rpc.subproj/xdr.3

   1 .\" @(#)xdr.3n  2.2 88/08/03 4.0 RPCSRC; from 1.16 88/03/14 SMI
   2 .\" $FreeBSD: src/lib/libc/xdr/xdr.3,v 1.16 2002/12/19 09:40:28 ru Exp $
   3 .\"
   4 .Dd February 16, 1988
   5 .Dt XDR 3
   6 .Os
   7 .Sh NAME
   8 .Nm xdr ,
   9 .Nm xdr_array ,
  10 .Nm xdr_bool ,
  11 .Nm xdr_bytes ,
  12 .Nm xdr_char ,
  13 .Nm xdr_destroy ,
  14 .Nm xdr_double ,
  15 .Nm xdr_enum ,
  16 .Nm xdr_float ,
  17 .Nm xdr_free ,
  18 .Nm xdr_getpos ,
  19 .Nm xdr_hyper ,
  20 .Nm xdr_inline ,
  21 .Nm xdr_int ,
  22 .Nm xdr_long ,
  23 .Nm xdr_longlong_t ,
  24 .Nm xdrmem_create ,
  25 .Nm xdr_opaque ,
  26 .Nm xdr_pointer ,
  27 .Nm xdrrec_create ,
  28 .Nm xdrrec_endofrecord ,
  29 .Nm xdrrec_eof ,
  30 .Nm xdrrec_skiprecord ,
  31 .Nm xdr_reference ,
  32 .Nm xdr_setpos ,
  33 .Nm xdr_short ,
  34 .Nm xdrstdio_create ,
  35 .Nm xdr_string ,
  36 .Nm xdr_u_char ,
  37 .Nm xdr_u_hyper ,
  38 .Nm xdr_u_int ,
  39 .Nm xdr_u_long ,
  40 .Nm xdr_u_longlong_t ,
  41 .Nm xdr_u_short ,
  42 .Nm xdr_union ,
  43 .Nm xdr_vector ,
  44 .Nm xdr_void ,
  45 .Nm xdr_wrapstring
  46 .Nd "library routines for external data representation"
  47 .Sh LIBRARY
  48 .Lb libc
  49 .Sh SYNOPSIS
  50 .In rpc/types.h
  51 .In rpc/xdr.h
  52 .Pp
  53 See
  54 .Sx DESCRIPTION
  55 for function declarations.
  56 .Sh DESCRIPTION
  57 These routines allow C programmers to describe
  58 arbitrary data structures in a machine-independent fashion.
  59 Data for remote procedure calls are transmitted using these
  60 routines.
  61 .Pp
  62 .Bl -tag -width indent -compact
  63 .It Xo
  64 .Ft int
  65 .Xc
  66 .It Xo
  67 .Fo xdr_array
  68 .Fa "XDR *xdrs"
  69 .Fa "char **arrp"
  70 .Fa "u_int *sizep"
  71 .Fa "u_int maxsize"
  72 .Fa "u_int elsize"
  73 .Fa "xdrproc_t elproc"
  74 .Fc
  75 .Xc
  76 .Pp
  77 A filter primitive that translates between variable-length
  78 arrays
  79 and their corresponding external representations.
  80 The
  81 .Fa arrp
  82 argument
  83 is the address of the pointer to the array, while
  84 .Fa sizep
  85 is the address of the element count of the array;
  86 this element count cannot exceed
  87 .Fa maxsize .
  88 The
  89 .Fa elsize
  90 argument
  91 is the
  92 .Ic sizeof
  93 each of the array's elements, and
  94 .Fa elproc
  95 is an
  96 .Tn XDR
  97 filter that translates between
  98 the array elements' C form, and their external
  99 representation.
 100 This routine returns one if it succeeds, zero otherwise.
 101 .Pp
 102 .It Xo
 103 .Ft int
 104 .Xc
 105 .It Xo
 106 .Fn xdr_bool "XDR *xdrs" "bool_t *bp"
 107 .Xc
 108 .Pp
 109 A filter primitive that translates between booleans (C
 110 integers)
 111 and their external representations.
 112 When encoding data, this
 113 filter produces values of either one or zero.
 114 This routine returns one if it succeeds, zero otherwise.
 115 .Pp
 116 .It Xo
 117 .Ft int
 118 .Xc
 119 .It Xo
 120 .Fn xdr_bytes "XDR *xdrs" "char **sp" "u_int *sizep" "u_int maxsize"
 121 .Xc
 122 .Pp
 123 A filter primitive that translates between counted byte
 124 strings and their external representations.
 125 The
 126 .Fa sp
 127 argument
 128 is the address of the string pointer.
 129 The length of the
 130 string is located at address
 131 .Fa sizep ;
 132 strings cannot be longer than
 133 .Fa maxsize .
 134 This routine returns one if it succeeds, zero otherwise.
 135 .Pp
 136 .It Xo
 137 .Ft int
 138 .Xc
 139 .It Xo
 140 .Fn xdr_char "XDR *xdrs" "char *cp"
 141 .Xc
 142 .Pp
 143 A filter primitive that translates between C characters
 144 and their external representations.
 145 This routine returns one if it succeeds, zero otherwise.
 146 Note: encoded characters are not packed, and occupy 4 bytes
 147 each.
 148 For arrays of characters, it is worthwhile to
 149 consider
 150 .Fn xdr_bytes ,
 151 .Fn xdr_opaque
 152 or
 153 .Fn xdr_string .
 154 .Pp
 155 .It Xo
 156 .Ft void
 157 .Xc
 158 .It Xo
 159 .Fn xdr_destroy "XDR *xdrs"
 160 .Xc
 161 .Pp
 162 A macro that invokes the destroy routine associated with the
 163 .Tn XDR
 164 stream,
 165 .Fa xdrs .
 166 Destruction usually involves freeing private data structures
 167 associated with the stream.
 168 Using
 169 .Fa xdrs
 170 after invoking
 171 .Fn xdr_destroy
 172 is undefined.
 173 .Pp
 174 .It Xo
 175 .Ft int
 176 .Xc
 177 .It Xo
 178 .Fn xdr_double "XDR *xdrs" "double *dp"
 179 .Xc
 180 .Pp
 181 A filter primitive that translates between C
 182 .Vt double
 183 precision numbers and their external representations.
 184 This routine returns one if it succeeds, zero otherwise.
 185 .Pp
 186 .It Xo
 187 .Ft int
 188 .Xc
 189 .It Xo
 190 .Fn xdr_enum "XDR *xdrs" "enum_t *ep"
 191 .Xc
 192 .Pp
 193 A filter primitive that translates between C
 194 .Vt enum Ns s
 195 (actually integers) and their external representations.
 196 This routine returns one if it succeeds, zero otherwise.
 197 .Pp
 198 .It Xo
 199 .Ft int
 200 .Xc
 201 .It Xo
 202 .Fn xdr_float "XDR *xdrs" "float *fp"
 203 .Xc
 204 .Pp
 205 A filter primitive that translates between C
 206 .Vt float Ns s
 207 and their external representations.
 208 This routine returns one if it succeeds, zero otherwise.
 209 .Pp
 210 .It Xo
 211 .Ft void
 212 .Xc
 213 .It Xo
 214 .Fn xdr_free "xdrproc_t proc" "char *objp"
 215 .Xc
 216 .Pp
 217 Generic freeing routine.
 218 The first argument is the
 219 .Tn XDR
 220 routine for the object being freed.
 221 The second argument
 222 is a pointer to the object itself.
 223 Note: the pointer passed
 224 to this routine is
 225 .Em not
 226 freed, but what it points to
 227 .Em is
 228 freed (recursively).
 229 .Pp
 230 .It Xo
 231 .Ft u_int
 232 .Xc
 233 .It Xo
 234 .Fn xdr_getpos "XDR *xdrs"
 235 .Xc
 236 .Pp
 237 A macro that invokes the get\-position routine
 238 associated with the
 239 .Tn XDR
 240 stream,
 241 .Fa xdrs .
 242 The routine returns an unsigned integer,
 243 which indicates the position of the
 244 .Tn XDR
 245 byte stream.
 246 A desirable feature of
 247 .Tn XDR
 248 streams is that simple arithmetic works with this number,
 249 although the
 250 .Tn XDR
 251 stream instances need not guarantee this.
 252 .Pp
 253 .It Xo
 254 .Ft int
 255 .Xc
 256 .It Xo
 257 .Fn xdr_hyper "XDR *xdrs" "quad_t *llp"
 258 .Xc
 259 A filter primitive that translates between ANSI C
 260 .Vt "long long"
 261 integers and their external representations.
 262 This routine returns one if it succeeds, zero otherwise.
 263 .Pp
 264 .It Xo
 265 .Ft "long *"
 266 .Xc
 267 .It Xo
 268 .Fn xdr_inline "XDR *xdrs" "int len"
 269 .Xc
 270 .Pp
 271 A macro that invokes the in-line routine associated with the
 272 .Tn XDR
 273 stream,
 274 .Fa xdrs .
 275 The routine returns a pointer
 276 to a contiguous piece of the stream's buffer;
 277 .Fa len
 278 is the byte length of the desired buffer.
 279 Note: pointer is cast to
 280 .Vt "long *" .
 281 .Pp
 282 Warning:
 283 .Fn xdr_inline
 284 may return
 285 .Dv NULL
 286 (0)
 287 if it cannot allocate a contiguous piece of a buffer.
 288 Therefore the behavior may vary among stream instances;
 289 it exists for the sake of efficiency.
 290 .Pp
 291 .It Xo
 292 .Ft int
 293 .Xc
 294 .It Xo
 295 .Fn xdr_int "XDR *xdrs" "int *ip"
 296 .Xc
 297 .Pp
 298 A filter primitive that translates between C integers
 299 and their external representations.
 300 This routine returns one if it succeeds, zero otherwise.
 301 .Pp
 302 .It Xo
 303 .Ft int
 304 .Xc
 305 .It Xo
 306 .Fn xdr_long "XDR *xdrs" "long *lp"
 307 .Xc
 308 .Pp
 309 A filter primitive that translates between C
 310 .Vt long
 311 integers and their external representations.
 312 This routine returns one if it succeeds, zero otherwise.
 313 .Pp
 314 .It Xo
 315 .Ft int
 316 .Xc
 317 .It Xo
 318 .Fn xdr_longlong_t "XDR *xdrs" "quad_t *llp"
 319 .Xc
 320 A filter primitive that translates between ANSI C
 321 .Vt "long long"
 322 integers and their external representations.
 323 This routine returns one if it succeeds, zero otherwise.
 324 .Pp
 325 .It Xo
 326 .Ft void
 327 .Xc
 328 .It Xo
 329 .Fn xdrmem_create "XDR *xdrs" "char *addr" "u_int size" "enum xdr_op op"
 330 .Xc
 331 .Pp
 332 This routine initializes the
 333 .Tn XDR
 334 stream object pointed to by
 335 .Fa xdrs .
 336 The stream's data is written to, or read from,
 337 a chunk of memory at location
 338 .Fa addr
 339 whose length is no more than
 340 .Fa size
 341 bytes long.
 342 The
 343 .Fa op
 344 argument
 345 determines the direction of the
 346 .Tn XDR
 347 stream
 348 (either
 349 .Dv XDR_ENCODE ,
 350 .Dv XDR_DECODE ,
 351 or
 352 .Dv XDR_FREE ) .
 353 .Pp
 354 .It Xo
 355 .Ft int
 356 .Xc
 357 .It Xo
 358 .Fn xdr_opaque "XDR *xdrs" "char *cp" "u_int cnt"
 359 .Xc
 360 .Pp
 361 A filter primitive that translates between fixed size opaque
 362 data
 363 and its external representation.
 364 The
 365 .Fa cp
 366 argument
 367 is the address of the opaque object, and
 368 .Fa cnt
 369 is its size in bytes.
 370 This routine returns one if it succeeds, zero otherwise.
 371 .Pp
 372 .It Xo
 373 .Ft int
 374 .Xc
 375 .It Xo
 376 .Fn xdr_pointer "XDR *xdrs" "char **objpp" "u_int objsize" "xdrproc_t xdrobj"
 377 .Xc
 378 .Pp
 379 Like
 380 .Fn xdr_reference
 381 except that it serializes
 382 .Dv NULL
 383 pointers, whereas
 384 .Fn xdr_reference
 385 does not.
 386 Thus,
 387 .Fn xdr_pointer
 388 can represent
 389 recursive data structures, such as binary trees or
 390 linked lists.
 391 .Pp
 392 .It Xo
 393 .Ft void
 394 .Xc
 395 .It Xo
 396 .Fo xdrrec_create
 397 .Fa "XDR *xdrs"
 398 .Fa "u_int sendsize"
 399 .Fa "u_int recvsize"
 400 .Fa "char *handle"
 401 .Fa "int \*(lp*readit\*(rp\*(lp\*(rp"
 402 .Fa "int \*(lp*writeit\*(rp\*(lp\*(rp"
 403 .Fc
 404 .Xc
 405 .Pp
 406 This routine initializes the
 407 .Tn XDR
 408 stream object pointed to by
 409 .Fa xdrs .
 410 The stream's data is written to a buffer of size
 411 .Fa sendsize ;
 412 a value of zero indicates the system should use a suitable
 413 default.
 414 The stream's data is read from a buffer of size
 415 .Fa recvsize ;
 416 it too can be set to a suitable default by passing a zero
 417 value.
 418 When a stream's output buffer is full,
 419 .Fn writeit
 420 is called.
 421 Similarly, when a stream's input buffer is empty,
 422 .Fn readit
 423 is called.
 424 The behavior of these two routines is similar to
 425 the
 426 system calls
 427 .Xr read 2
 428 and
 429 .Xr write 2 ,
 430 except that
 431 .Fa handle
 432 is passed to the former routines as the first argument.
 433 Note: the
 434 .Tn XDR
 435 stream's
 436 .Fa op
 437 field must be set by the caller.
 438 .Pp
 439 Warning: this
 440 .Tn XDR
 441 stream implements an intermediate record stream.
 442 Therefore there are additional bytes in the stream
 443 to provide record boundary information.
 444 .Pp
 445 .It Xo
 446 .Ft int
 447 .Xc
 448 .It Xo
 449 .Fn xdrrec_endofrecord "XDR *xdrs" "int sendnow"
 450 .Xc
 451 .Pp
 452 This routine can be invoked only on
 453 streams created by
 454 .Fn xdrrec_create .
 455 The data in the output buffer is marked as a completed
 456 record,
 457 and the output buffer is optionally written out if
 458 .Fa sendnow
 459 is non-zero.
 460 This routine returns one if it succeeds, zero
 461 otherwise.
 462 .Pp
 463 .It Xo
 464 .Ft int
 465 .Xc
 466 .It Xo
 467 .Fn xdrrec_eof "XDR *xdrs"
 468 .Xc
 469 .Pp
 470 This routine can be invoked only on
 471 streams created by
 472 .Fn xdrrec_create .
 473 After consuming the rest of the current record in the stream,
 474 this routine returns one if the stream has no more input,
 475 zero otherwise.
 476 .Pp
 477 .It Xo
 478 .Ft int
 479 .Xc
 480 .It Xo
 481 .Fn xdrrec_skiprecord "XDR *xdrs"
 482 .Xc
 483 .Pp
 484 This routine can be invoked only on
 485 streams created by
 486 .Fn xdrrec_create .
 487 It tells the
 488 .Tn XDR
 489 implementation that the rest of the current record
 490 in the stream's input buffer should be discarded.
 491 This routine returns one if it succeeds, zero otherwise.
 492 .Pp
 493 .It Xo
 494 .Ft int
 495 .Xc
 496 .It Xo
 497 .Fn xdr_reference "XDR *xdrs" "char **pp" "u_int size" "xdrproc_t proc"
 498 .Xc
 499 .Pp
 500 A primitive that provides pointer chasing within structures.
 501 The
 502 .Fa pp
 503 argument
 504 is the address of the pointer;
 505 .Fa size
 506 is the
 507 .Ic sizeof
 508 the structure that
 509 .Fa *pp
 510 points to; and
 511 .Fa proc
 512 is an
 513 .Tn XDR
 514 procedure that filters the structure
 515 between its C form and its external representation.
 516 This routine returns one if it succeeds, zero otherwise.
 517 .Pp
 518 Warning: this routine does not understand
 519 .Dv NULL
 520 pointers.
 521 Use
 522 .Fn xdr_pointer
 523 instead.
 524 .Pp
 525 .It Xo
 526 .Ft int
 527 .Xc
 528 .It Xo
 529 .Fn xdr_setpos "XDR *xdrs" "u_int pos"
 530 .Xc
 531 .Pp
 532 A macro that invokes the set position routine associated with
 533 the
 534 .Tn XDR
 535 stream
 536 .Fa xdrs .
 537 The
 538 .Fa pos
 539 argument
 540 is a position value obtained from
 541 .Fn xdr_getpos .
 542 This routine returns one if the
 543 .Tn XDR
 544 stream could be repositioned,
 545 and zero otherwise.
 546 .Pp
 547 Warning: it is difficult to reposition some types of
 548 .Tn XDR
 549 streams, so this routine may fail with one
 550 type of stream and succeed with another.
 551 .Pp
 552 .It Xo
 553 .Ft int
 554 .Xc
 555 .It Xo
 556 .Fn xdr_short "XDR *xdrs" "short *sp"
 557 .Xc
 558 .Pp
 559 A filter primitive that translates between C
 560 .Vt short
 561 integers and their external representations.
 562 This routine returns one if it succeeds, zero otherwise.
 563 .Pp
 564 .It Li "#ifdef _STDIO_H_"
 565 .It Li "/* XDR using stdio library */"
 566 .It Xo
 567 .Ft void
 568 .Xc
 569 .It Xo
 570 .Fn xdrstdio_create "XDR *xdrs" "FILE *file" "enum xdr_op op"
 571 .Xc
 572 .It Li "#endif"
 573 .Pp
 574 This routine initializes the
 575 .Tn XDR
 576 stream object pointed to by
 577 .Fa xdrs .
 578 The
 579 .Tn XDR
 580 stream data is written to, or read from, the Standard
 581 .Tn I/O
 582 stream
 583 .Fa file .
 584 The
 585 .Fa op
 586 argument
 587 determines the direction of the
 588 .Tn XDR
 589 stream (either
 590 .Dv XDR_ENCODE ,
 591 .Dv XDR_DECODE ,
 592 or
 593 .Dv XDR_FREE ) .
 594 .Pp
 595 Warning: the destroy routine associated with such
 596 .Tn XDR
 597 streams calls
 598 .Xr fflush 3
 599 on the
 600 .Fa file
 601 stream, but never
 602 .Xr fclose 3 .
 603 .Pp
 604 .It Xo
 605 .Ft int
 606 .Xc
 607 .It Xo
 608 .Fn xdr_string "XDR *xdrs" "char **sp" "u_int maxsize"
 609 .Xc
 610 .Pp
 611 A filter primitive that translates between C strings and
 612 their
 613 corresponding external representations.
 614 Strings cannot be longer than
 615 .Fa maxsize .
 616 Note:
 617 .Fa sp
 618 is the address of the string's pointer.
 619 This routine returns one if it succeeds, zero otherwise.
 620 .Pp
 621 .It Xo
 622 .Ft int
 623 .Xc
 624 .It Xo
 625 .Fn xdr_u_char "XDR *xdrs" "unsigned char *ucp"
 626 .Xc
 627 .Pp
 628 A filter primitive that translates between
 629 .Vt unsigned
 630 C characters and their external representations.
 631 This routine returns one if it succeeds, zero otherwise.
 632 .Pp
 633 .It Xo
 634 .Ft int
 635 .Xc
 636 .It Xo
 637 .Fn xdr_u_hyper "XDR *xdrs" "u_quad_t *ullp"
 638 .Xc
 639 A filter primitive that translates between
 640 .Vt unsigned
 641 ANSI C
 642 .Vt long long
 643 integers and their external representations.
 644 This routine returns one if it succeeds, zero otherwise.
 645 .Pp
 646 .It Xo
 647 .Ft int
 648 .Xc
 649 .It Xo
 650 .Fn xdr_u_int "XDR *xdrs" "unsigned *up"
 651 .Xc
 652 .Pp
 653 A filter primitive that translates between C
 654 .Vt unsigned
 655 integers and their external representations.
 656 This routine returns one if it succeeds, zero otherwise.
 657 .Pp
 658 .It Xo
 659 .Ft int
 660 .Xc
 661 .It Xo
 662 .Fn xdr_u_long "XDR *xdrs" "unsigned long *ulp"
 663 .Xc
 664 .Pp
 665 A filter primitive that translates between C
 666 .Vt "unsigned long"
 667 integers and their external representations.
 668 This routine returns one if it succeeds, zero otherwise.
 669 .Pp
 670 .It Xo
 671 .Ft int
 672 .Xc
 673 .It Xo
 674 .Fn xdr_u_longlong_t "XDR *xdrs" "u_quad_t *ullp"
 675 .Xc
 676 A filter primitive that translates between
 677 .Vt unsigned
 678 ANSI C
 679 .Vt "long long"
 680 integers and their external representations.
 681 This routine returns one if it succeeds, zero otherwise.
 682 .Pp
 683 .It Xo
 684 .Ft int
 685 .Xc
 686 .It Xo
 687 .Fn xdr_u_short "XDR *xdrs" "unsigned short *usp"
 688 .Xc
 689 .Pp
 690 A filter primitive that translates between C
 691 .Vt "unsigned short"
 692 integers and their external representations.
 693 This routine returns one if it succeeds, zero otherwise.
 694 .Pp
 695 .It Xo
 696 .Ft int
 697 .Xc
 698 .It Xo
 699 .Fo xdr_union
 700 .Fa "XDR *xdrs"
 701 .Fa "enum_t *dscmp"
 702 .Fa "char *unp"
 703 .Fa "const struct xdr_discrim *choices"
 704 .Fa "xdrproc_t defaultarm"
 705 .Fc
 706 .Xc
 707 .Pp
 708 A filter primitive that translates between a discriminated C
 709 .Vt union
 710 and its corresponding external representation.
 711 It first
 712 translates the discriminant of the union located at
 713 .Fa dscmp .
 714 This discriminant is always an
 715 .Vt enum_t .
 716 Next the union located at
 717 .Fa unp
 718 is translated.
 719 The
 720 .Fa choices
 721 argument
 722 is a pointer to an array of
 723 .Vt xdr_discrim
 724 structures.
 725 Each structure contains an ordered pair of
 726 .Bq Va value , proc .
 727 If the union's discriminant is equal to the associated
 728 .Va value ,
 729 then the
 730 .Fn proc
 731 is called to translate the union.
 732 The end of the
 733 .Vt xdr_discrim
 734 structure array is denoted by a routine of value
 735 .Dv NULL .
 736 If the discriminant is not found in the
 737 .Fa choices
 738 array, then the
 739 .Fn defaultarm
 740 procedure is called (if it is not
 741 .Dv NULL ) .
 742 Returns one if it succeeds, zero otherwise.
 743 .Pp
 744 .It Xo
 745 .Ft int
 746 .Xc
 747 .It Xo
 748 .Fo xdr_vector
 749 .Fa "XDR *xdrs"
 750 .Fa "char *arrp"
 751 .Fa "u_int size"
 752 .Fa "u_int elsize"
 753 .Fa "xdrproc_t elproc"
 754 .Fc
 755 .Xc
 756 .Pp
 757 A filter primitive that translates between fixed-length
 758 arrays
 759 and their corresponding external representations.
 760 The
 761 .Fa arrp
 762 argument
 763 is the address of the pointer to the array, while
 764 .Fa size
 765 is the element count of the array.
 766 The
 767 .Fa elsize
 768 argument
 769 is the
 770 .Ic sizeof
 771 each of the array's elements, and
 772 .Fa elproc
 773 is an
 774 .Tn XDR
 775 filter that translates between
 776 the array elements' C form, and their external
 777 representation.
 778 This routine returns one if it succeeds, zero otherwise.
 779 .Pp
 780 .It Xo
 781 .Ft int
 782 .Xc
 783 .It Xo
 784 .Fn xdr_void void
 785 .Xc
 786 .Pp
 787 This routine always returns one.
 788 It may be passed to
 789 .Tn RPC
 790 routines that require a function argument,
 791 where nothing is to be done.
 792 .Pp
 793 .It Xo
 794 .Ft int
 795 .Xc
 796 .It Xo
 797 .Fn xdr_wrapstring "XDR *xdrs" "char **sp"
 798 .Xc
 799 .Pp
 800 A primitive that calls
 801 .Fn xdr_string xdrs sp MAXUN.UNSIGNED ;
 802 where
 803 .Dv MAXUN.UNSIGNED
 804 is the maximum value of an unsigned integer.
 805 The
 806 .Fn xdr_wrapstring
 807 function
 808 is handy because the
 809 .Tn RPC
 810 package passes a maximum of two
 811 .Tn XDR
 812 routines as arguments, and
 813 .Fn xdr_string ,
 814 one of the most frequently used primitives, requires three.
 815 Returns one if it succeeds, zero otherwise.
 816 .El
 817 .Sh SEE ALSO
 818 .Xr rpc 3
 819 .Rs
 820 .%T "eXternal Data Representation Standard: Protocol Specification"
 821 .Re
 822 .Rs
 823 .%T "eXternal Data Representation: Sun Technical Notes"
 824 .Re
 825 .Rs
 826 .%T "XDR: External Data Representation Standard"
 827 .%O RFC1014
 828 .%Q "Sun Microsystems, Inc., USC\-ISI"
 829 .Re