libguile/__scm.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM___SCM_H
   4 #define SCM___SCM_H
   5
   6 /* Copyright (C) 1995,1996,1998,1999,2000,2001,2002 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 /**********************************************************************
  50  This file is Guile's central public header.
  51
  52  When included by other files, this file should preceed any include
  53  other than __scm.h.
  54
  55  Under *NO* circumstances should new items be added to the global
  56  namespace (via adding #define, typedef, or similar to this file) with
  57  generic names.  This usually means that any new names should be
  58  prefixed by either SCM_ or GUILE_.  i.e. do *not* #define HAVE_FOO or
  59  SIZEOF_BAR.  See configure.in, gen-scmconfig.h.in, and
  60  gen-scmconfig.c for examples of how to properly handle this issue.
  61  The main documentation is in gen-scmconfig.c.
  62
  63  "What's the difference between _scm.h and __scm.h?"
  64
  65    _scm.h is not installed; it's only visible to the libguile sources
  66    themselves, and it includes config.h, the private config header.
  67
  68    __scm.h is installed, and is #included by <libguile.h>.  If both
  69    the client and libguile need some piece of information, and it
  70    doesn't fit well into the header file for any particular module, it
  71    should go in __scm.h.  __scm.h includes scmconfig.h, the public
  72    config header.
  73  **********************************************************************/
  74
  75 /* What did the configure script discover about the outside world?  */
  76 #include "libguile/scmconfig.h"
  77
  78 \f
  79
  80 /* {Compiler hints}
  81  *
  82  * The following macros are used to provide additional information for the
  83  * compiler, which may help to do better error checking and code
  84  * optimization.  A second benefit of these macros is, that they also provide
  85  * additional information to the developers.
  86  */
  87
  88 /* The macro SCM_NORETURN indicates that a function will never return.
  89  * Examples:
  90  *   1) int foo (char arg) SCM_NORETURN;
  91  */
  92 #ifdef __GNUC__
  93 #define SCM_NORETURN __attribute__ ((noreturn))
  94 #else
  95 #define SCM_NORETURN
  96 #endif
  97
  98 /* The macro SCM_UNUSED indicates that a function, function argument or
  99  * variable may potentially be unused.
 100  * Examples:
 101  *   1) static int unused_function (char arg) SCM_UNUSED;
 102  *   2) int foo (char unused_argument SCM_UNUSED);
 103  *   3) int unused_variable SCM_UNUSED;
 104  */
 105 #ifdef __GNUC__
 106 #define SCM_UNUSED __attribute__ ((unused))
 107 #else
 108 #define SCM_UNUSED
 109 #endif
 110
 111
 112 /* {Supported Options}
 113  *
 114  * These may be defined or undefined.
 115  */
 116
 117 /* #define GUILE_DEBUG_FREELIST */
 118
 119 /* All the number support there is.
 120  */
 121 #define BIGNUMS
 122
 123 /* GC should relinquish empty cons-pair arenas. */
 124 /* cmm:FIXME look at this after done mangling the GC */
 125 /* #define GC_FREE_SEGMENTS */
 126
 127 /* Provide a scheme-accessible count-down timer that
 128  * generates a pseudo-interrupt.
 129  */
 130 #define TICKS
 131
 132
 133 /* Use engineering notation when converting numbers strings?
 134  */
 135 #undef ENGNOT
 136
 137 \f
 138 /* {Unsupported Options}
 139  *
 140  * These must be defined as given here.
 141  */
 142
 143
 144 #define CCLO
 145
 146 /* Guile Scheme supports the #f/() distinction; Guile Lisp won't.  We
 147    have horrible plans for their unification.  */
 148 #undef SICP
 149
 150 \f
 151
 152 /* Random options (not yet supported or in final form). */
 153
 154 #define STACK_CHECKING
 155 #undef NO_CEVAL_STACK_CHECKING
 156
 157 \f
 158
 159 /* SCM_API is a macro prepended to all function and data definitions
 160    which should be exported or imported in the resulting dynamic link
 161    library (DLL) in the Win32 port. */
 162
 163 #if defined (SCM_IMPORT)
 164 # define SCM_API __declspec (dllimport) extern
 165 #elif defined (SCM_EXPORT) || defined (DLL_EXPORT)
 166 # define SCM_API __declspec (dllexport) extern
 167 #else
 168 # define SCM_API extern
 169 #endif
 170
 171 \f
 172
 173 /* {Debugging Options}
 174  *
 175  * These compile time options determine whether to include code that is only
 176  * useful for debugging guile itself or C level extensions to guile.  The
 177  * common prefix for all option macros of this kind is "SCM_DEBUG_".  It is
 178  * guaranteed that a macro named SCM_DEBUG_XXX is defined to be either 0 or 1,
 179  * i. e. there is no need to test for the undefined case.  This allows to use
 180  * these definitions comfortably within code, as in the following example:
 181  *   #define FOO do { if (SCM_DEBUG_XXX) bar(); else baz(); } while (0)
 182  * Any sane compiler will remove the unused branch without any performance
 183  * penalty for the resulting code.
 184  *
 185  * Note:  Some SCM_DEBUG_XXX options are not settable at configure time.
 186  * To change the value of such options you will have to edit this header
 187  * file or give suitable options to make, like:
 188  *   make all CFLAGS="-DSCM_DEBUG_XXX=1 ..."
 189  */
 190
 191
 192 /* The value of SCM_DEBUG determines the default for most of the not yet
 193  * defined debugging options.  This allows, for example, to enable most of the
 194  * debugging options by simply defining SCM_DEBUG as 1.
 195  */
 196 #ifndef SCM_DEBUG
 197 #define SCM_DEBUG 0
 198 #endif
 199
 200 /* If SCM_DEBUG_CELL_ACCESSES is set to 1, cell accesses will perform
 201  * exhaustive parameter checking:  It will be verified that cell parameters
 202  * actually point to a valid heap cell.  Note:  If this option is enabled,
 203  * guile will run about ten times slower than normally.
 204  */
 205 #ifndef SCM_DEBUG_CELL_ACCESSES
 206 #define SCM_DEBUG_CELL_ACCESSES SCM_DEBUG
 207 #endif
 208
 209 /* If SCM_DEBUG_INTERRUPTS is set to 1, with every deferring and allowing of
 210  * interrupts a consistency check will be performed.
 211  */
 212 #ifndef SCM_DEBUG_INTERRUPTS
 213 #define SCM_DEBUG_INTERRUPTS SCM_DEBUG
 214 #endif
 215
 216 /* If SCM_DEBUG_PAIR_ACCESSES is set to 1, accesses to cons cells will be
 217  * exhaustively checked.  Note:  If this option is enabled, guile will run
 218  * slower than normally.
 219  */
 220 #ifndef SCM_DEBUG_PAIR_ACCESSES
 221 #define SCM_DEBUG_PAIR_ACCESSES SCM_DEBUG
 222 #endif
 223
 224 /* If SCM_DEBUG_REST_ARGUMENT is set to 1, functions that take rest arguments
 225  * will check whether the rest arguments are actually passed as a proper list.
 226  * Otherwise, if SCM_DEBUG_REST_ARGUMENT is 0, functions that take rest
 227  * arguments will take it for granted that these are passed as a proper list.
 228  */
 229 #ifndef SCM_DEBUG_REST_ARGUMENT
 230 #define SCM_DEBUG_REST_ARGUMENT SCM_DEBUG
 231 #endif
 232
 233 /* Use this for _compile time_ type checking only, since the compiled result
 234  * will be quite inefficient.  The right way to make use of this option is to
 235  * do a 'make clean; make CFLAGS=-DSCM_DEBUG_TYPING_STRICTNESS=1', fix your
 236  * errors, and then do 'make clean; make'.
 237  */
 238 #ifndef SCM_DEBUG_TYPING_STRICTNESS
 239 #define SCM_DEBUG_TYPING_STRICTNESS 1
 240 #endif
 241
 242 \f
 243
 244 /* {Feature Options}
 245  *
 246  * These compile time options determine whether code for certain features
 247  * should be compiled into guile.  The common prefix for all option macros
 248  * of this kind is "SCM_ENABLE_".  It is guaranteed that a macro named
 249  * SCM_ENABLE_XXX is defined to be either 0 or 1, i. e. there is no need to
 250  * test for the undefined case.  This allows to use these definitions
 251  * comfortably within code, as in the following example:
 252  *   #define FOO do { if (SCM_ENABLE_XXX) bar(); else baz(); } while (0)
 253  * Any sane compiler will remove the unused branch without any performance
 254  * penalty for the resulting code.
 255  *
 256  * Note:  Some SCM_ENABLE_XXX options are not settable at configure time.
 257  * To change the value of such options you will have to edit this header
 258  * file or give suitable options to make, like:
 259  *   make all CFLAGS="-DSCM_ENABLE_XXX=1 ..."
 260  */
 261
 262 /* If SCM_ENABLE_DEPRECATED is set to 1, deprecated code will be included in
 263  * guile, as well as some functions to issue run-time warnings about uses of
 264  * deprecated functions.
 265  */
 266 #ifndef SCM_ENABLE_DEPRECATED
 267 #define SCM_ENABLE_DEPRECATED 0
 268 #endif
 269
 270 \f
 271
 272 /* {Architecture and compiler properties}
 273  *
 274  * Guile as of today can only work on systems which fulfill at least the
 275  * following requirements:
 276  * - long ints have at least 32 bits.
 277  *   Guile's type system is based on this assumption.
 278  * - long ints consist of at least four characters.
 279  *   It is assumed that cells, i. e. pairs of long ints, are eight character
 280  *   aligned, because three bits of a cell pointer are used for type data.
 281  * - sizeof (void*) == sizeof (long int)
 282  *   Pointers are stored in SCM objects, and sometimes SCM objects are passed
 283  *   as void*.  Thus, there has to be a one-to-one correspondence.
 284  * - numbers are encoded using two's complement.
 285  *   The implementation of the bitwise scheme level operations is based on
 286  *   this assumption.
 287  * - ... add more
 288  */
 289
 290 #ifdef CHAR_BIT
 291 # define SCM_CHAR_BIT CHAR_BIT
 292 #else
 293 # define SCM_CHAR_BIT 8
 294 #endif
 295
 296 #ifdef LONG_BIT
 297 # define SCM_LONG_BIT LONG_BIT
 298 #else
 299 # define SCM_LONG_BIT (SCM_CHAR_BIT * sizeof (long) / sizeof (char))
 300 #endif
 301
 302 #ifdef UCHAR_MAX
 303 # define SCM_CHAR_CODE_LIMIT (UCHAR_MAX + 1L)
 304 #else
 305 # define SCM_CHAR_CODE_LIMIT 256L
 306 #endif
 307
 308 \f
 309
 310 #include "libguile/tags.h"
 311
 312 \f
 313 #ifdef vms
 314 # ifndef CHEAP_CONTINUATIONS
 315    typedef int jmp_buf[17];
 316    extern int setjump(jmp_buf env);
 317    extern int longjump(jmp_buf env, int ret);
 318 #  define setjmp setjump
 319 #  define longjmp longjump
 320 # else
 321 #  include <setjmp.h>
 322 # endif
 323 #else                           /* ndef vms */
 324 # ifdef _CRAY1
 325     typedef int jmp_buf[112];
 326     extern int setjump(jmp_buf env);
 327     extern int longjump(jmp_buf env, int ret);
 328 #  define setjmp setjump
 329 #  define longjmp longjump
 330 # else                          /* ndef _CRAY1 */
 331 #  include <setjmp.h>
 332 # endif                         /* ndef _CRAY1 */
 333 #endif                          /* ndef vms */
 334
 335 /* James Clark came up with this neat one instruction fix for
 336  * continuations on the SPARC.  It flushes the register windows so
 337  * that all the state of the process is contained in the stack.
 338  */
 339
 340 #if defined (sparc) || defined (__sparc__) || defined (__sparc)
 341 # define SCM_FLUSH_REGISTER_WINDOWS asm("ta 3")
 342 #else
 343 # define SCM_FLUSH_REGISTER_WINDOWS /* empty */
 344 #endif
 345
 346 /* If stack is not longword aligned then
 347  */
 348
 349 /* #define SHORT_ALIGN */
 350 #ifdef THINK_C
 351 # define SHORT_ALIGN
 352 #endif
 353 #ifdef MSDOS
 354 # define SHORT_ALIGN
 355 #endif
 356 #ifdef atarist
 357 # define SHORT_ALIGN
 358 #endif
 359
 360 #ifdef SHORT_ALIGN
 361 typedef short SCM_STACKITEM;
 362 #else
 363 typedef long SCM_STACKITEM;
 364 #endif
 365 \f
 366
 367 #define SCM_ASYNC_TICK /*fixme* should change names */ \
 368 do { \
 369   if (scm_root->pending_asyncs) \
 370     scm_async_click (); \
 371 } while (0)
 372
 373
 374 /* Anthony Green writes:
 375    When the compiler sees...
 376            DEFER_INTS;
 377            [critical code here]
 378            ALLOW_INTS;
 379    ...it doesn't actually promise to keep the critical code within the
 380    boundries of the DEFER/ALLOW_INTS instructions. It may very well
 381    schedule it outside of the magic defined in those macros.
 382
 383    However, GCC's volatile asm feature forms a barrier over which code is
 384    never moved. So if you add...
 385            asm ("");
 386    ...to each of the DEFER_INTS and ALLOW_INTS macros, the critical
 387    code will always remain in place.  asm's without inputs or outputs
 388    are implicitly volatile. */
 389 #ifdef __GNUC__
 390 #define SCM_FENCE asm /* volatile */ ("")
 391 #else
 392 #define SCM_FENCE
 393 #endif
 394
 395 #define SCM_DEFER_INTS scm_rec_mutex_lock (&scm_i_defer_mutex);
 396
 397 #define SCM_ALLOW_INTS scm_rec_mutex_unlock (&scm_i_defer_mutex);
 398
 399 #define SCM_REDEFER_INTS SCM_DEFER_INTS
 400
 401 #define SCM_REALLOW_INTS SCM_ALLOW_INTS
 402
 403 #define SCM_TICK \
 404 do { \
 405   SCM_ASYNC_TICK; \
 406   SCM_THREAD_SWITCHING_CODE; \
 407 } while (0)
 408
 409 \f
 410
 411 /* Note: The following needs updating. */
 412
 413 /* Classification of critical sections
 414  *
 415  * When Guile moves to POSIX threads, it won't be possible to prevent
 416  * context switching.  In fact, the whole idea of context switching is
 417  * bogus if threads are run by different processors.  Therefore, we
 418  * must ultimately eliminate all critical sections or enforce them by
 419  * use of mutecis.
 420  *
 421  * All instances of SCM_DEFER_INTS and SCM_ALLOW_INTS should therefore
 422  * be classified and replaced by one of the delimiters below.  If you
 423  * understand what this is all about, I'd like to encourage you to
 424  * help with this task.  The set of classes below must of course be
 425  * incrementally augmented.
 426  *
 427  * MDJ 980419 <djurfeldt@nada.kth.se>
 428  */
 429
 430 /* A sections
 431  *
 432  * Allocation of a cell with type tag in the CAR.
 433  *
 434  * With POSIX threads, each thread will have a private pool of free
 435  * cells.  Therefore, this type of section can be removed.  But!  It
 436  * is important that the CDR is initialized first (with the CAR still
 437  * indicating a free cell) so that we can guarantee a consistent heap
 438  * at all times.
 439  */
 440
 441 #define SCM_ENTER_A_SECTION SCM_CRITICAL_SECTION_START
 442 #define SCM_EXIT_A_SECTION SCM_CRITICAL_SECTION_END
 443
 444 \f
 445
 446 /** SCM_ASSERT
 447  **
 448  **/
 449
 450
 451 #ifdef SCM_RECKLESS
 452 #define SCM_ASSERT(_cond, _arg, _pos, _subr)
 453 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg)
 454 #define SCM_ASRTGO(_cond, _label)
 455 #else
 456 #define SCM_ASSERT(_cond, _arg, _pos, _subr) \
 457         if (!(_cond)) \
 458           scm_wrong_type_arg (_subr, _pos, _arg)
 459 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg) \
 460         if (!(_cond)) \
 461           scm_wrong_type_arg_msg(_subr, _pos, _arg, _msg)
 462 #define SCM_ASRTGO(_cond, _label) \
 463         if (!(_cond)) \
 464           goto _label
 465 #endif
 466
 467 /*
 468  * SCM_WTA_DISPATCH
 469  */
 470
 471 /* Dirk:FIXME:: In all of the SCM_WTA_DISPATCH_* macros it is assumed that
 472  * 'gf' is zero if uninitialized.  It would be cleaner if some valid SCM value
 473  * like SCM_BOOL_F or SCM_UNDEFINED was chosen.
 474  */
 475
 476 SCM_API SCM scm_call_generic_0 (SCM gf);
 477
 478 #define SCM_WTA_DISPATCH_0(gf, subr)                            \
 479   return (SCM_UNPACK (gf)                                       \
 480           ? scm_call_generic_0 ((gf))                           \
 481           : (scm_error_num_args_subr ((subr)), SCM_UNSPECIFIED))
 482 #define SCM_GASSERT0(cond, gf, subr) \
 483   if (!(cond)) SCM_WTA_DISPATCH_0((gf), (subr))
 484
 485 SCM_API SCM scm_call_generic_1 (SCM gf, SCM a1);
 486
 487 #define SCM_WTA_DISPATCH_1(gf, a1, pos, subr)                   \
 488   return (SCM_UNPACK (gf)                                       \
 489           ? scm_call_generic_1 ((gf), (a1))                     \
 490           : (scm_wrong_type_arg ((subr), (pos), (a1)), SCM_UNSPECIFIED))
 491 #define SCM_GASSERT1(cond, gf, a1, pos, subr) \
 492   if (!(cond)) SCM_WTA_DISPATCH_1((gf), (a1), (pos), (subr))
 493
 494 SCM_API SCM scm_call_generic_2 (SCM gf, SCM a1, SCM a2);
 495
 496 #define SCM_WTA_DISPATCH_2(gf, a1, a2, pos, subr)                       \
 497   return (SCM_UNPACK (gf)                                               \
 498           ? scm_call_generic_2 ((gf), (a1), (a2))                       \
 499           : (scm_wrong_type_arg ((subr), (pos),                         \
 500                                  (pos) == SCM_ARG1 ? (a1) : (a2)),      \
 501              SCM_UNSPECIFIED))
 502 #define SCM_GASSERT2(cond, gf, a1, a2, pos, subr) \
 503   if (!(cond)) SCM_WTA_DISPATCH_2((gf), (a1), (a2), (pos), (subr))
 504
 505 SCM_API SCM scm_apply_generic (SCM gf, SCM args);
 506
 507 #define SCM_WTA_DISPATCH_n(gf, args, pos, subr)                           \
 508   return (SCM_UNPACK (gf)                                                 \
 509           ? scm_apply_generic ((gf), (args))                              \
 510           : (scm_wrong_type_arg ((subr), (pos),                           \
 511                                  scm_list_ref ((args),                    \
 512                                                SCM_MAKINUM ((pos) - 1))), \
 513              SCM_UNSPECIFIED))
 514 #define SCM_GASSERTn(cond, gf, args, pos, subr) \
 515   if (!(cond)) SCM_WTA_DISPATCH_n((gf), (args), (pos), (subr))
 516
 517 #ifndef SCM_MAGIC_SNARFER
 518 /* Let these macros pass through if
 519    we are snarfing;  thus we can tell the
 520    difference between the use of an actual
 521    number vs. the use of one of these macros --
 522    actual numbers in SCM_VALIDATE_* and SCM_ASSERT
 523    constructs must match the formal argument name,
 524    but using SCM_ARG* avoids the test */
 525
 526 #define SCM_ARGn                0
 527 #define SCM_ARG1                1
 528 #define SCM_ARG2                2
 529 #define SCM_ARG3                3
 530 #define SCM_ARG4                4
 531 #define SCM_ARG5                5
 532 #define SCM_ARG6                6
 533 #define SCM_ARG7                7
 534
 535 #endif /* SCM_MAGIC_SNARFER */
 536
 537 \f
 538
 539 /* SCM_EXIT_SUCCESS is the default code to return from SCM if no errors
 540  * were encountered.  SCM_EXIT_FAILURE is the default code to return from
 541  * SCM if errors were encountered.  The return code can be explicitly
 542  * specified in a SCM program with (scm_quit <n>).
 543  */
 544
 545 #ifndef SCM_EXIT_SUCCESS
 546 #ifdef vms
 547 #define SCM_EXIT_SUCCESS 1
 548 #else
 549 #define SCM_EXIT_SUCCESS 0
 550 #endif /* def vms */
 551 #endif /* ndef SCM_EXIT_SUCCESS */
 552 #ifndef SCM_EXIT_FAILURE
 553 #ifdef vms
 554 #define SCM_EXIT_FAILURE 2
 555 #else
 556 #define SCM_EXIT_FAILURE 1
 557 #endif /* def vms */
 558 #endif /* ndef SCM_EXIT_FAILURE */
 559
 560 #endif  /* SCM___SCM_H */
 561
 562 /*
 563   Local Variables:
 564   c-file-style: "gnu"
 565   End:
 566 */