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 always defined (typically to
 179  * either 0 or 1), i. e. there is no need to test for the undefined case.
 180  * This allows to use these definitions comfortably within code, as in the
 181  * following example:
 182  *   #define FOO do { if (SCM_DEBUG_XXX) bar(); else baz(); } while (0)
 183  * Any sane compiler will remove the unused branch without any performance
 184  * penalty for the resulting code.
 185  *
 186  * Note:  Some SCM_DEBUG_XXX options are not settable at configure time.
 187  * To change the value of such options you will have to edit this header
 188  * file or give suitable options to make, like:
 189  *   make all CFLAGS="-DSCM_DEBUG_XXX=1 ..."
 190  */
 191
 192
 193 /* The value of SCM_DEBUG determines the default for most of the not yet
 194  * defined debugging options.  This allows, for example, to enable most of the
 195  * debugging options by simply defining SCM_DEBUG as 1.
 196  */
 197 #ifndef SCM_DEBUG
 198 #define SCM_DEBUG 0
 199 #endif
 200
 201 /* If SCM_DEBUG_CELL_ACCESSES is set to 1, cell accesses will perform
 202  * exhaustive parameter checking:  It will be verified that cell parameters
 203  * actually point to a valid heap cell.  Note:  If this option is enabled,
 204  * guile will run about ten times slower than normally.
 205  */
 206 #ifndef SCM_DEBUG_CELL_ACCESSES
 207 #define SCM_DEBUG_CELL_ACCESSES SCM_DEBUG
 208 #endif
 209
 210 /* If SCM_DEBUG_INTERRUPTS is set to 1, with every deferring and allowing of
 211  * interrupts a consistency check will be performed.
 212  */
 213 #ifndef SCM_DEBUG_INTERRUPTS
 214 #define SCM_DEBUG_INTERRUPTS SCM_DEBUG
 215 #endif
 216
 217 /* If SCM_DEBUG_PAIR_ACCESSES is set to 1, accesses to cons cells will be
 218  * exhaustively checked.  Note:  If this option is enabled, guile will run
 219  * slower than normally.
 220  */
 221 #ifndef SCM_DEBUG_PAIR_ACCESSES
 222 #define SCM_DEBUG_PAIR_ACCESSES SCM_DEBUG
 223 #endif
 224
 225 /* If SCM_DEBUG_REST_ARGUMENT is set to 1, functions that take rest arguments
 226  * will check whether the rest arguments are actually passed as a proper list.
 227  * Otherwise, if SCM_DEBUG_REST_ARGUMENT is 0, functions that take rest
 228  * arguments will take it for granted that these are passed as a proper list.
 229  */
 230 #ifndef SCM_DEBUG_REST_ARGUMENT
 231 #define SCM_DEBUG_REST_ARGUMENT SCM_DEBUG
 232 #endif
 233
 234 /* The macro SCM_DEBUG_TYPING_STRICTNESS indicates what level of type checking
 235  * shall be performed with respect to the use of the SCM datatype.  The macro
 236  * may be defined to one of the values 0, 1 and 2.
 237  *
 238  * A value of 0 means that there will be no compile time type checking, since
 239  * the SCM datatype will be declared as an integral type.  This setting should
 240  * only be used on systems, where casting from integral types to pointers may
 241  * lead to loss of bit information.
 242  *
 243  * A value of 1 means that there will an intermediate level of compile time
 244  * type checking, since the SCM datatype will be declared as a pointer to an
 245  * undefined struct.  This setting is the default, since it does not cost
 246  * anything in terms of performance or code size.
 247  *
 248  * A value of 2 provides a maximum level of compile time type checking since
 249  * the SCM datatype will be declared as a struct.  This setting should be used
 250  * for _compile time_ type checking only, since the compiled result is likely
 251  * to be quite inefficient.  The right way to make use of this option is to do
 252  * a 'make clean; make CFLAGS=-DSCM_DEBUG_TYPING_STRICTNESS=2', fix your
 253  * errors, and then do 'make clean; make'.
 254  */
 255 #ifndef SCM_DEBUG_TYPING_STRICTNESS
 256 #define SCM_DEBUG_TYPING_STRICTNESS 1
 257 #endif
 258
 259 \f
 260
 261 /* {Feature Options}
 262  *
 263  * These compile time options determine whether code for certain features
 264  * should be compiled into guile.  The common prefix for all option macros
 265  * of this kind is "SCM_ENABLE_".  It is guaranteed that a macro named
 266  * SCM_ENABLE_XXX is defined to be either 0 or 1, i. e. there is no need to
 267  * test for the undefined case.  This allows to use these definitions
 268  * comfortably within code, as in the following example:
 269  *   #define FOO do { if (SCM_ENABLE_XXX) bar(); else baz(); } while (0)
 270  * Any sane compiler will remove the unused branch without any performance
 271  * penalty for the resulting code.
 272  *
 273  * Note:  Some SCM_ENABLE_XXX options are not settable at configure time.
 274  * To change the value of such options you will have to edit this header
 275  * file or give suitable options to make, like:
 276  *   make all CFLAGS="-DSCM_ENABLE_XXX=1 ..."
 277  */
 278
 279 /* If SCM_ENABLE_DEPRECATED is set to 1, deprecated code will be included in
 280  * guile, as well as some functions to issue run-time warnings about uses of
 281  * deprecated functions.
 282  */
 283 #ifndef SCM_ENABLE_DEPRECATED
 284 #define SCM_ENABLE_DEPRECATED 0
 285 #endif
 286
 287 \f
 288
 289 /* {Architecture and compiler properties}
 290  *
 291  * Guile as of today can only work on systems which fulfill at least the
 292  * following requirements:
 293  * - long ints have at least 32 bits.
 294  *   Guile's type system is based on this assumption.
 295  * - long ints consist of at least four characters.
 296  *   It is assumed that cells, i. e. pairs of long ints, are eight character
 297  *   aligned, because three bits of a cell pointer are used for type data.
 298  * - sizeof (void*) == sizeof (long int)
 299  *   Pointers are stored in SCM objects, and sometimes SCM objects are passed
 300  *   as void*.  Thus, there has to be a one-to-one correspondence.
 301  * - numbers are encoded using two's complement.
 302  *   The implementation of the bitwise scheme level operations is based on
 303  *   this assumption.
 304  * - ... add more
 305  */
 306
 307 #ifdef CHAR_BIT
 308 # define SCM_CHAR_BIT CHAR_BIT
 309 #else
 310 # define SCM_CHAR_BIT 8
 311 #endif
 312
 313 #ifdef LONG_BIT
 314 # define SCM_LONG_BIT LONG_BIT
 315 #else
 316 # define SCM_LONG_BIT (SCM_CHAR_BIT * sizeof (long) / sizeof (char))
 317 #endif
 318
 319 #ifdef UCHAR_MAX
 320 # define SCM_CHAR_CODE_LIMIT (UCHAR_MAX + 1L)
 321 #else
 322 # define SCM_CHAR_CODE_LIMIT 256L
 323 #endif
 324
 325 \f
 326
 327 #include "libguile/tags.h"
 328
 329 \f
 330 #ifdef vms
 331 # ifndef CHEAP_CONTINUATIONS
 332    typedef int jmp_buf[17];
 333    extern int setjump(jmp_buf env);
 334    extern int longjump(jmp_buf env, int ret);
 335 #  define setjmp setjump
 336 #  define longjmp longjump
 337 # else
 338 #  include <setjmp.h>
 339 # endif
 340 #else                           /* ndef vms */
 341 # ifdef _CRAY1
 342     typedef int jmp_buf[112];
 343     extern int setjump(jmp_buf env);
 344     extern int longjump(jmp_buf env, int ret);
 345 #  define setjmp setjump
 346 #  define longjmp longjump
 347 # else                          /* ndef _CRAY1 */
 348 #  include <setjmp.h>
 349 # endif                         /* ndef _CRAY1 */
 350 #endif                          /* ndef vms */
 351
 352 /* James Clark came up with this neat one instruction fix for
 353  * continuations on the SPARC.  It flushes the register windows so
 354  * that all the state of the process is contained in the stack.
 355  */
 356
 357 #if defined (sparc) || defined (__sparc__) || defined (__sparc)
 358 # define SCM_FLUSH_REGISTER_WINDOWS asm("ta 3")
 359 #else
 360 # define SCM_FLUSH_REGISTER_WINDOWS /* empty */
 361 #endif
 362
 363 /* If stack is not longword aligned then
 364  */
 365
 366 /* #define SHORT_ALIGN */
 367 #ifdef THINK_C
 368 # define SHORT_ALIGN
 369 #endif
 370 #ifdef MSDOS
 371 # define SHORT_ALIGN
 372 #endif
 373 #ifdef atarist
 374 # define SHORT_ALIGN
 375 #endif
 376
 377 #ifdef SHORT_ALIGN
 378 typedef short SCM_STACKITEM;
 379 #else
 380 typedef long SCM_STACKITEM;
 381 #endif
 382 \f
 383
 384 #define SCM_ASYNC_TICK /*fixme* should change names */ \
 385 do { \
 386   if (scm_root->pending_asyncs) \
 387     scm_async_click (); \
 388 } while (0)
 389
 390
 391 /* Anthony Green writes:
 392    When the compiler sees...
 393            DEFER_INTS;
 394            [critical code here]
 395            ALLOW_INTS;
 396    ...it doesn't actually promise to keep the critical code within the
 397    boundries of the DEFER/ALLOW_INTS instructions. It may very well
 398    schedule it outside of the magic defined in those macros.
 399
 400    However, GCC's volatile asm feature forms a barrier over which code is
 401    never moved. So if you add...
 402            asm ("");
 403    ...to each of the DEFER_INTS and ALLOW_INTS macros, the critical
 404    code will always remain in place.  asm's without inputs or outputs
 405    are implicitly volatile. */
 406 #ifdef __GNUC__
 407 #define SCM_FENCE asm /* volatile */ ("")
 408 #else
 409 #define SCM_FENCE
 410 #endif
 411
 412 #define SCM_DEFER_INTS scm_rec_mutex_lock (&scm_i_defer_mutex);
 413
 414 #define SCM_ALLOW_INTS scm_rec_mutex_unlock (&scm_i_defer_mutex);
 415
 416 #define SCM_REDEFER_INTS SCM_DEFER_INTS
 417
 418 #define SCM_REALLOW_INTS SCM_ALLOW_INTS
 419
 420 #define SCM_TICK \
 421 do { \
 422   SCM_ASYNC_TICK; \
 423   SCM_THREAD_SWITCHING_CODE; \
 424 } while (0)
 425
 426 \f
 427
 428 /* Note: The following needs updating. */
 429
 430 /* Classification of critical sections
 431  *
 432  * When Guile moves to POSIX threads, it won't be possible to prevent
 433  * context switching.  In fact, the whole idea of context switching is
 434  * bogus if threads are run by different processors.  Therefore, we
 435  * must ultimately eliminate all critical sections or enforce them by
 436  * use of mutecis.
 437  *
 438  * All instances of SCM_DEFER_INTS and SCM_ALLOW_INTS should therefore
 439  * be classified and replaced by one of the delimiters below.  If you
 440  * understand what this is all about, I'd like to encourage you to
 441  * help with this task.  The set of classes below must of course be
 442  * incrementally augmented.
 443  *
 444  * MDJ 980419 <djurfeldt@nada.kth.se>
 445  */
 446
 447 /* A sections
 448  *
 449  * Allocation of a cell with type tag in the CAR.
 450  *
 451  * With POSIX threads, each thread will have a private pool of free
 452  * cells.  Therefore, this type of section can be removed.  But!  It
 453  * is important that the CDR is initialized first (with the CAR still
 454  * indicating a free cell) so that we can guarantee a consistent heap
 455  * at all times.
 456  */
 457
 458 #define SCM_ENTER_A_SECTION SCM_CRITICAL_SECTION_START
 459 #define SCM_EXIT_A_SECTION SCM_CRITICAL_SECTION_END
 460
 461 \f
 462
 463 /** SCM_ASSERT
 464  **
 465  **/
 466
 467
 468 #ifdef SCM_RECKLESS
 469 #define SCM_ASSERT(_cond, _arg, _pos, _subr)
 470 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg)
 471 #define SCM_ASRTGO(_cond, _label)
 472 #else
 473 #define SCM_ASSERT(_cond, _arg, _pos, _subr) \
 474         if (!(_cond)) \
 475           scm_wrong_type_arg (_subr, _pos, _arg)
 476 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg) \
 477         if (!(_cond)) \
 478           scm_wrong_type_arg_msg(_subr, _pos, _arg, _msg)
 479 #define SCM_ASRTGO(_cond, _label) \
 480         if (!(_cond)) \
 481           goto _label
 482 #endif
 483
 484 /*
 485  * SCM_WTA_DISPATCH
 486  */
 487
 488 /* Dirk:FIXME:: In all of the SCM_WTA_DISPATCH_* macros it is assumed that
 489  * 'gf' is zero if uninitialized.  It would be cleaner if some valid SCM value
 490  * like SCM_BOOL_F or SCM_UNDEFINED was chosen.
 491  */
 492
 493 SCM_API SCM scm_call_generic_0 (SCM gf);
 494
 495 #define SCM_WTA_DISPATCH_0(gf, subr)                            \
 496   return (SCM_UNPACK (gf)                                       \
 497           ? scm_call_generic_0 ((gf))                           \
 498           : (scm_error_num_args_subr ((subr)), SCM_UNSPECIFIED))
 499 #define SCM_GASSERT0(cond, gf, subr) \
 500   if (!(cond)) SCM_WTA_DISPATCH_0((gf), (subr))
 501
 502 SCM_API SCM scm_call_generic_1 (SCM gf, SCM a1);
 503
 504 #define SCM_WTA_DISPATCH_1(gf, a1, pos, subr)                   \
 505   return (SCM_UNPACK (gf)                                       \
 506           ? scm_call_generic_1 ((gf), (a1))                     \
 507           : (scm_wrong_type_arg ((subr), (pos), (a1)), SCM_UNSPECIFIED))
 508 #define SCM_GASSERT1(cond, gf, a1, pos, subr) \
 509   if (!(cond)) SCM_WTA_DISPATCH_1((gf), (a1), (pos), (subr))
 510
 511 SCM_API SCM scm_call_generic_2 (SCM gf, SCM a1, SCM a2);
 512
 513 #define SCM_WTA_DISPATCH_2(gf, a1, a2, pos, subr)                       \
 514   return (SCM_UNPACK (gf)                                               \
 515           ? scm_call_generic_2 ((gf), (a1), (a2))                       \
 516           : (scm_wrong_type_arg ((subr), (pos),                         \
 517                                  (pos) == SCM_ARG1 ? (a1) : (a2)),      \
 518              SCM_UNSPECIFIED))
 519 #define SCM_GASSERT2(cond, gf, a1, a2, pos, subr) \
 520   if (!(cond)) SCM_WTA_DISPATCH_2((gf), (a1), (a2), (pos), (subr))
 521
 522 SCM_API SCM scm_apply_generic (SCM gf, SCM args);
 523
 524 #define SCM_WTA_DISPATCH_n(gf, args, pos, subr)                           \
 525   return (SCM_UNPACK (gf)                                                 \
 526           ? scm_apply_generic ((gf), (args))                              \
 527           : (scm_wrong_type_arg ((subr), (pos),                           \
 528                                  scm_list_ref ((args),                    \
 529                                                SCM_MAKINUM ((pos) - 1))), \
 530              SCM_UNSPECIFIED))
 531 #define SCM_GASSERTn(cond, gf, args, pos, subr) \
 532   if (!(cond)) SCM_WTA_DISPATCH_n((gf), (args), (pos), (subr))
 533
 534 #ifndef SCM_MAGIC_SNARFER
 535 /* Let these macros pass through if
 536    we are snarfing;  thus we can tell the
 537    difference between the use of an actual
 538    number vs. the use of one of these macros --
 539    actual numbers in SCM_VALIDATE_* and SCM_ASSERT
 540    constructs must match the formal argument name,
 541    but using SCM_ARG* avoids the test */
 542
 543 #define SCM_ARGn                0
 544 #define SCM_ARG1                1
 545 #define SCM_ARG2                2
 546 #define SCM_ARG3                3
 547 #define SCM_ARG4                4
 548 #define SCM_ARG5                5
 549 #define SCM_ARG6                6
 550 #define SCM_ARG7                7
 551
 552 #endif /* SCM_MAGIC_SNARFER */
 553
 554 \f
 555
 556 /* SCM_EXIT_SUCCESS is the default code to return from SCM if no errors
 557  * were encountered.  SCM_EXIT_FAILURE is the default code to return from
 558  * SCM if errors were encountered.  The return code can be explicitly
 559  * specified in a SCM program with (scm_quit <n>).
 560  */
 561
 562 #ifndef SCM_EXIT_SUCCESS
 563 #ifdef vms
 564 #define SCM_EXIT_SUCCESS 1
 565 #else
 566 #define SCM_EXIT_SUCCESS 0
 567 #endif /* def vms */
 568 #endif /* ndef SCM_EXIT_SUCCESS */
 569 #ifndef SCM_EXIT_FAILURE
 570 #ifdef vms
 571 #define SCM_EXIT_FAILURE 2
 572 #else
 573 #define SCM_EXIT_FAILURE 1
 574 #endif /* def vms */
 575 #endif /* ndef SCM_EXIT_FAILURE */
 576
 577 #endif  /* SCM___SCM_H */
 578
 579 /*
 580   Local Variables:
 581   c-file-style: "gnu"
 582   End:
 583 */