libguile/__scm.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM___SCM_H
   4 #define SCM___SCM_H
   5
   6 /* Copyright (C) 1995,1996,1998,1999,2000,2001 Free Software Foundation, Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2, or (at your option)
  11  * any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this software; see the file COPYING.  If not, write to
  20  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  21  * Boston, MA 02111-1307 USA
  22  *
  23  * As a special exception, the Free Software Foundation gives permission
  24  * for additional uses of the text contained in its release of GUILE.
  25  *
  26  * The exception is that, if you link the GUILE library with other files
  27  * to produce an executable, this does not by itself cause the
  28  * resulting executable to be covered by the GNU General Public License.
  29  * Your use of that executable is in no way restricted on account of
  30  * linking the GUILE library code into it.
  31  *
  32  * This exception does not however invalidate any other reasons why
  33  * the executable file might be covered by the GNU General Public License.
  34  *
  35  * This exception applies only to the code released by the
  36  * Free Software Foundation under the name GUILE.  If you copy
  37  * code from other Free Software Foundation releases into a copy of
  38  * GUILE, as the General Public License permits, the exception does
  39  * not apply to the code that you add in this way.  To avoid misleading
  40  * anyone as to the status of such modified files, you must delete
  41  * this exception notice from them.
  42  *
  43  * If you write modifications of your own for GUILE, it is your choice
  44  * whether to permit this exception to apply to your modifications.
  45  * If you do not wish that, delete this exception notice.  */
  46
  47 \f
  48
  49 /* "What's the difference between _scm.h and __scm.h?"
  50
  51    _scm.h is not installed; it's only visible to the libguile sources
  52    themselves.
  53
  54    __scm.h is installed, and is #included by <libguile.h>.  If both
  55    the client and libguile need some piece of information, and it
  56    doesn't fit well into the header file for any particular module, it
  57    should go in __scm.h.  */
  58
  59
  60 /* {Compiler hints}
  61  *
  62  * The following macros are used to provide additional information for the
  63  * compiler, which may help to do better error checking and code
  64  * optimization.  A second benefit of these macros is, that they also provide
  65  * additional information to the developers.
  66  */
  67
  68 /* The macro SCM_NORETURN indicates that a function will never return.
  69  * Examples:
  70  *   1) int foo (char arg) SCM_NORETURN;
  71  */
  72 #ifdef __GNUC__
  73 #define SCM_NORETURN __attribute__ ((noreturn))
  74 #else
  75 #define SCM_NORETURN
  76 #endif
  77
  78 /* The macro SCM_UNUSED indicates that a function, function argument or
  79  * variable may potentially be unused.
  80  * Examples:
  81  *   1) static int unused_function (char arg) SCM_UNUSED;
  82  *   2) int foo (char unused_argument SCM_UNUSED);
  83  *   3) int unused_variable SCM_UNUSED;
  84  */
  85 #ifdef __GNUC__
  86 #define SCM_UNUSED __attribute__ ((unused))
  87 #else
  88 #define SCM_UNUSED
  89 #endif
  90
  91
  92 /* {Supported Options}
  93  *
  94  * These may be defined or undefined.
  95  */
  96
  97 /* Old async mechanism */
  98 /* #define GUILE_OLD_ASYNC_CLICK */
  99
 100 /* #define GUILE_DEBUG_FREELIST */
 101
 102 /* If the compile FLAG `SCM_CAUTIOUS' is #defined then the number of
 103  * arguments is always checked for application of closures.  If the
 104  * compile FLAG `SCM_RECKLESS' is #defined then they are not checked.
 105  * Otherwise, number of argument checks for closures are made only
 106  * when the function position (whose value is the closure) of a
 107  * combination is not an ILOC or a variable (true?).  When the
 108  * function position of a combination is a symbol it will be checked
 109  * only the first time it is evaluated because it will then be
 110  * replaced with an ILOC or variable.
 111  */
 112 #undef SCM_RECKLESS
 113 #define SCM_CAUTIOUS
 114
 115 /* After looking up a local for the first time, rewrite the
 116  * code graph, caching its position.
 117  */
 118 #define MEMOIZE_LOCALS
 119
 120 /* All the number support there is.
 121  */
 122 #define BIGNUMS
 123
 124 /* GC should relinquish empty cons-pair arenas. */
 125 /* cmm:FIXME look at this after done mangling the GC */
 126 /* #define GC_FREE_SEGMENTS */
 127
 128 /* Provide a scheme-accessible count-down timer that
 129  * generates a pseudo-interrupt.
 130  */
 131 #define TICKS
 132
 133
 134 /* Use engineering notation when converting numbers strings?
 135  */
 136 #undef ENGNOT
 137
 138 \f
 139 /* {Unsupported Options}
 140  *
 141  * These must be defined as given here.
 142  */
 143
 144
 145 #define CCLO
 146
 147 /* Guile Scheme supports the #f/() distinction; Guile Lisp won't.  We
 148    have horrible plans for their unification.  */
 149 #undef SICP
 150
 151 \f
 152
 153 /* Random options (not yet supported or in final form). */
 154
 155 #define STACK_CHECKING
 156 #undef NO_CEVAL_STACK_CHECKING
 157
 158 \f
 159
 160 /* SCM_API is a macro prepended to all function and data definitions
 161    which should be exported or imported in the resulting dynamic link
 162    library (DLL) in the Win32 port. */
 163
 164 #if defined (SCM_IMPORT)
 165 # define SCM_API __declspec (dllimport) extern
 166 #elif defined (SCM_EXPORT) || defined (DLL_EXPORT)
 167 # define SCM_API __declspec (dllexport) extern
 168 #else
 169 # define SCM_API extern
 170 #endif
 171
 172 \f
 173
 174 /* What did the configure script discover about the outside world?  */
 175 #include "libguile/scmconfig.h"
 176
 177 \f
 178
 179 /* {Debugging Options}
 180  *
 181  * These compile time options determine whether to include code that is only
 182  * useful for debugging guile itself or C level extensions to guile.  The
 183  * common prefix for all option macros of this kind is "SCM_DEBUG_".  It is
 184  * guaranteed that a macro named SCM_DEBUG_XXX is defined to be either 0 or 1,
 185  * i. e. there is no need to test for the undefined case.  This allows to use
 186  * these definitions comfortably within code, as in the following example:
 187  *   #define FOO do { if (SCM_DEBUG_XXX) bar(); else baz(); } while (0)
 188  * Any sane compiler will remove the unused branch without any performance
 189  * penalty for the resulting code.
 190  *
 191  * Note:  Some SCM_DEBUG_XXX options are not settable at configure time.
 192  * To change the value of such options you will have to edit this header
 193  * file or give suitable options to make, like:
 194  *   make all CFLAGS="-DSCM_DEBUG_XXX=1 ..."
 195  */
 196
 197
 198 /* The value of SCM_DEBUG determines the default for most of the not yet
 199  * defined debugging options.  This allows, for example, to enable most of the
 200  * debugging options by simply defining SCM_DEBUG as 1.
 201  */
 202 #ifndef SCM_DEBUG
 203 #define SCM_DEBUG 0
 204 #endif
 205
 206 /* If SCM_DEBUG_CELL_ACCESSES is set to 1, cell accesses will perform
 207  * exhaustive parameter checking:  It will be verified that cell parameters
 208  * actually point to a valid heap cell.  Note:  If this option is enabled,
 209  * guile will run about ten times slower than normally.
 210  */
 211 #ifndef SCM_DEBUG_CELL_ACCESSES
 212 #define SCM_DEBUG_CELL_ACCESSES SCM_DEBUG
 213 #endif
 214
 215 /* If SCM_DEBUG_INTERRUPTS is set to 1, with every deferring and allowing of
 216  * interrupts a consistency check will be performed.
 217  */
 218 #ifndef SCM_DEBUG_INTERRUPTS
 219 #define SCM_DEBUG_INTERRUPTS SCM_DEBUG
 220 #endif
 221
 222 /* If SCM_DEBUG_PAIR_ACCESSES is set to 1, accesses to cons cells will be
 223  * exhaustively checked.  Note:  If this option is enabled, guile will run
 224  * slower than normally.
 225  */
 226 #ifndef SCM_DEBUG_PAIR_ACCESSES
 227 #define SCM_DEBUG_PAIR_ACCESSES SCM_DEBUG
 228 #endif
 229
 230 /* If SCM_DEBUG_REST_ARGUMENT is set to 1, functions that take rest arguments
 231  * will check whether the rest arguments are actually passed as a proper list.
 232  * Otherwise, if SCM_DEBUG_REST_ARGUMENT is 0, functions that take rest
 233  * arguments will take it for granted that these are passed as a proper list.
 234  */
 235 #ifndef SCM_DEBUG_REST_ARGUMENT
 236 #define SCM_DEBUG_REST_ARGUMENT SCM_DEBUG
 237 #endif
 238
 239 /* Use this for _compile time_ type checking only, since the compiled result
 240  * will be quite inefficient.  The right way to make use of this option is to
 241  * do a 'make clean; make CFLAGS=-DSCM_DEBUG_TYPING_STRICTNESS=1', fix your
 242  * errors, and then do 'make clean; make'.
 243  */
 244 #ifndef SCM_DEBUG_TYPING_STRICTNESS
 245 #define SCM_DEBUG_TYPING_STRICTNESS 1
 246 #endif
 247
 248 \f
 249
 250 /* {Feature Options}
 251  *
 252  * These compile time options determine whether code for certain features
 253  * should be compiled into guile.  The common prefix for all option macros
 254  * of this kind is "SCM_ENABLE_".  It is guaranteed that a macro named
 255  * SCM_ENABLE_XXX is defined to be either 0 or 1, i. e. there is no need to
 256  * test for the undefined case.  This allows to use these definitions
 257  * comfortably within code, as in the following example:
 258  *   #define FOO do { if (SCM_ENABLE_XXX) bar(); else baz(); } while (0)
 259  * Any sane compiler will remove the unused branch without any performance
 260  * penalty for the resulting code.
 261  *
 262  * Note:  Some SCM_ENABLE_XXX options are not settable at configure time.
 263  * To change the value of such options you will have to edit this header
 264  * file or give suitable options to make, like:
 265  *   make all CFLAGS="-DSCM_ENABLE_XXX=1 ..."
 266  */
 267
 268 /* If SCM_ENABLE_DEPRECATED is set to 1, deprecated code will be included in
 269  * guile, as well as some functions to issue run-time warnings about uses of
 270  * deprecated functions.
 271  */
 272 #ifndef SCM_ENABLE_DEPRECATED
 273 #define SCM_ENABLE_DEPRECATED 0
 274 #endif
 275
 276 \f
 277
 278 /* {Architecture and compiler properties}
 279  *
 280  * Guile as of today can only work on systems which fulfill at least the
 281  * following requirements:
 282  * - long ints have at least 32 bits.
 283  *   Guile's type system is based on this assumption.
 284  * - long ints consist of at least four characters.
 285  *   It is assumed that cells, i. e. pairs of long ints, are eight character
 286  *   aligned, because three bits of a cell pointer are used for type data.
 287  * - sizeof (void*) == sizeof (long int)
 288  *   Pointers are stored in SCM objects, and sometimes SCM objects are passed
 289  *   as void*.  Thus, there has to be a one-to-one correspondence.
 290  * - numbers are encoded using two's complement.
 291  *   The implementation of the bitwise scheme level operations is based on
 292  *   this assumption.
 293  * - ... add more
 294  */
 295
 296 #if SIZEOF_UINTPTR_T != 0
 297 #define HAVE_UINTPTR_T
 298 #endif
 299
 300 #if SIZEOF_PTRDIFF_T != 0
 301 #define HAVE_PTRDIFF_T
 302 #endif
 303
 304 #if SIZEOF_LONG_LONG != 0
 305 #define HAVE_LONG_LONGS
 306 #define HAVE_LONG_LONG
 307 #endif
 308
 309 #ifndef HAVE_PTRDIFF_T
 310 typedef long ptrdiff_t;
 311 #endif
 312
 313 #ifdef HAVE_LIMITS_H
 314 # include <limits.h>
 315 #endif
 316
 317 #ifdef CHAR_BIT
 318 # define SCM_CHAR_BIT CHAR_BIT
 319 #else
 320 # define SCM_CHAR_BIT 8
 321 #endif
 322
 323 #ifdef LONG_BIT
 324 # define SCM_LONG_BIT LONG_BIT
 325 #else
 326 # define SCM_LONG_BIT (SCM_CHAR_BIT * sizeof (long) / sizeof (char))
 327 #endif
 328
 329 #ifdef UCHAR_MAX
 330 # define SCM_CHAR_CODE_LIMIT (UCHAR_MAX + 1L)
 331 #else
 332 # define SCM_CHAR_CODE_LIMIT 256L
 333 #endif
 334
 335 \f
 336
 337 #ifdef STDC_HEADERS
 338 # include <stdlib.h>
 339 # if HAVE_SYS_TYPES_H
 340 #  include <sys/types.h>
 341 # endif
 342 # if HAVE_SYS_STDTYPES_H
 343 #  include <sys/stdtypes.h>
 344 # endif
 345 #  include <stddef.h>
 346 #endif /* def STDC_HEADERS */
 347
 348 \f
 349
 350 /* Define some additional CPP macros on Win32 platforms. */
 351 #if USE_DLL_IMPORT
 352 # define __REGEX_IMPORT__ 1
 353 # define __CRYPT_IMPORT__ 1
 354 # define __READLINE_IMPORT__ 1
 355 # define QT_IMPORT 1
 356 #endif
 357
 358 \f
 359
 360 #include "libguile/tags.h"
 361
 362 \f
 363 #ifdef vms
 364 # ifndef CHEAP_CONTINUATIONS
 365    typedef int jmp_buf[17];
 366    extern int setjump(jmp_buf env);
 367    extern int longjump(jmp_buf env, int ret);
 368 #  define setjmp setjump
 369 #  define longjmp longjump
 370 # else
 371 #  include <setjmp.h>
 372 # endif
 373 #else                           /* ndef vms */
 374 # ifdef _CRAY1
 375     typedef int jmp_buf[112];
 376     extern int setjump(jmp_buf env);
 377     extern int longjump(jmp_buf env, int ret);
 378 #  define setjmp setjump
 379 #  define longjmp longjump
 380 # else                          /* ndef _CRAY1 */
 381 #  include <setjmp.h>
 382 # endif                         /* ndef _CRAY1 */
 383 #endif                          /* ndef vms */
 384
 385 /* James Clark came up with this neat one instruction fix for
 386  * continuations on the SPARC.  It flushes the register windows so
 387  * that all the state of the process is contained in the stack.
 388  */
 389
 390 #ifdef sparc
 391 # define SCM_FLUSH_REGISTER_WINDOWS asm("ta 3")
 392 #else
 393 # define SCM_FLUSH_REGISTER_WINDOWS /* empty */
 394 #endif
 395
 396 /* If stack is not longword aligned then
 397  */
 398
 399 /* #define SHORT_ALIGN */
 400 #ifdef THINK_C
 401 # define SHORT_ALIGN
 402 #endif
 403 #ifdef MSDOS
 404 # define SHORT_ALIGN
 405 #endif
 406 #ifdef atarist
 407 # define SHORT_ALIGN
 408 #endif
 409
 410 #ifdef SHORT_ALIGN
 411 typedef short SCM_STACKITEM;
 412 #else
 413 typedef long SCM_STACKITEM;
 414 #endif
 415 \f
 416
 417 #ifndef USE_THREADS
 418 #define SCM_CRITICAL_SECTION_START
 419 #define SCM_CRITICAL_SECTION_END
 420 #define SCM_THREAD_SWITCHING_CODE
 421 #endif
 422
 423 #ifdef GUILE_OLD_ASYNC_CLICK
 424 SCM_API unsigned int scm_async_clock;
 425
 426 #define SCM_ASYNC_TICK \
 427 do { \
 428   if (0 == --scm_async_clock) \
 429     scm_async_click (); \
 430 } while(0)
 431 #else
 432 SCM_API int scm_asyncs_pending_p;
 433
 434 #define SCM_ASYNC_TICK /*fixme* should change names */ \
 435 do { \
 436   if (scm_asyncs_pending_p) \
 437     scm_async_click (); \
 438 } while (0)
 439 #endif
 440
 441 #if (SCM_DEBUG_INTERRUPTS == 1)
 442 #include <stdio.h>
 443 #define SCM_CHECK_NOT_DISABLED \
 444   do { \
 445     if (scm_ints_disabled) \
 446       fprintf(stderr, "ints already disabled (at %s:%d)\n", \
 447               __FILE__, __LINE__); \
 448   } while (0)
 449
 450 #define SCM_CHECK_NOT_ENABLED \
 451   do { \
 452     if (!scm_ints_disabled) \
 453       fprintf(stderr, "ints already enabled (at %s:%d)\n", \
 454               __FILE__, __LINE__); \
 455   } while (0)
 456
 457 #else
 458 #define SCM_CHECK_NOT_DISABLED
 459 #define SCM_CHECK_NOT_ENABLED
 460 #endif
 461
 462
 463 /* Anthony Green writes:
 464    When the compiler sees...
 465            DEFER_INTS;
 466            [critical code here]
 467            ALLOW_INTS;
 468    ...it doesn't actually promise to keep the critical code within the
 469    boundries of the DEFER/ALLOW_INTS instructions. It may very well
 470    schedule it outside of the magic defined in those macros.
 471
 472    However, GCC's volatile asm feature forms a barrier over which code is
 473    never moved. So if you add...
 474            asm ("");
 475    ...to each of the DEFER_INTS and ALLOW_INTS macros, the critical
 476    code will always remain in place.  asm's without inputs or outputs
 477    are implicitly volatile. */
 478 #ifdef __GNUC__
 479 #define SCM_FENCE asm /* volatile */ ("")
 480 #else
 481 #define SCM_FENCE
 482 #endif
 483
 484 #define SCM_DEFER_INTS \
 485 do { \
 486   SCM_FENCE; \
 487   SCM_CHECK_NOT_DISABLED; \
 488   SCM_CRITICAL_SECTION_START; \
 489   SCM_FENCE; \
 490   scm_ints_disabled = 1; \
 491   SCM_FENCE; \
 492 } while (0)
 493
 494
 495 #define SCM_ALLOW_INTS_ONLY \
 496 do { \
 497   SCM_CRITICAL_SECTION_END; \
 498   scm_ints_disabled = 0; \
 499 } while (0)
 500
 501
 502 #define SCM_ALLOW_INTS \
 503 do { \
 504   SCM_FENCE; \
 505   SCM_CHECK_NOT_ENABLED; \
 506   SCM_CRITICAL_SECTION_END; \
 507   SCM_FENCE; \
 508   scm_ints_disabled = 0; \
 509   SCM_FENCE; \
 510   SCM_THREAD_SWITCHING_CODE; \
 511   SCM_FENCE; \
 512 } while (0)
 513
 514
 515 #define SCM_REDEFER_INTS  \
 516 do { \
 517   SCM_FENCE; \
 518   SCM_CRITICAL_SECTION_START; \
 519   ++scm_ints_disabled; \
 520   SCM_FENCE; \
 521 } while (0)
 522
 523
 524 #define SCM_REALLOW_INTS \
 525 do { \
 526   SCM_FENCE; \
 527   SCM_CRITICAL_SECTION_END; \
 528   SCM_FENCE; \
 529   --scm_ints_disabled; \
 530   SCM_FENCE; \
 531 } while (0)
 532
 533
 534 #define SCM_TICK \
 535 do { \
 536   SCM_ASYNC_TICK; \
 537   SCM_THREAD_SWITCHING_CODE; \
 538 } while (0)
 539
 540 \f
 541
 542 /* Classification of critical sections
 543  *
 544  * When Guile moves to POSIX threads, it won't be possible to prevent
 545  * context switching.  In fact, the whole idea of context switching is
 546  * bogus if threads are run by different processors.  Therefore, we
 547  * must ultimately eliminate all critical sections or enforce them by
 548  * use of mutecis.
 549  *
 550  * All instances of SCM_DEFER_INTS and SCM_ALLOW_INTS should therefore
 551  * be classified and replaced by one of the delimiters below.  If you
 552  * understand what this is all about, I'd like to encourage you to
 553  * help with this task.  The set of classes below must of course be
 554  * incrementally augmented.
 555  *
 556  * MDJ 980419 <djurfeldt@nada.kth.se>
 557  */
 558
 559 /* A sections
 560  *
 561  * Allocation of a cell with type tag in the CAR.
 562  *
 563  * With POSIX threads, each thread will have a private pool of free
 564  * cells.  Therefore, this type of section can be removed.  But!  It
 565  * is important that the CDR is initialized first (with the CAR still
 566  * indicating a free cell) so that we can guarantee a consistent heap
 567  * at all times.
 568  */
 569
 570 #define SCM_ENTER_A_SECTION SCM_CRITICAL_SECTION_START
 571 #define SCM_EXIT_A_SECTION SCM_CRITICAL_SECTION_END
 572
 573 \f
 574
 575 /** SCM_ASSERT
 576  **
 577  **/
 578
 579
 580 #ifdef SCM_RECKLESS
 581 #define SCM_ASSERT(_cond, _arg, _pos, _subr)
 582 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg)
 583 #define SCM_ASRTGO(_cond, _label)
 584 #else
 585 #define SCM_ASSERT(_cond, _arg, _pos, _subr) \
 586         if (!(_cond)) \
 587           scm_wrong_type_arg (_subr, _pos, _arg)
 588 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg) \
 589         if (!(_cond)) \
 590           scm_wrong_type_arg_msg(_subr, _pos, _arg, _msg)
 591 #define SCM_ASRTGO(_cond, _label) \
 592         if (!(_cond)) \
 593           goto _label
 594 #endif
 595
 596 /*
 597  * SCM_WTA_DISPATCH
 598  */
 599
 600 /* Dirk:FIXME:: In all of the SCM_WTA_DISPATCH_* macros it is assumed that
 601  * 'gf' is zero if uninitialized.  It would be cleaner if some valid SCM value
 602  * like SCM_BOOL_F or SCM_UNDEFINED was chosen.
 603  */
 604
 605 SCM_API SCM scm_call_generic_0 (SCM gf);
 606
 607 #define SCM_WTA_DISPATCH_0(gf, subr)                            \
 608   return (SCM_UNPACK (gf)                                       \
 609           ? scm_call_generic_0 ((gf))                           \
 610           : (scm_error_num_args_subr ((subr)), SCM_UNSPECIFIED))
 611 #define SCM_GASSERT0(cond, gf, subr) \
 612   if (!(cond)) SCM_WTA_DISPATCH_0((gf), (subr))
 613
 614 SCM_API SCM scm_call_generic_1 (SCM gf, SCM a1);
 615
 616 #define SCM_WTA_DISPATCH_1(gf, a1, pos, subr)                   \
 617   return (SCM_UNPACK (gf)                                       \
 618           ? scm_call_generic_1 ((gf), (a1))                     \
 619           : (scm_wrong_type_arg ((subr), (pos), (a1)), SCM_UNSPECIFIED))
 620 #define SCM_GASSERT1(cond, gf, a1, pos, subr) \
 621   if (!(cond)) SCM_WTA_DISPATCH_1((gf), (a1), (pos), (subr))
 622
 623 SCM_API SCM scm_call_generic_2 (SCM gf, SCM a1, SCM a2);
 624
 625 #define SCM_WTA_DISPATCH_2(gf, a1, a2, pos, subr)                       \
 626   return (SCM_UNPACK (gf)                                               \
 627           ? scm_call_generic_2 ((gf), (a1), (a2))                       \
 628           : (scm_wrong_type_arg ((subr), (pos),                         \
 629                                  (pos) == SCM_ARG1 ? (a1) : (a2)),      \
 630              SCM_UNSPECIFIED))
 631 #define SCM_GASSERT2(cond, gf, a1, a2, pos, subr) \
 632   if (!(cond)) SCM_WTA_DISPATCH_2((gf), (a1), (a2), (pos), (subr))
 633
 634 SCM_API SCM scm_apply_generic (SCM gf, SCM args);
 635
 636 #define SCM_WTA_DISPATCH_n(gf, args, pos, subr)                           \
 637   return (SCM_UNPACK (gf)                                                 \
 638           ? scm_apply_generic ((gf), (args))                              \
 639           : (scm_wrong_type_arg ((subr), (pos),                           \
 640                                  scm_list_ref ((args),                    \
 641                                                SCM_MAKINUM ((pos) - 1))), \
 642              SCM_UNSPECIFIED))
 643 #define SCM_GASSERTn(cond, gf, args, pos, subr) \
 644   if (!(cond)) SCM_WTA_DISPATCH_n((gf), (args), (pos), (subr))
 645
 646 #ifndef SCM_MAGIC_SNARFER
 647 /* Let these macros pass through if
 648    we are snarfing;  thus we can tell the
 649    difference between the use of an actual
 650    number vs. the use of one of these macros --
 651    actual numbers in SCM_VALIDATE_* and SCM_ASSERT
 652    constructs must match the formal argument name,
 653    but using SCM_ARG* avoids the test */
 654
 655 #define SCM_ARGn                0
 656 #define SCM_ARG1                1
 657 #define SCM_ARG2                2
 658 #define SCM_ARG3                3
 659 #define SCM_ARG4                4
 660 #define SCM_ARG5                5
 661 #define SCM_ARG6                6
 662 #define SCM_ARG7                7
 663
 664 #endif /* SCM_MAGIC_SNARFER */
 665
 666 \f
 667
 668 /* SCM_EXIT_SUCCESS is the default code to return from SCM if no errors
 669  * were encountered.  SCM_EXIT_FAILURE is the default code to return from
 670  * SCM if errors were encountered.  The return code can be explicitly
 671  * specified in a SCM program with (scm_quit <n>).
 672  */
 673
 674 #ifndef SCM_EXIT_SUCCESS
 675 #ifdef vms
 676 #define SCM_EXIT_SUCCESS 1
 677 #else
 678 #define SCM_EXIT_SUCCESS 0
 679 #endif /* def vms */
 680 #endif /* ndef SCM_EXIT_SUCCESS */
 681 #ifndef SCM_EXIT_FAILURE
 682 #ifdef vms
 683 #define SCM_EXIT_FAILURE 2
 684 #else
 685 #define SCM_EXIT_FAILURE 1
 686 #endif /* def vms */
 687 #endif /* ndef SCM_EXIT_FAILURE */
 688
 689 #endif  /* SCM___SCM_H */
 690
 691 /*
 692   Local Variables:
 693   c-file-style: "gnu"
 694   End:
 695 */