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 /* "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 /* #define GUILE_DEBUG_FREELIST */
  98
  99 /* All the number support there is.
 100  */
 101 #define BIGNUMS
 102
 103 /* GC should relinquish empty cons-pair arenas. */
 104 /* cmm:FIXME look at this after done mangling the GC */
 105 /* #define GC_FREE_SEGMENTS */
 106
 107 /* Provide a scheme-accessible count-down timer that
 108  * generates a pseudo-interrupt.
 109  */
 110 #define TICKS
 111
 112
 113 /* Use engineering notation when converting numbers strings?
 114  */
 115 #undef ENGNOT
 116
 117 \f
 118 /* {Unsupported Options}
 119  *
 120  * These must be defined as given here.
 121  */
 122
 123
 124 #define CCLO
 125
 126 /* Guile Scheme supports the #f/() distinction; Guile Lisp won't.  We
 127    have horrible plans for their unification.  */
 128 #undef SICP
 129
 130 \f
 131
 132 /* Random options (not yet supported or in final form). */
 133
 134 #define STACK_CHECKING
 135 #undef NO_CEVAL_STACK_CHECKING
 136
 137 \f
 138
 139 /* SCM_API is a macro prepended to all function and data definitions
 140    which should be exported or imported in the resulting dynamic link
 141    library (DLL) in the Win32 port. */
 142
 143 #if defined (SCM_IMPORT)
 144 # define SCM_API __declspec (dllimport) extern
 145 #elif defined (SCM_EXPORT) || defined (DLL_EXPORT)
 146 # define SCM_API __declspec (dllexport) extern
 147 #else
 148 # define SCM_API extern
 149 #endif
 150
 151 \f
 152
 153 /* What did the configure script discover about the outside world?  */
 154 #include "libguile/scmconfig.h"
 155
 156 \f
 157
 158 /* {Debugging Options}
 159  *
 160  * These compile time options determine whether to include code that is only
 161  * useful for debugging guile itself or C level extensions to guile.  The
 162  * common prefix for all option macros of this kind is "SCM_DEBUG_".  It is
 163  * guaranteed that a macro named SCM_DEBUG_XXX is defined to be either 0 or 1,
 164  * i. e. there is no need to test for the undefined case.  This allows to use
 165  * these definitions comfortably within code, as in the following example:
 166  *   #define FOO do { if (SCM_DEBUG_XXX) bar(); else baz(); } while (0)
 167  * Any sane compiler will remove the unused branch without any performance
 168  * penalty for the resulting code.
 169  *
 170  * Note:  Some SCM_DEBUG_XXX options are not settable at configure time.
 171  * To change the value of such options you will have to edit this header
 172  * file or give suitable options to make, like:
 173  *   make all CFLAGS="-DSCM_DEBUG_XXX=1 ..."
 174  */
 175
 176
 177 /* The value of SCM_DEBUG determines the default for most of the not yet
 178  * defined debugging options.  This allows, for example, to enable most of the
 179  * debugging options by simply defining SCM_DEBUG as 1.
 180  */
 181 #ifndef SCM_DEBUG
 182 #define SCM_DEBUG 0
 183 #endif
 184
 185 /* If SCM_DEBUG_CELL_ACCESSES is set to 1, cell accesses will perform
 186  * exhaustive parameter checking:  It will be verified that cell parameters
 187  * actually point to a valid heap cell.  Note:  If this option is enabled,
 188  * guile will run about ten times slower than normally.
 189  */
 190 #ifndef SCM_DEBUG_CELL_ACCESSES
 191 #define SCM_DEBUG_CELL_ACCESSES SCM_DEBUG
 192 #endif
 193
 194 /* If SCM_DEBUG_INTERRUPTS is set to 1, with every deferring and allowing of
 195  * interrupts a consistency check will be performed.
 196  */
 197 #ifndef SCM_DEBUG_INTERRUPTS
 198 #define SCM_DEBUG_INTERRUPTS SCM_DEBUG
 199 #endif
 200
 201 /* If SCM_DEBUG_PAIR_ACCESSES is set to 1, accesses to cons cells will be
 202  * exhaustively checked.  Note:  If this option is enabled, guile will run
 203  * slower than normally.
 204  */
 205 #ifndef SCM_DEBUG_PAIR_ACCESSES
 206 #define SCM_DEBUG_PAIR_ACCESSES SCM_DEBUG
 207 #endif
 208
 209 /* If SCM_DEBUG_REST_ARGUMENT is set to 1, functions that take rest arguments
 210  * will check whether the rest arguments are actually passed as a proper list.
 211  * Otherwise, if SCM_DEBUG_REST_ARGUMENT is 0, functions that take rest
 212  * arguments will take it for granted that these are passed as a proper list.
 213  */
 214 #ifndef SCM_DEBUG_REST_ARGUMENT
 215 #define SCM_DEBUG_REST_ARGUMENT SCM_DEBUG
 216 #endif
 217
 218 /* Use this for _compile time_ type checking only, since the compiled result
 219  * will be quite inefficient.  The right way to make use of this option is to
 220  * do a 'make clean; make CFLAGS=-DSCM_DEBUG_TYPING_STRICTNESS=1', fix your
 221  * errors, and then do 'make clean; make'.
 222  */
 223 #ifndef SCM_DEBUG_TYPING_STRICTNESS
 224 #define SCM_DEBUG_TYPING_STRICTNESS 1
 225 #endif
 226
 227 \f
 228
 229 /* {Feature Options}
 230  *
 231  * These compile time options determine whether code for certain features
 232  * should be compiled into guile.  The common prefix for all option macros
 233  * of this kind is "SCM_ENABLE_".  It is guaranteed that a macro named
 234  * SCM_ENABLE_XXX is defined to be either 0 or 1, i. e. there is no need to
 235  * test for the undefined case.  This allows to use these definitions
 236  * comfortably within code, as in the following example:
 237  *   #define FOO do { if (SCM_ENABLE_XXX) bar(); else baz(); } while (0)
 238  * Any sane compiler will remove the unused branch without any performance
 239  * penalty for the resulting code.
 240  *
 241  * Note:  Some SCM_ENABLE_XXX options are not settable at configure time.
 242  * To change the value of such options you will have to edit this header
 243  * file or give suitable options to make, like:
 244  *   make all CFLAGS="-DSCM_ENABLE_XXX=1 ..."
 245  */
 246
 247 /* If SCM_ENABLE_DEPRECATED is set to 1, deprecated code will be included in
 248  * guile, as well as some functions to issue run-time warnings about uses of
 249  * deprecated functions.
 250  */
 251 #ifndef SCM_ENABLE_DEPRECATED
 252 #define SCM_ENABLE_DEPRECATED 0
 253 #endif
 254
 255 \f
 256
 257 /* {Architecture and compiler properties}
 258  *
 259  * Guile as of today can only work on systems which fulfill at least the
 260  * following requirements:
 261  * - long ints have at least 32 bits.
 262  *   Guile's type system is based on this assumption.
 263  * - long ints consist of at least four characters.
 264  *   It is assumed that cells, i. e. pairs of long ints, are eight character
 265  *   aligned, because three bits of a cell pointer are used for type data.
 266  * - sizeof (void*) == sizeof (long int)
 267  *   Pointers are stored in SCM objects, and sometimes SCM objects are passed
 268  *   as void*.  Thus, there has to be a one-to-one correspondence.
 269  * - numbers are encoded using two's complement.
 270  *   The implementation of the bitwise scheme level operations is based on
 271  *   this assumption.
 272  * - ... add more
 273  */
 274
 275 #if SIZEOF_UINTPTR_T != 0 && defined(UINTPTR_MAX) \
 276                           && defined(INTPTR_MAX) \
 277                           && defined(INTPTR_MIN)
 278 /* Used as SCM if available, so we bundle related attributes to avoid possible
 279    type incon[st][oi]n[ae]nce later.  Word in tags.h.  */
 280 #define HAVE_UINTPTR_T 1
 281 #endif
 282
 283 #if SIZEOF_PTRDIFF_T != 0
 284 #define HAVE_PTRDIFF_T 1
 285 #endif
 286
 287 #if SIZEOF_LONG_LONG != 0
 288 #define HAVE_LONG_LONGS 1
 289 #define HAVE_LONG_LONG 1
 290 #endif
 291
 292 #ifndef HAVE_PTRDIFF_T
 293 typedef long ptrdiff_t;
 294 #endif
 295
 296 #ifdef HAVE_LIMITS_H
 297 # include <limits.h>
 298 #endif
 299
 300 #ifdef CHAR_BIT
 301 # define SCM_CHAR_BIT CHAR_BIT
 302 #else
 303 # define SCM_CHAR_BIT 8
 304 #endif
 305
 306 #ifdef LONG_BIT
 307 # define SCM_LONG_BIT LONG_BIT
 308 #else
 309 # define SCM_LONG_BIT (SCM_CHAR_BIT * sizeof (long) / sizeof (char))
 310 #endif
 311
 312 #ifdef UCHAR_MAX
 313 # define SCM_CHAR_CODE_LIMIT (UCHAR_MAX + 1L)
 314 #else
 315 # define SCM_CHAR_CODE_LIMIT 256L
 316 #endif
 317
 318 \f
 319
 320 #ifdef STDC_HEADERS
 321 # include <stdlib.h>
 322 # if HAVE_SYS_TYPES_H
 323 #  include <sys/types.h>
 324 # endif
 325 # if HAVE_SYS_STDTYPES_H
 326 #  include <sys/stdtypes.h>
 327 # endif
 328 #  include <stddef.h>
 329 #endif /* def STDC_HEADERS */
 330
 331 \f
 332
 333 /* Define some additional CPP macros on Win32 platforms. */
 334 #if USE_DLL_IMPORT
 335 # define __REGEX_IMPORT__ 1
 336 # define __CRYPT_IMPORT__ 1
 337 # define __READLINE_IMPORT__ 1
 338 # define QT_IMPORT 1
 339 #endif
 340
 341 \f
 342
 343 #include "libguile/tags.h"
 344
 345 \f
 346 #ifdef vms
 347 # ifndef CHEAP_CONTINUATIONS
 348    typedef int jmp_buf[17];
 349    extern int setjump(jmp_buf env);
 350    extern int longjump(jmp_buf env, int ret);
 351 #  define setjmp setjump
 352 #  define longjmp longjump
 353 # else
 354 #  include <setjmp.h>
 355 # endif
 356 #else                           /* ndef vms */
 357 # ifdef _CRAY1
 358     typedef int jmp_buf[112];
 359     extern int setjump(jmp_buf env);
 360     extern int longjump(jmp_buf env, int ret);
 361 #  define setjmp setjump
 362 #  define longjmp longjump
 363 # else                          /* ndef _CRAY1 */
 364 #  include <setjmp.h>
 365 # endif                         /* ndef _CRAY1 */
 366 #endif                          /* ndef vms */
 367
 368 /* James Clark came up with this neat one instruction fix for
 369  * continuations on the SPARC.  It flushes the register windows so
 370  * that all the state of the process is contained in the stack.
 371  */
 372
 373 #ifdef sparc
 374 # define SCM_FLUSH_REGISTER_WINDOWS asm("ta 3")
 375 #else
 376 # define SCM_FLUSH_REGISTER_WINDOWS /* empty */
 377 #endif
 378
 379 /* If stack is not longword aligned then
 380  */
 381
 382 /* #define SHORT_ALIGN */
 383 #ifdef THINK_C
 384 # define SHORT_ALIGN
 385 #endif
 386 #ifdef MSDOS
 387 # define SHORT_ALIGN
 388 #endif
 389 #ifdef atarist
 390 # define SHORT_ALIGN
 391 #endif
 392
 393 #ifdef SHORT_ALIGN
 394 typedef short SCM_STACKITEM;
 395 #else
 396 typedef long SCM_STACKITEM;
 397 #endif
 398 \f
 399
 400 #define SCM_ASYNC_TICK /*fixme* should change names */ \
 401 do { \
 402   if (scm_root->pending_asyncs) \
 403     scm_async_click (); \
 404 } while (0)
 405
 406
 407 /* Anthony Green writes:
 408    When the compiler sees...
 409            DEFER_INTS;
 410            [critical code here]
 411            ALLOW_INTS;
 412    ...it doesn't actually promise to keep the critical code within the
 413    boundries of the DEFER/ALLOW_INTS instructions. It may very well
 414    schedule it outside of the magic defined in those macros.
 415
 416    However, GCC's volatile asm feature forms a barrier over which code is
 417    never moved. So if you add...
 418            asm ("");
 419    ...to each of the DEFER_INTS and ALLOW_INTS macros, the critical
 420    code will always remain in place.  asm's without inputs or outputs
 421    are implicitly volatile. */
 422 #ifdef __GNUC__
 423 #define SCM_FENCE asm /* volatile */ ("")
 424 #else
 425 #define SCM_FENCE
 426 #endif
 427
 428 #define SCM_DEFER_INTS scm_rec_mutex_lock (&scm_i_defer_mutex);
 429
 430 #define SCM_ALLOW_INTS scm_rec_mutex_unlock (&scm_i_defer_mutex);
 431
 432 #define SCM_REDEFER_INTS SCM_DEFER_INTS
 433
 434 #define SCM_REALLOW_INTS SCM_ALLOW_INTS
 435
 436 #define SCM_TICK \
 437 do { \
 438   SCM_ASYNC_TICK; \
 439   SCM_THREAD_SWITCHING_CODE; \
 440 } while (0)
 441
 442 \f
 443
 444 /* Note: The following needs updating. */
 445
 446 /* Classification of critical sections
 447  *
 448  * When Guile moves to POSIX threads, it won't be possible to prevent
 449  * context switching.  In fact, the whole idea of context switching is
 450  * bogus if threads are run by different processors.  Therefore, we
 451  * must ultimately eliminate all critical sections or enforce them by
 452  * use of mutecis.
 453  *
 454  * All instances of SCM_DEFER_INTS and SCM_ALLOW_INTS should therefore
 455  * be classified and replaced by one of the delimiters below.  If you
 456  * understand what this is all about, I'd like to encourage you to
 457  * help with this task.  The set of classes below must of course be
 458  * incrementally augmented.
 459  *
 460  * MDJ 980419 <djurfeldt@nada.kth.se>
 461  */
 462
 463 /* A sections
 464  *
 465  * Allocation of a cell with type tag in the CAR.
 466  *
 467  * With POSIX threads, each thread will have a private pool of free
 468  * cells.  Therefore, this type of section can be removed.  But!  It
 469  * is important that the CDR is initialized first (with the CAR still
 470  * indicating a free cell) so that we can guarantee a consistent heap
 471  * at all times.
 472  */
 473
 474 #define SCM_ENTER_A_SECTION SCM_CRITICAL_SECTION_START
 475 #define SCM_EXIT_A_SECTION SCM_CRITICAL_SECTION_END
 476
 477 \f
 478
 479 /** SCM_ASSERT
 480  **
 481  **/
 482
 483
 484 #ifdef SCM_RECKLESS
 485 #define SCM_ASSERT(_cond, _arg, _pos, _subr)
 486 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg)
 487 #define SCM_ASRTGO(_cond, _label)
 488 #else
 489 #define SCM_ASSERT(_cond, _arg, _pos, _subr) \
 490         if (!(_cond)) \
 491           scm_wrong_type_arg (_subr, _pos, _arg)
 492 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg) \
 493         if (!(_cond)) \
 494           scm_wrong_type_arg_msg(_subr, _pos, _arg, _msg)
 495 #define SCM_ASRTGO(_cond, _label) \
 496         if (!(_cond)) \
 497           goto _label
 498 #endif
 499
 500 /*
 501  * SCM_WTA_DISPATCH
 502  */
 503
 504 /* Dirk:FIXME:: In all of the SCM_WTA_DISPATCH_* macros it is assumed that
 505  * 'gf' is zero if uninitialized.  It would be cleaner if some valid SCM value
 506  * like SCM_BOOL_F or SCM_UNDEFINED was chosen.
 507  */
 508
 509 SCM_API SCM scm_call_generic_0 (SCM gf);
 510
 511 #define SCM_WTA_DISPATCH_0(gf, subr)                            \
 512   return (SCM_UNPACK (gf)                                       \
 513           ? scm_call_generic_0 ((gf))                           \
 514           : (scm_error_num_args_subr ((subr)), SCM_UNSPECIFIED))
 515 #define SCM_GASSERT0(cond, gf, subr) \
 516   if (!(cond)) SCM_WTA_DISPATCH_0((gf), (subr))
 517
 518 SCM_API SCM scm_call_generic_1 (SCM gf, SCM a1);
 519
 520 #define SCM_WTA_DISPATCH_1(gf, a1, pos, subr)                   \
 521   return (SCM_UNPACK (gf)                                       \
 522           ? scm_call_generic_1 ((gf), (a1))                     \
 523           : (scm_wrong_type_arg ((subr), (pos), (a1)), SCM_UNSPECIFIED))
 524 #define SCM_GASSERT1(cond, gf, a1, pos, subr) \
 525   if (!(cond)) SCM_WTA_DISPATCH_1((gf), (a1), (pos), (subr))
 526
 527 SCM_API SCM scm_call_generic_2 (SCM gf, SCM a1, SCM a2);
 528
 529 #define SCM_WTA_DISPATCH_2(gf, a1, a2, pos, subr)                       \
 530   return (SCM_UNPACK (gf)                                               \
 531           ? scm_call_generic_2 ((gf), (a1), (a2))                       \
 532           : (scm_wrong_type_arg ((subr), (pos),                         \
 533                                  (pos) == SCM_ARG1 ? (a1) : (a2)),      \
 534              SCM_UNSPECIFIED))
 535 #define SCM_GASSERT2(cond, gf, a1, a2, pos, subr) \
 536   if (!(cond)) SCM_WTA_DISPATCH_2((gf), (a1), (a2), (pos), (subr))
 537
 538 SCM_API SCM scm_apply_generic (SCM gf, SCM args);
 539
 540 #define SCM_WTA_DISPATCH_n(gf, args, pos, subr)                           \
 541   return (SCM_UNPACK (gf)                                                 \
 542           ? scm_apply_generic ((gf), (args))                              \
 543           : (scm_wrong_type_arg ((subr), (pos),                           \
 544                                  scm_list_ref ((args),                    \
 545                                                SCM_MAKINUM ((pos) - 1))), \
 546              SCM_UNSPECIFIED))
 547 #define SCM_GASSERTn(cond, gf, args, pos, subr) \
 548   if (!(cond)) SCM_WTA_DISPATCH_n((gf), (args), (pos), (subr))
 549
 550 #ifndef SCM_MAGIC_SNARFER
 551 /* Let these macros pass through if
 552    we are snarfing;  thus we can tell the
 553    difference between the use of an actual
 554    number vs. the use of one of these macros --
 555    actual numbers in SCM_VALIDATE_* and SCM_ASSERT
 556    constructs must match the formal argument name,
 557    but using SCM_ARG* avoids the test */
 558
 559 #define SCM_ARGn                0
 560 #define SCM_ARG1                1
 561 #define SCM_ARG2                2
 562 #define SCM_ARG3                3
 563 #define SCM_ARG4                4
 564 #define SCM_ARG5                5
 565 #define SCM_ARG6                6
 566 #define SCM_ARG7                7
 567
 568 #endif /* SCM_MAGIC_SNARFER */
 569
 570 \f
 571
 572 /* SCM_EXIT_SUCCESS is the default code to return from SCM if no errors
 573  * were encountered.  SCM_EXIT_FAILURE is the default code to return from
 574  * SCM if errors were encountered.  The return code can be explicitly
 575  * specified in a SCM program with (scm_quit <n>).
 576  */
 577
 578 #ifndef SCM_EXIT_SUCCESS
 579 #ifdef vms
 580 #define SCM_EXIT_SUCCESS 1
 581 #else
 582 #define SCM_EXIT_SUCCESS 0
 583 #endif /* def vms */
 584 #endif /* ndef SCM_EXIT_SUCCESS */
 585 #ifndef SCM_EXIT_FAILURE
 586 #ifdef vms
 587 #define SCM_EXIT_FAILURE 2
 588 #else
 589 #define SCM_EXIT_FAILURE 1
 590 #endif /* def vms */
 591 #endif /* ndef SCM_EXIT_FAILURE */
 592
 593 #endif  /* SCM___SCM_H */
 594
 595 /*
 596   Local Variables:
 597   c-file-style: "gnu"
 598   End:
 599 */