doc/asn.xml

   1 <!-- $Header: /home/cvsroot/yaz/doc/asn.xml,v 1.3 2001-07-19 16:53:02 adam Exp $ -->
   2 <chapter><title>The ASN Module</title>
   3 <sect1><title>Introduction</title>
   4 <para>
   5 The &asn; module provides you with a set of C struct definitions for the
   6 various PDUs of the protocol, as well as for the complex types
   7 appearing within the PDUs. For the primitive data types, the C
   8 representation often takes the form of an ordinary C language type,
   9 such as <literal>int</literal>. For ASN.1 constructs that have no direct
  10 representation in C, such as general octet strings and bit strings,
  11 the &odr; module (see section <link linkend="odr">The ODR Module</link>)
  12 provides auxiliary definitions.
  13 </para>
  14 </sect1>
  15 <sect1><title>Preparing PDUs</title>
  16
  17 <para>
  18 A structure representing a complex ASN.1 type doesn't in itself contain the
  19 members of that type. Instead, the structure contains
  20 <emphasis>pointers</emphasis> to the members of the type.
  21 This is necessary, in part, to allow a mechanism for specifying which
  22 of the optional structure (SEQUENCE) members are present, and which
  23 are not. It follows that you will need to somehow provide space for
  24 the individual members of the structure, and set the pointers to
  25 refer to the members.
  26 </para>
  27 <para>
  28 The conversion routines don't care how you allocate and maintain your
  29 C structures - they just follow the pointers that you provide.
  30 Depending on the complexity of your application, and your personal
  31 taste, there are at least three different approaches that you may take
  32 when you allocate the structures.
  33 </para>
  34
  35 <para>
  36 You can use static or automatic local variables in the function that
  37 prepares the PDU. This is a simple approach, and it provides the most
  38 efficient form of memory management. While it works well for flat
  39 PDUs like the InitReqest, it will generally not be sufficient for say,
  40 the generation of an arbitrarily complex RPN query structure.
  41 </para>
  42 <para>
  43 You can individually create the structure and its members using the
  44 <function>malloc(2)</function> function. If you want to ensure that
  45 the data is freed when it is no longer needed, you will have to
  46 define a function that individually releases each member of a
  47 structure before freeing the structure itself.
  48 </para>
  49 <para>
  50 You can use the <function>odr_malloc()</function> function (see section
  51 <link linkend="odr-use">Using ODR</link> for details). When you use
  52 <function>odr_malloc()</function>, you can release all of the
  53 allocated data in a single operation, independent of any pointers and
  54 relations between the data. <function>odr_malloc()</function> is based on a
  55 &quot;nibble-memory&quot;
  56 scheme, in which large portions of memory are allocated, and then
  57 gradually handed out with each call to <function>odr_malloc()</function>.
  58 The next time you call <function>odr_reset()</function>, all of the
  59 memory allocated since the last call is recycled for future use (actually,
  60 it is placed on a free-list).
  61 </para>
  62 <para>
  63 You can combine all of the methods described here. This will often be
  64 the most practical approach. For instance, you might use
  65 <function>odr_malloc()</function> to allocate an entire structure and
  66 some of its elements, while you leave other elements pointing to global
  67 or per-session default variables.
  68 </para>
  69
  70 <para>
  71 The &asn; module provides an important aid in creating new PDUs. For
  72 each of the PDU types (say, <function>Z_InitRequest</function>), a
  73 function is provided that allocates and initializes an instance of
  74 that PDU type for you. In the case of the InitRequest, the function is
  75 simply named <function>zget_InitRequest()</function>, and it sets up
  76 reasonable default value for all of the mandatory members. The optional
  77 members are generally initialized to null pointers. This last aspect
  78 is very important: it ensures that if the PDU definitions are
  79 extended after you finish your implementation (to accommodate
  80 new versions of the protocol, say), you won't get into trouble with
  81 uninitialized pointers in your structures. The functions use
  82 <function>odr_malloc()</function> to
  83 allocate the PDUs and its members, so you can free everything again with a
  84 single call to <function>odr_reset()</function>. We strongly recommend
  85 that you use the <literal>zget_*</literal>
  86 functions whenever you are preparing a PDU (in a C++ API, the
  87 <literal>zget_</literal>
  88 functions would probably be promoted to constructors for the
  89 individual types).
  90 </para>
  91 <para>
  92 The prototype for the individual PDU types generally look like this:
  93 </para>
  94 <synopsis>
  95   Z_&lt;type> *zget_&lt;type>(ODR o);
  96 </synopsis>
  97
  98 <para>
  99 eg.:
 100 </para>
 101
 102 <synopsis>
 103   Z_InitRequest *zget_InitRequest(ODR o);
 104 </synopsis>
 105
 106 <para>
 107 The &odr; handle should generally be your encoding stream, but it needn't be.
 108 </para>
 109 <para>
 110 As well as the individual PDU functions, a function <function>
 111 zget_APDU()</function> is
 112 provided, which allocates a toplevel Z-APDU of the type requested:
 113 </para>
 114
 115 <synopsis>
 116   Z_APDU *zget_APDU(ODR o, int which);
 117 </synopsis>
 118
 119 <para>
 120 The <varname>which</varname> parameter is (of course) the discriminator
 121 belonging to the <varname>Z_APDU</varname> <literal>CHOICE</literal> type.
 122 All of the interface described here is provided by the &asn; module, and
 123 you access it through the <filename>proto.h</filename> header file.
 124
 125 </para>
 126 </sect1>
 127 <sect1><title id="oid">Object Identifiers</title>
 128 <para>
 129 When you refer to object identifiers in your application, you need to
 130 be aware that SR and Z39.50 use two different set of OIDs to refer to
 131 the same objects. To handle this easily, &yaz; provides a utility module
 132 to &asn; which provides an internal representation of the OIDs used in
 133 both protocols. Each oid is described by a structure:
 134 </para>
 135
 136 <screen>
 137 typedef struct oident
 138 {
 139     enum oid_proto proto;
 140     enum oid_class class;
 141     enum oid_value value;
 142     int oidsuffix[OID_SIZE];
 143     char *desc;
 144 } oident;
 145 </screen>
 146
 147 <para>
 148 The <literal>proto</literal> field can be set to either
 149 <literal>PROTO_SR</literal> or <literal>PROTO_Z3950</literal>.
 150 The <literal>class</literal> might be, say,
 151 <literal>CLASS_RECSYN</literal>, and the <literal>value</literal> might be
 152 <literal>VAL_USMARC</literal> for the USMARC record format. Functions
 153 </para>
 154
 155 <screen>
 156 int *oid_ent_to_oid(struct oident *ent, int *dst);
 157 struct oident *oid_getentbyoid(int *o);
 158 </screen>
 159
 160 <para>
 161 are provided to map between object identifiers and database entries.
 162 If you store a member of the <literal>oid_proto</literal> type in
 163 your association state information, it's a simple matter, at runtime,
 164 to generate the correct OID when you need it. For decoding, you can
 165 simply ignore the proto field, or if you're strict, you can verify
 166 that your peer is using the OID family from the correct protocol.
 167 The <literal>desc</literal> field is a short, human-readable name
 168 for the PDU, useful mainly for diagnostic output.
 169 </para>
 170
 171 <note>
 172 <para>
 173 The old function <function>oid_getoidbyent</function> still exists but is
 174 not thread safe. Use <function>oid_ent_to_oid</function> instead
 175 and pass an array of size <literal>OID_SIZE</literal>.
 176 </para>
 177 </note>
 178
 179 <note>
 180 <para>
 181 Plans are underway to merge the two protocols into a single
 182 definition, with one set of object identifiers. When this happens, the
 183 oid module will no longer be required to support protocol
 184 independence, but it should still be useful as a simple OID database.
 185 </para>
 186 </note>
 187
 188 </sect1>
 189 <sect1><title>EXTERNAL Data</title>
 190
 191 <para>
 192 In order to achieve extensibility and adaptability to different
 193 application domains, the new version of the protocol defines many
 194 structures outside of the main ASN.1 specification, referencing them
 195 through ASN.1 EXTERNAL constructs. To simplify the construction and access
 196 to the externally referenced data, the &asn; module defines a
 197 specialized version of the EXTERNAL construct, called
 198 <literal>Z_External</literal>.It is defined thus:
 199 </para>
 200
 201 <screen>
 202 typedef struct Z_External
 203 {
 204     Odr_oid *direct_reference;
 205     int *indirect_reference;
 206     char *descriptor;
 207     enum
 208     {
 209         /* Generic types */
 210         Z_External_single = 0,
 211         Z_External_octet,
 212         Z_External_arbitrary,
 213
 214         /* Specific types */
 215         Z_External_SUTRS,
 216         Z_External_explainRecord,
 217         Z_External_resourceReport1,
 218         Z_External_resourceReport2
 219
 220         ...
 221
 222     } which;
 223     union
 224     {
 225         /* Generic types */
 226         Odr_any *single_ASN1_type;
 227         Odr_oct *octet_aligned;
 228         Odr_bitmask *arbitrary;
 229
 230         /* Specific types */
 231         Z_SUTRS *sutrs;
 232         Z_ExplainRecord *explainRecord;
 233         Z_ResourceReport1 *resourceReport1;
 234         Z_ResourceReport2 *resourceReport2;
 235
 236         ...
 237
 238     } u;
 239 } Z_External;
 240 </screen>
 241
 242 <para>
 243 When decoding, the &asn; module will attempt to determine which
 244 syntax describes the data by looking at the reference fields
 245 (currently only the direct-reference). For ASN.1 structured data, you
 246 need only consult the <literal>which</literal> field to determine the type of
 247 data. You can the access  the data directly through the union. When
 248 constructing data for encoding, you set the union pointer to point to
 249 the data, and set the <literal>which</literal> field accordingly.
 250 Remember also to set the direct (or indirect) reference to the correct
 251 OID for the data type.
 252 For non-ASN.1 data such as MARC records, use the
 253 <literal>octet_aligned</literal> arm of the union.
 254 </para>
 255
 256 <para>
 257 Some servers return ASN.1 structured data values (eg. database
 258 records) as BER-encoded records placed in the <literal>octet-aligned</literal>
 259 branch of the EXTERNAL CHOICE. The ASN-module will <emphasis>not</emphasis>
 260 automatically decode these records. To help you decode the records in
 261 the application, the function
 262 </para>
 263
 264 <screen>
 265 Z_ext_typeent *z_ext_gettypebyref(oid_value ref);
 266 </screen>
 267
 268 <para>
 269 Can be used to retrieve information about the known, external data
 270 types. The function return a pointer to a static area, or NULL, if no
 271 match for the given direct reference is found. The
 272 <literal>Z_ext_typeent</literal>
 273 is defined as:
 274 </para>
 275
 276 <screen>
 277 typedef struct Z_ext_typeent
 278 {
 279     oid_value dref;    /* the direct-reference OID value. */
 280     int what;          /* discriminator value for the external CHOICE */
 281     Odr_fun fun;       /* decoder function */
 282 } Z_ext_typeent;
 283 </screen>
 284
 285 <para>
 286 The <literal>what</literal> member contains the <literal>Z_External</literal>
 287 union discriminator value for the given type: For the SUTRS record
 288 syntax, the value would be <literal>Z_External_sutrs</literal>.
 289 The <literal>fun</literal> member contains a pointer to the
 290 function which encodes/decodes the given type. Again, for the SUTRS
 291 record syntax, the value of <literal>fun</literal> would be
 292 <literal>z_SUTRS</literal> (a function pointer).
 293 </para>
 294
 295 <para>
 296 If you receive an EXTERNAL which contains an octet-string value that
 297 you suspect of being an ASN.1-structured data value, you can use
 298 <literal>z_ext_gettypebyref</literal> to look for the provided
 299 direct-reference.
 300 If the return value is different from NULL, you can use the provided
 301 function to decode the BER string (see section <link linkend="odr-use">
 302 Using ODR</link>).
 303 </para>
 304
 305 <para>
 306 If you want to <emphasis>send</emphasis> EXTERNALs containing
 307 ASN.1-structured values in the occtet-aligned branch of the CHOICE, this
 308 is possible too. However, on the encoding phase, it requires a somewhat
 309 involved juggling around of the various buffers involved.
 310 </para>
 311 <para>
 312 If you need to add new, externally defined data types, you must update
 313 the struct above, in the source file <filename>prt-ext.h</filename>, as
 314 well as the encoder/decoder in the file <filename>prt-ext.c</filename>.
 315 When changing the latter, remember to update both the <literal>arm</literal>
 316 arrary and the list <literal>type_table</literal>, which drives the CHOICE
 317 biasing that is necessary to tell the different, structured types apart
 318 on decoding.
 319 </para>
 320
 321 <note>
 322 <para>
 323 Eventually, the EXTERNAL processing will most likely
 324 automatically insert the correct OIDs or indirect-refs. First,
 325 however, we need to determine how application-context management
 326 (specifically the presentation-context-list) should fit into the
 327 various modules.
 328 </para>
 329 </note>
 330
 331 </sect1>
 332 <sect1><title>PDU Contents Table</title>
 333
 334 <para>
 335 We include, for reference, a listing of the fields of each top-level
 336 PDU, as well as their default settings.
 337 </para>
 338
 339 <table frame="top"><title>Default settings for PDU Initialize Request</title>
 340 <tgroup cols="3">
 341 <colspec colname="field"></colspec>
 342 <colspec colname="type"></colspec>
 343 <colspec colname="value"></colspec>
 344 <thead>
 345 <row>
 346 <entry>Field</entry>
 347 <entry>Type</entry>
 348 <entry>Default Value</entry>
 349 </row>
 350 </thead>
 351 <tbody>
 352
 353 <row><entry>
 354 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
 355 </entry></row>
 356
 357 <row><entry>
 358 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
 359 </entry></row>
 360
 361 <row><entry>
 362 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
 363 </entry></row>
 364
 365 <row><entry>
 366 preferredMessageSize</entry><entry>int</entry><entry>30*1024
 367 </entry></row>
 368
 369 <row><entry>
 370 maximumRecordSize</entry><entry>int</entry><entry>30*1024
 371 </entry></row>
 372
 373 <row><entry>
 374 idAuthentication</entry><entry>Z_IdAuthentication</entry><entry>NULL
 375 </entry></row>
 376
 377 <row><entry>
 378 implementationId</entry><entry>char*</entry><entry>"YAZ (id=81)"
 379 </entry></row>
 380
 381 <row><entry>
 382 implementationName</entry><entry>char*</entry><entry>"Index Data/YAZ"
 383 </entry></row>
 384
 385 <row><entry>
 386 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
 387 </entry></row>
 388
 389 <row><entry>
 390 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
 391 </entry></row>
 392
 393 <row><entry>
 394 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
 395 </entry></row>
 396
 397 </tbody>
 398 </tgroup>
 399 </table>
 400
 401 <table frame="top"><title>Default settings for PDU Initialize Response</title>
 402 <tgroup cols="3">
 403 <colspec colname="field"></colspec>
 404 <colspec colname="type"></colspec>
 405 <colspec colname="value"></colspec>
 406 <thead>
 407 <row>
 408 <entry>Field</entry>
 409 <entry>Type</entry>
 410 <entry>Default Value</entry>
 411 </row>
 412 </thead>
 413 <tbody>
 414
 415 <row><entry>
 416 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
 417 </entry></row>
 418
 419 <row><entry>
 420 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
 421 </entry></row>
 422
 423 <row><entry>
 424 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
 425 </entry></row>
 426
 427 <row><entry>
 428 preferredMessageSize</entry><entry>int</entry><entry>30*1024
 429 </entry></row>
 430
 431 <row><entry>
 432 maximumRecordSize</entry><entry>int</entry><entry>30*1024
 433 </entry></row>
 434
 435 <row><entry>
 436 result</entry><entry>bool_t</entry><entry>TRUE
 437 </entry></row>
 438
 439 <row><entry>
 440 implementationId</entry><entry>char*</entry><entry>"YAZ (id=81)"
 441 </entry></row>
 442
 443 <row><entry>
 444 implementationName</entry><entry>char*</entry><entry>"Index Data/YAZ"
 445 </entry></row>
 446
 447 <row><entry>
 448 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
 449 </entry></row>
 450
 451 <row><entry>
 452 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
 453 </entry></row>
 454
 455 <row><entry>
 456 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
 457 </entry></row>
 458
 459 </tbody>
 460 </tgroup>
 461 </table>
 462
 463 <table frame="top"><title>Default settings for PDU Search Request</title>
 464 <tgroup cols="3">
 465 <colspec colname="field"></colspec>
 466 <colspec colname="type"></colspec>
 467 <colspec colname="value"></colspec>
 468 <thead>
 469 <row>
 470 <entry>Field</entry>
 471 <entry>Type</entry>
 472 <entry>Default Value</entry>
 473 </row>
 474 </thead>
 475 <tbody>
 476
 477 <row><entry>
 478 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
 479 </entry></row>
 480
 481 <row><entry>
 482 smallSetUpperBound</entry><entry>int</entry><entry>0
 483 </entry></row>
 484
 485 <row><entry>
 486 largeSetLowerBound</entry><entry>int</entry><entry>1
 487 </entry></row>
 488
 489 <row><entry>
 490 mediumSetPresentNumber</entry><entry>int</entry><entry>0
 491 </entry></row>
 492
 493 <row><entry>
 494 replaceIndicator</entry><entry>bool_t</entry><entry>TRUE
 495 </entry></row>
 496
 497 <row><entry>
 498 resultSetName</entry><entry>char *</entry><entry>"default"
 499 </entry></row>
 500
 501 <row><entry>
 502 num_databaseNames</entry><entry>int</entry><entry>0
 503 </entry></row>
 504
 505 <row><entry>
 506 databaseNames</entry><entry>char **</entry><entry>NULL
 507 </entry></row>
 508
 509 <row><entry>
 510 smallSetElementSetNames</entry><entry>Z_ElementSetNames</entry><entry>NULL
 511 </entry></row>
 512
 513 <row><entry>
 514 mediumSetElementSetNames</entry><entry>Z_ElementSetNames</entry><entry>NULL
 515 </entry></row>
 516
 517 <row><entry>
 518 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
 519 </entry></row>
 520
 521 <row><entry>
 522 query</entry><entry>Z_Query</entry><entry>NULL
 523 </entry></row>
 524
 525 <row><entry>
 526 additionalSearchInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
 527 </entry></row>
 528
 529 <row><entry>
 530 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
 531 </entry></row>
 532
 533 </tbody>
 534 </tgroup>
 535 </table>
 536
 537 <screen>
 538 Z_SearchResponse
 539 ----------------
 540 Field                        Type                Default value
 541
 542 referenceId                  Z_ReferenceId       NULL
 543 resultCount                  int                 0
 544 numberOfRecordsReturned      int                 0
 545 nextResultSetPosition        int                 0
 546 searchStatus                 bool_t              TRUE
 547 resultSetStatus              int                 NULL
 548 presentStatus                int                 NULL
 549 records                      Z_Records           NULL
 550 additionalSearchInfo         Z_OtherInformation  NULL
 551 otherInfo                    Z_OtherInformation  NULL
 552 </screen>
 553
 554 <screen>
 555 Z_PresentRequest
 556 ----------------
 557 Field                        Type                Default value
 558
 559 referenceId                  Z_ReferenceId       NULL
 560 resultSetId                  char*               "default"
 561 resultSetStartPoint          int                 1
 562 numberOfRecordsRequested     int                 10
 563 num_ranges                   int                 0
 564 additionalRanges             Z_Range             NULL
 565 recordComposition            Z_RecordComposition NULL
 566 preferredRecordSyntax        Odr_oid             NULL
 567 maxSegmentCount              int                 NULL
 568 maxRecordSize                int                 NULL
 569 maxSegmentSize               int                 NULL
 570 otherInfo                    Z_OtherInformation  NULL
 571 </screen>
 572
 573 <screen>
 574 Z_PresentResponse
 575 -----------------
 576 Field                        Type                Default value
 577
 578 referenceId                  Z_ReferenceId       NULL
 579 numberOfRecordsReturned      int                 0
 580 nextResultSetPosition        int                 0
 581 presentStatus                int                 Z_PRES_SUCCESS
 582 records                      Z_Records           NULL
 583 otherInfo                    Z_OtherInformation  NULL
 584 </screen>
 585
 586 <screen>
 587 Z_DeleteResultSetRequest
 588 ------------------------
 589 Field                        Type                Default value
 590
 591 referenceId                  Z_ReferenceId       NULL
 592 deleteFunction               int                 Z_DeleteRequest_list
 593 num_ids                      int                 0
 594 resultSetList                char**              NULL
 595 otherInfo                    Z_OtherInformation  NULL
 596 </screen>
 597
 598 <screen>
 599 Z_DeleteResultSetResponse
 600 -------------------------
 601 Field                        Type                Default value
 602
 603 referenceId                  Z_ReferenceId       NULL
 604 deleteOperationStatus        int                 Z_DeleteStatus_success
 605 num_statuses                 int                 0
 606 deleteListStatuses           Z_ListStatus**      NULL
 607 numberNotDeleted             int                 NULL
 608 num_bulkStatuses             int                 0
 609 bulkStatuses                 Z_ListStatus        NULL
 610 deleteMessage                char*               NULL
 611 otherInfo                    Z_OtherInformation  NULL
 612 </screen>
 613
 614 <screen>
 615 Z_ScanRequest
 616 -------------
 617 Field                        Type                Default value
 618
 619 referenceId                  Z_ReferenceId       NULL
 620 num_databaseNames            int                 0
 621 databaseNames                char**              NULL
 622 attributeSet                 Odr_oid             NULL
 623 termListAndStartPoint        Z_AttributesPlus... NULL
 624 stepSize                     int                 NULL
 625 numberOfTermsRequested       int                 20
 626 preferredPositionInResponse  int                 NULL
 627 otherInfo                    Z_OtherInformation  NULL
 628 </screen>
 629
 630 <screen>
 631 Z_ScanResponse
 632 --------------
 633 Field                        Type                Default value
 634
 635 referenceId                  Z_ReferenceId       NULL
 636 stepSize                     int                 NULL
 637 scanStatus                   int                 Z_Scan_success
 638 numberOfEntriesReturned      int                 0
 639 positionOfTerm               int                 NULL
 640 entries                      Z_ListEntris        NULL
 641 attributeSet                 Odr_oid             NULL
 642 otherInfo                    Z_OtherInformation  NULL
 643 </screen>
 644
 645 <screen>
 646 Z_TriggerResourceControlRequest
 647 -------------------------------
 648 Field                        Type                Default value
 649
 650 referenceId                  Z_ReferenceId       NULL
 651 requestedAction              int                 Z_TriggerResourceCtrl_resou..
 652 prefResourceReportFormat     Odr_oid             NULL
 653 resultSetWanted              bool_t              NULL
 654 otherInfo                    Z_OtherInformation  NULL
 655 </screen>
 656
 657 <screen>
 658 Z_ResourceControlRequest
 659 ------------------------
 660 Field                        Type                Default value
 661
 662 referenceId                  Z_ReferenceId       NULL
 663 suspendedFlag                bool_t              NULL
 664 resourceReport               Z_External          NULL
 665 partialResultsAvailable      int                 NULL
 666 responseRequired             bool_t              FALSE
 667 triggeredRequestFlag         bool_t              NULL
 668 otherInfo                    Z_OtherInformation  NULL
 669 </screen>
 670
 671 <screen>
 672 Z_ResourceControlResponse
 673 -------------------------
 674 Field                        Type                Default value
 675
 676 referenceId                  Z_ReferenceId       NULL
 677 continueFlag                 bool_t              TRUE
 678 resultSetWanted              bool_t              NULL
 679 otherInfo                    Z_OtherInformation  NULL
 680 </screen>
 681
 682 <screen>
 683 Z_AccessControlRequest
 684 ----------------------
 685 Field                        Type                Default value
 686
 687 referenceId                  Z_ReferenceId       NULL
 688 which                        enum                Z_AccessRequest_simpleForm;
 689 u                            union               NULL
 690 otherInfo                    Z_OtherInformation  NULL
 691 </screen>
 692
 693 <screen>
 694 Z_AccessControlResponse
 695 -----------------------
 696 Field                        Type                Default value
 697
 698 referenceId                  Z_ReferenceId       NULL
 699 which                        enum                Z_AccessResponse_simpleForm
 700 u                            union               NULL
 701 diagnostic                   Z_DiagRec           NULL
 702 otherInfo                    Z_OtherInformation  NULL
 703 </screen>
 704
 705 <screen>
 706 Z_Segment
 707 ---------
 708 Field                        Type                Default value
 709
 710 referenceId                  Z_ReferenceId       NULL
 711 numberOfRecordsReturned      int                 value=0
 712 num_segmentRecords           int                 0
 713 segmentRecords               Z_NamePlusRecord    NULL
 714 otherInfo                    Z_OtherInformation  NULL
 715 </screen>
 716
 717 <screen>
 718 Z_Close
 719 -------
 720 Field                        Type                Default value
 721
 722 referenceId                  Z_ReferenceId       NULL
 723 closeReason                  int                 Z_Close_finished
 724 diagnosticInformation        char*               NULL
 725 resourceReportFormat         Odr_oid             NULL
 726 resourceFormat               Z_External          NULL
 727 otherInfo                    Z_OtherInformation  NULL
 728
 729 </screen>
 730
 731 </sect1>
 732 </chapter>