the dss will
185  * return an error code to warn of this condition.
186  *
187  * @retval OPAL_SUCCESS The next item in the buffer was successfully
188  * unpacked.
189  *
190  * @retval OPAL_ERROR(s) The unpack function returns an error code
191  * under one of several conditions: (a) the number of values in the
192  * item exceeds the max num provided by the caller; (b) the type of
193  * the next item in the buffer does not match the type specified by
194  * the caller; or (c) the unpack failed due to either an error in the
195  * buffer or an attempt to read past the end of the buffer.
196  *
197  * @code
198  * opal_buffer_t *buffer;
199  * int32_t dest;
200  * char **string_array;
201  * int32_t num_values;
202  *
203  * num_values = 1;
204  * status_code = opal_dss.unpack(buffer, (void*)&dest, &num_values, OPAL_INT32);
205  *
206  * num_values = 5;
207  * string_array = malloc(num_values*sizeof(char *));
208  * status_code = opal_dss.unpack(buffer, (void*)(string_array), &num_values, OPAL_STRING);
209  *
210  * @endcode
211  */
212 typedef int (*opal_dss_unpack_fn_t)(opal_buffer_t *buffer, void *dest,
213  int32_t *max_num_values,
214  opal_data_type_t type);
215 
216 /**
217  * Get the type and number of values of the next item in the buffer.
218  *
219  * The peek function looks at the next item in the buffer and returns
220  * both its type and the number of values in the item. This is a
221  * non-destructive function call that does not disturb the buffer, so
222  * it can be called multiple times if desired.
223  *
224  * @param buffer A pointer to the buffer in question.
225  *
226  * @param type A pointer to an opal_data_type_t variable where the
227  * type of the next item in the buffer is to be stored. Caller must
228  * have memory backing this location.
229  *
230  * @param number A pointer to a int32_t variable where the number of
231  * data values in the next item is to be stored. Caller must have
232  * memory backing this location.
233  *
234  * @retval OPAL_SUCCESS Requested info was successfully returned.
235  * @retval OPAL_ERROR(s) An appropriate error code indicating the
236  * problem will be returned. This should be handled appropriately by
237  * the caller.
238  *
239  */
241  opal_data_type_t *type,
242  int32_t *number);
243 
244 /**
245  * Unload the data payload from a buffer.
246  *
247  * The unload function provides the caller with a pointer to the data
248  * payload within the buffer and the size of that payload. This allows
249  * the user to directly access the payload - typically used in the RML
250  * to unload the payload from the buffer for transmission.
251  *
252  * @note This is a destructive operation. While the payload is
253  * undisturbed, the function will clear the buffer's pointers to the
254  * payload. Thus, the buffer and the payload are completely separated,
255  * leaving the caller free to OBJ_RELEASE the buffer.
256  *
257  * @param buffer A pointer to the buffer whose payload is to be
258  * unloaded.
259  *
260  * @param payload The address to a void* pointer that is to be loaded
261  * with the address of the data payload in the buffer.
262  *
263  * @param size The size (in bytes) of the data payload in the buffer.
264  *
265  * @retval OPAL_SUCCESS The request was succesfully completed.
266  *
267  * @retval OPAL_ERROR(s) An appropriate error code indicating the
268  * problem will be returned. This should be handled appropriately by
269  * the caller.
270  *
271  * @code
272  * opal_buffer_t *buffer;
273  * uint8_t *bytes;
274  * int32_t size;
275  *
276  * status_code = opal_dss.unload(buffer, (void**)(&bytes), &size);
277  * OBJ_RELEASE(buffer);
278  * @endcode
279  */
280 typedef int (*opal_dss_unload_fn_t)(opal_buffer_t *buffer,
281  void **payload,
282  int32_t *size);
283 
284 /**
285  * Load a data payload into a buffer.
286  *
287  * The load function allows the caller to replace the payload in a
288  * buffer with one provided by the caller. If a payload already exists
289  * in the buffer, the function will "free" the existing data to
290  * release it, and then replace the data payload with the one provided
291  * by the caller.
292  *
293  * @note The buffer must be allocated in advance via the OBJ_NEW
294  * function call - failing to do so will cause the load function to
295  * return an error code.
296  *
297  * @note The caller is responsible for pre-packing the provided
298  * payload - the load function cannot convert to network byte order
299  * any data contained in the provided payload.
300  *
301  * @param buffer A pointer to the buffer into which lthe payload is to
302  * be loaded.
303  *
304  * @param payload A void* pointer to the payload to be loaded into the
305  * buffer.
306  *
307  * @param size The size (in bytes) of the provided payload.
308  *
309  * @retval OPAL_SUCCESS The request was successfully completed
310  *
311  * @retval OPAL_ERROR(s) An appropriate error code indicating the
312  * problem will be returned. This should be handled appropriately by
313  * the caller.
314  *
315  * @code
316  * opal_buffer_t *buffer;
317  * uint8_t bytes;
318  * int32_t size;
319  *
320  * buffer = OBJ_NEW(opal_buffer_t);
321  * status_code = opal_dss.load(buffer, (void*)(&bytes), size);
322  * @endcode
323  */
324 typedef int (*opal_dss_load_fn_t)(opal_buffer_t *buffer,
325  void *payload,
326  int32_t size);
327 
328 
329 /**
330  * Copy a payload from one buffer to another
331  * This function will append a copy of the payload in one buffer into
332  * another buffer. If the destination buffer is NOT empty, then the
333  * type of the two buffers MUST match or else an
334  * error will be returned. If the destination buffer IS empty, then
335  * its type will be set to that of the source buffer.
336  * NOTE: This is NOT a destructive procedure - the
337  * source buffer's payload will remain intact, as will any pre-existing
338  * payload in the destination's buffer.
339  */
341  opal_buffer_t *src);
342 
343 /**
344  * DSS initialization function.
345  *
346  * In dynamic libraries, declared objects and functions don't get
347  * loaded until called. We need to ensure that the opal_dss function
348  * structure gets loaded, so we provide an "open" call that is
349  * executed as part of the program startup.
350  */
351 OPAL_DECLSPEC int opal_dss_open(void);
352 
353 /**
354  * DSS finalize function
355  */
356 OPAL_DECLSPEC int opal_dss_close(void);
357 
358 
359 /**
360  * Copy a data value from one location to another.
361  *
362  * Since registered data types can be complex structures, the system
363  * needs some way to know how to copy the data from one location to
364  * another (e.g., for storage in the registry). This function, which
365  * can call other copy functions to build up complex data types, defines
366  * the method for making a copy of the specified data type.
367  *
368  * @param **dest The address of a pointer into which the
369  * address of the resulting data is to be stored.
370  *
371  * @param *src A pointer to the memory location from which the
372  * data is to be copied.
373  *
374  * @param type The type of the data to be copied - must be one of
375  * the DSS defined data types.
376  *
377  * @retval OPAL_SUCCESS The value was successfully copied.
378  *
379  * @retval OPAL_ERROR(s) An appropriate error code.
380  *
381  */
382 typedef int (*opal_dss_copy_fn_t)(void **dest, void *src, opal_data_type_t type);
383 
384 /**
385  * Compare two data values.
386  *
387  * Since registered data types can be complex structures, the system
388  * needs some way to know how to compare two data values (e.g., when
389  * trying to order them in some fashion). This function, which
390  * can call other compare functions to build up complex data types, defines
391  * the method for comparing two values of the specified data type.
392  *
393  * @retval -1 Indicates first value is greater than second value
394  * @retval 0 Indicates two values are equal
395  * @retval +1 Indicates second value is greater than first value
396  */
397 typedef int (*opal_dss_compare_fn_t)(const void *value1, const void *value2,
398  opal_data_type_t type);
399 
400 
401 /**
402  * Compute size of data value.
403  *
404  * Since registered data types can be complex structures, the system
405  * needs some way to compute its size. Some of these types, however, involve
406  * variable amounts of storage (e.g., a string!). Hence, a pointer to the
407  * actual object being "sized" needs to be passed as well.
408  *
409  * @param size Address of a size_t value where the size of the data value
410  * (in bytes) will be stored - set to zero in event of error.
411  *
412  * @param *src A pointer to the memory location of the data object. It is okay
413  * for this to be NULL - if NULL, the function must return the size of the object
414  * itself, not including any data contained in its fields.
415  *
416  * @param type The type of the data value - must be one of
417  * the DSS defined data types or an error will be returned.
418  *
419  * @retval OPAL_SUCCESS The value was successfully copied.
420  *
421  * @retval OPAL_ERROR(s) An appropriate error code.
422  */
423 typedef int (*opal_dss_size_fn_t)(size_t *size, void *src, opal_data_type_t type);
424 
425 
426 /**
427  * Print a data value.
428  *
429  * Since registered data types can be complex structures, the system
430  * needs some way to know how to print them (i.e., convert them to a string
431  * representation).
432  *
433  * @retval OPAL_SUCCESS The value was successfully printed.
434  *
435  * @retval OPAL_ERROR(s) An appropriate error code.
436  */
437 typedef int (*opal_dss_print_fn_t)(char **output, char *prefix, void *src, opal_data_type_t type);
438 
439 
440 /**
441  * Print a data value to an output stream for debugging purposes
442  *
443  * Uses the dss.print command to obtain a string version of the data value
444  * and prints it to the designated output stream.
445  *
446  * @retval OPAL_SUCCESS The value was successfully printed.
447  *
448  * @retval OPAL_ERROR(s) An appropriate error code.
449  */
450 typedef int (*opal_dss_dump_fn_t)(int output_stream, void *src, opal_data_type_t type);
451 
452 /**
453  * Set a data value
454  *
455  * Since the data values are stored in an opaque manner, the system needs
456  * a function by which it can set the data value to a specific value. This
457  * is the equivalent to a C++ access function.
458  *
459  * NOTE: this function does NOT allocate any memory. It only sets the value pointer
460  * and type to the specified location and type. Use "copy" if you want dynamic allocation
461  * of storage.
462  *
463  * @retval OPAL_SUCCESS The value was successfully stored
464  *
465  * @retval OPAL_ERROR(s) An appropriate error code.
466  */
467 typedef int (*opal_dss_set_fn_t)(opal_dss_value_t *value, void *new_value, opal_data_type_t type);
468 
469 /**
470  * Get a data value
471  *
472  * Since the data values are stored in an opaque manner, the system needs
473  * a function by which it can get the data value from within the data_value object. This
474  * is the equivalent to a C++ access function.
475  *
476  * NOTE: this function does NOT allocate any memory. It simply points the "data" location
477  * to that of the value, after ensuring that the value's type matches the specified one.
478  * Use "copy" if you want dynamic allocation of memory.
479  *
480  * @retval OPAL_SUCCESS The value was successfully retrieved
481  *
482  * @retval OPAL_ERROR(s) An appropriate error code - usually caused by the specified type
483  * not matching the data type within the stored object.
484  */
485 typedef int (*opal_dss_get_fn_t)(void **data, opal_dss_value_t *value, opal_data_type_t type);
486 
487 /**
488  * Release the storage used by a data value
489  *
490  * Since the data values are stored in an opaque manner, the system needs
491  * a function by which it can release the storage associated with a value
492  * stored in a data value object.
493  */
494 typedef void (*opal_dss_release_fn_t)(opal_dss_value_t *value);
495 
496 /**
497  * Register a set of data handling functions.
498  *
499  * * This function registers a set of data type functions for a specific
500  * type. An integer is returned that should be used a an argument to
501  * future invocations of opal_dss.pack(), opal_dss.unpack(), opal_dss.copy(),
502  * and opal_dss.compare, which
503  * will trigger calls to the appropriate functions. This
504  * is most useful when extending the datatypes that the dss can
505  * handle; pack and unpack functions can nest calls to opal_dss.pack()
506  * / opal_dss.unpack(), so defining small pack/unpack functions can be
507  * used recursively to build larger types (e.g., packing/unpacking
508  * structs can use calls to opal_dss.pack()/unpack() to serialize /
509  * deserialize individual members). This is likewise true for the copy
510  * and compare functions.
511  *
512  * @param release_fn [IN] Function pointer to the release routine
513  * @param pack_fn [IN] Function pointer to the pack routine
514  * @param unpack_fn [IN] Function pointer to the unpack routine
515  * @param copy_fn [IN] Function pointer to copy routine
516  * @param compare_fn [IN] Function pointer to compare routine
517  * @param size_fn [IN] Function pointer to size routine
518  * @param print_fn [IN] Function pointer to print routine
519  * @param structured [IN] Boolean indicator as to whether or not the data is structured. A true
520  * value indicates that this data type is always passed via reference (i.e., a pointer to the
521  * object is passed) as opposed to directly (e.g., the way an int32_t would appear)
522  * @param name [IN] String name for this pair (mainly for debugging)
523  * @param type [OUT] Type number for this registration
524  *
525  * @returns OPAL_SUCCESS upon success
526  *
527  */
529  opal_dss_unpack_fn_t unpack_fn,
530  opal_dss_copy_fn_t copy_fn,
531  opal_dss_compare_fn_t compare_fn,
532  opal_dss_size_fn_t size_fn,
533  opal_dss_print_fn_t print_fn,
534  opal_dss_release_fn_t release_fn,
535  bool structured,
536  const char *name, opal_data_type_t *type);
537 /*
538  * This function looks up the string name corresponding to the identified
539  * data type - used for debugging messages.
540  */
541 typedef char* (*opal_dss_lookup_data_type_fn_t)(opal_data_type_t type);
542 
543 /*
544  * Dump the data type list - used for debugging to see what has been registered
545  */
546 typedef void (*opal_dss_dump_data_types_fn_t)(int output);
547 
548 
549 /**
550  * Base structure for the DSS
551  *
552  * Base module structure for the DSS - presents the required function
553  * pointers to the calling interface.
554  */
555 struct opal_dss_t {
556  opal_dss_set_fn_t set;
557  opal_dss_get_fn_t get;
558  opal_dss_set_buffer_type_fn_t set_buffer_type;
559  opal_dss_pack_fn_t pack;
560  opal_dss_unpack_fn_t unpack;
561  opal_dss_copy_fn_t copy;
562  opal_dss_compare_fn_t compare;
563  opal_dss_size_fn_t size;
564  opal_dss_print_fn_t print;
565  opal_dss_release_fn_t release;
567  opal_dss_unload_fn_t unload;
568  opal_dss_load_fn_t load;
569  opal_dss_copy_payload_fn_t copy_payload;
570  opal_dss_register_fn_t register_type;
571  opal_dss_lookup_data_type_fn_t lookup_data_type;
572  opal_dss_dump_data_types_fn_t dump_data_types;
573  opal_dss_dump_fn_t dump;
574 };
575 typedef struct opal_dss_t opal_dss_t;
576 
577 OPAL_DECLSPEC extern opal_dss_t opal_dss; /* holds dss function pointers */
578 
579 END_C_DECLS
580 
581 #endif /* OPAL_DSS_H */
int(* opal_dss_register_fn_t)(opal_dss_pack_fn_t pack_fn, opal_dss_unpack_fn_t unpack_fn, opal_dss_copy_fn_t copy_fn, opal_dss_compare_fn_t compare_fn, opal_dss_size_fn_t size_fn, opal_dss_print_fn_t print_fn, opal_dss_release_fn_t release_fn, bool structured, const char *name, opal_data_type_t *type)
Register a set of data handling functions.
Definition: dss.h:528
int(* opal_dss_copy_payload_fn_t)(opal_buffer_t *dest, opal_buffer_t *src)
Copy a payload from one buffer to another This function will append a copy of the payload in one buff...
Definition: dss.h:340
int(* opal_dss_get_fn_t)(void **data, opal_dss_value_t *value, opal_data_type_t type)
Get a data value.
Definition: dss.h:485
OPAL_DECLSPEC int opal_dss_open(void)
DSS initialization function.
Definition: dss_open_close.c:180
int(* opal_dss_copy_fn_t)(void **dest, void *src, opal_data_type_t type)
Copy a data value from one location to another.
Definition: dss.h:382
int(* opal_dss_set_fn_t)(opal_dss_value_t *value, void *new_value, opal_data_type_t type)
Set a data value.
Definition: dss.h:467
int(* opal_dss_unload_fn_t)(opal_buffer_t *buffer, void **payload, int32_t *size)
Unload the data payload from a buffer.
Definition: dss.h:280
BEGIN_C_DECLS typedef int(* opal_dss_set_buffer_type_fn_t)(opal_buffer_t *buffer, opal_dss_buffer_type_t type)
Set the buffer type.
Definition: dss.h:54
int(* opal_dss_load_fn_t)(opal_buffer_t *buffer, void *payload, int32_t size)
Load a data payload into a buffer.
Definition: dss.h:324
int(* opal_dss_unpack_fn_t)(opal_buffer_t *buffer, void *dest, int32_t *max_num_values, opal_data_type_t type)
Unpack values from a buffer.
Definition: dss.h:212
Definition: dss_types.h:89
int(* opal_dss_size_fn_t)(size_t *size, void *src, opal_data_type_t type)
Compute size of data value.
Definition: dss.h:423
void(* opal_dss_release_fn_t)(opal_dss_value_t *value)
Release the storage used by a data value.
Definition: dss.h:494
int(* opal_dss_compare_fn_t)(const void *value1, const void *value2, opal_data_type_t type)
Compare two data values.
Definition: dss.h:397
Buffer management types.
int(* opal_dss_print_fn_t)(char **output, char *prefix, void *src, opal_data_type_t type)
Print a data value.
Definition: dss.h:437
Base structure for the DSS.
Definition: dss.h:555
uint8_t opal_dss_buffer_type_t
buffer type
Definition: dss_types.h:148
Structure for holding a buffer to be used with the RML or OOB subsystems.
Definition: dss_types.h:159
int(* opal_dss_dump_fn_t)(int output_stream, void *src, opal_data_type_t type)
Print a data value to an output stream for debugging purposes.
Definition: dss.h:450
OPAL_DECLSPEC int opal_dss_close(void)
DSS finalize function.
Definition: dss_open_close.c:497
int(* opal_dss_peek_next_item_fn_t)(opal_buffer_t *buffer, opal_data_type_t *type, int32_t *number)
Get the type and number of values of the next item in the buffer.
Definition: dss.h:240
int(* opal_dss_pack_fn_t)(opal_buffer_t *buffer, const void *src, int32_t num_values, opal_data_type_t type)
Top-level itnerface function to pack one or more values into a buffer.
Definition: dss.h:107