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, 2003, 2006,
   7  *   2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public License
  11  * as published by the Free Software Foundation; either version 3 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  22  * 02110-1301 USA
  23  */
  24
  25 \f
  26
  27 /**********************************************************************
  28  This file is Guile's central public header.
  29
  30  When included by other files, this file should preceed any include
  31  other than __scm.h.
  32
  33  Under *NO* circumstances should new items be added to the global
  34  namespace (via adding #define, typedef, or similar to this file) with
  35  generic names.  This usually means that any new names should be
  36  prefixed by either SCM_ or GUILE_.  i.e. do *not* #define HAVE_FOO or
  37  SIZEOF_BAR.  See configure.in, gen-scmconfig.h.in, and
  38  gen-scmconfig.c for examples of how to properly handle this issue.
  39  The main documentation is in gen-scmconfig.c.
  40
  41  "What's the difference between _scm.h and __scm.h?"
  42
  43    _scm.h is not installed; it's only visible to the libguile sources
  44    themselves, and it includes config.h, the private config header.
  45
  46    __scm.h is installed, and is #included by <libguile.h>.  If both
  47    the client and libguile need some piece of information, and it
  48    doesn't fit well into the header file for any particular module, it
  49    should go in __scm.h.  __scm.h includes scmconfig.h, the public
  50    config header.
  51  **********************************************************************/
  52
  53 /* What did the configure script discover about the outside world?  */
  54 #include "libguile/scmconfig.h"
  55
  56 \f
  57
  58 /* {Compiler hints}
  59  *
  60  * The following macros are used to provide additional information for the
  61  * compiler, which may help to do better error checking and code
  62  * optimization.  A second benefit of these macros is, that they also provide
  63  * additional information to the developers.
  64  */
  65
  66 /* Return true (non-zero) if GCC version MAJ.MIN or later is being used
  67  * (macro taken from glibc.)  */
  68 #if defined __GNUC__ && defined __GNUC_MINOR__
  69 # define SCM_GNUC_PREREQ(maj, min) \
  70         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
  71 #else
  72 # define SCM_GNUC_PREREQ(maj, min) 0
  73 #endif
  74
  75 /* The macro SCM_NORETURN indicates that a function will never return.
  76  * Examples:
  77  *   1) int foo (char arg) SCM_NORETURN;
  78  */
  79 #ifdef __GNUC__
  80 #define SCM_NORETURN __attribute__ ((noreturn))
  81 #else
  82 #define SCM_NORETURN
  83 #endif
  84
  85 /* The macro SCM_UNUSED indicates that a function, function argument or
  86  * variable may potentially be unused.
  87  * Examples:
  88  *   1) static int unused_function (char arg) SCM_UNUSED;
  89  *   2) int foo (char unused_argument SCM_UNUSED);
  90  *   3) int unused_variable SCM_UNUSED;
  91  */
  92 #ifdef __GNUC__
  93 #define SCM_UNUSED __attribute__ ((unused))
  94 #else
  95 #define SCM_UNUSED
  96 #endif
  97
  98
  99 /* The SCM_EXPECT macros provide branch prediction hints to the compiler.  To
 100  * use only in places where the result of the expression under "normal"
 101  * circumstances is known.  */
 102 #if SCM_GNUC_PREREQ (3, 0)
 103 # define SCM_EXPECT    __builtin_expect
 104 #else
 105 # define SCM_EXPECT(_expr, _value) (_expr)
 106 #endif
 107
 108 #define SCM_LIKELY(_expr)    SCM_EXPECT ((_expr), 1)
 109 #define SCM_UNLIKELY(_expr)  SCM_EXPECT ((_expr), 0)
 110
 111 /* The SCM_INTERNAL macro makes it possible to explicitly declare a function
 112  * as having "internal" linkage.  However our current tack on this problem is
 113  * to use GCC 4's -fvisibility=hidden, making functions internal by default,
 114  * and then SCM_API marks them for export. */
 115 #define SCM_INTERNAL  extern
 116
 117 /* The SCM_DEPRECATED macro is used in declarations of deprecated functions
 118  * or variables.  Defining `SCM_BUILDING_DEPRECATED_CODE' allows deprecated
 119  * functions to be implemented in terms of deprecated functions, and allows
 120  * deprecated functions to be referred to by `scm_c_define_gsubr ()'.  */
 121 #if !defined (SCM_BUILDING_DEPRECATED_CODE) && SCM_GNUC_PREREQ (3, 0)
 122 # define SCM_DEPRECATED  SCM_API __attribute__ ((__deprecated__))
 123 #else
 124 # define SCM_DEPRECATED  SCM_API
 125 #endif
 126
 127 /* The SCM_ALIGNED macro, when defined, can be used to instruct the compiler
 128  * to honor the given alignment constraint.  */
 129 #if defined __GNUC__
 130 # define SCM_ALIGNED(x)  __attribute__ ((aligned (x)))
 131 #elif defined __INTEL_COMPILER
 132 # define SCM_ALIGNED(x)  __declspec (align (x))
 133 #else
 134 /* Don't know how to align things.  */
 135 # undef SCM_ALIGNED
 136 #endif
 137
 138 /* The SCM_MALLOC macro can be used in function declarations to tell the
 139  * compiler that a function may be treated as if any non-NULL pointer it returns
 140  * cannot alias any other pointer valid when the function returns.  */
 141 #if SCM_GNUC_PREREQ (3, 0)
 142 # define SCM_MALLOC  __attribute__ ((__malloc__))
 143 #else
 144 # define SCM_MALLOC
 145 #endif
 146
 147 \f
 148 /* {Supported Options}
 149  *
 150  * These may be defined or undefined.
 151  */
 152
 153 /* #define GUILE_DEBUG_FREELIST */
 154
 155
 156 /* Use engineering notation when converting numbers strings?
 157  */
 158 #undef ENGNOT
 159
 160 \f
 161 /* {Unsupported Options}
 162  *
 163  * These must be defined as given here.
 164  */
 165
 166
 167 /* Guile Scheme supports the #f/() distinction; Guile Lisp won't.  We
 168    have horrible plans for their unification.  */
 169 #undef SICP
 170
 171 \f
 172
 173 /* Random options (not yet supported or in final form). */
 174
 175 #define STACK_CHECKING
 176 #undef NO_CEVAL_STACK_CHECKING
 177
 178 \f
 179
 180 /* SCM_API is a macro prepended to all function and data definitions
 181    which should be exported from libguile. */
 182
 183 #if defined BUILDING_LIBGUILE && defined HAVE_VISIBILITY
 184 # define SCM_API extern __attribute__((__visibility__("default")))
 185 #elif defined BUILDING_LIBGUILE && defined _MSC_VER
 186 # define SCM_API __declspec(dllexport) extern
 187 #elif defined _MSC_VER
 188 # define SCM_API __declspec(dllimport) extern
 189 #else
 190 # define SCM_API extern
 191 #endif
 192
 193 \f
 194
 195 /* {Debugging Options}
 196  *
 197  * These compile time options determine whether to include code that is only
 198  * useful for debugging guile itself or C level extensions to guile.  The
 199  * common prefix for all option macros of this kind is "SCM_DEBUG_".  It is
 200  * guaranteed that a macro named SCM_DEBUG_XXX is always defined (typically to
 201  * either 0 or 1), i. e. there is no need to test for the undefined case.
 202  * This allows to use these definitions comfortably within code, as in the
 203  * following example:
 204  *   #define FOO do { if (SCM_DEBUG_XXX) bar(); else baz(); } while (0)
 205  * Any sane compiler will remove the unused branch without any performance
 206  * penalty for the resulting code.
 207  *
 208  * Note:  Some SCM_DEBUG_XXX options are not settable at configure time.
 209  * To change the value of such options you will have to edit this header
 210  * file or give suitable options to make, like:
 211  *   make all CFLAGS="-DSCM_DEBUG_XXX=1 ..."
 212  */
 213
 214
 215 /* The value of SCM_DEBUG determines the default for most of the not yet
 216  * defined debugging options.  This allows, for example, to enable most of the
 217  * debugging options by simply defining SCM_DEBUG as 1.
 218  */
 219 #ifndef SCM_DEBUG
 220 #define SCM_DEBUG 0
 221 #endif
 222
 223 /* For debugging purposes: define this is to ensure nobody is using
 224  * the mark bits outside of the marking phase.  This is meant for
 225  * debugging purposes only.
 226  */
 227 #ifndef SCM_DEBUG_MARKING_API
 228 #define SCM_DEBUG_MARKING_API 0
 229 #endif
 230
 231 /* If SCM_DEBUG_CELL_ACCESSES is set to 1, cell accesses will perform
 232  * exhaustive parameter checking:  It will be verified that cell parameters
 233  * actually point to a valid heap cell.  Note:  If this option is enabled,
 234  * guile will run about ten times slower than normally.
 235  */
 236 #ifndef SCM_DEBUG_CELL_ACCESSES
 237 #define SCM_DEBUG_CELL_ACCESSES SCM_DEBUG
 238 #endif
 239
 240 /* If SCM_DEBUG_INTERRUPTS is set to 1, with every deferring and allowing of
 241  * interrupts a consistency check will be performed.
 242  */
 243 #ifndef SCM_DEBUG_INTERRUPTS
 244 #define SCM_DEBUG_INTERRUPTS SCM_DEBUG
 245 #endif
 246
 247 /* If SCM_DEBUG_PAIR_ACCESSES is set to 1, accesses to cons cells will be
 248  * exhaustively checked.  Note:  If this option is enabled, guile will run
 249  * slower than normally.
 250  */
 251 #ifndef SCM_DEBUG_PAIR_ACCESSES
 252 #define SCM_DEBUG_PAIR_ACCESSES SCM_DEBUG
 253 #endif
 254
 255 /* If SCM_DEBUG_REST_ARGUMENT is set to 1, functions that take rest arguments
 256  * will check whether the rest arguments are actually passed as a proper list.
 257  * Otherwise, if SCM_DEBUG_REST_ARGUMENT is 0, functions that take rest
 258  * arguments will take it for granted that these are passed as a proper list.
 259  */
 260 #ifndef SCM_DEBUG_REST_ARGUMENT
 261 #define SCM_DEBUG_REST_ARGUMENT SCM_DEBUG
 262 #endif
 263
 264 /* The macro SCM_DEBUG_TYPING_STRICTNESS indicates what level of type checking
 265  * shall be performed with respect to the use of the SCM datatype.  The macro
 266  * may be defined to one of the values 0, 1 and 2.
 267  *
 268  * A value of 0 means that there will be no compile time type checking, since
 269  * the SCM datatype will be declared as an integral type.  This setting should
 270  * only be used on systems, where casting from integral types to pointers may
 271  * lead to loss of bit information.
 272  *
 273  * A value of 1 means that there will an intermediate level of compile time
 274  * type checking, since the SCM datatype will be declared as a pointer to an
 275  * undefined struct.  This setting is the default, since it does not cost
 276  * anything in terms of performance or code size.
 277  *
 278  * A value of 2 provides a maximum level of compile time type checking since
 279  * the SCM datatype will be declared as a struct.  This setting should be used
 280  * for _compile time_ type checking only, since the compiled result is likely
 281  * to be quite inefficient.  The right way to make use of this option is to do
 282  * a 'make clean; make CFLAGS=-DSCM_DEBUG_TYPING_STRICTNESS=2', fix your
 283  * errors, and then do 'make clean; make'.
 284  */
 285 #ifndef SCM_DEBUG_TYPING_STRICTNESS
 286 #define SCM_DEBUG_TYPING_STRICTNESS 1
 287 #endif
 288
 289 /* If SCM_DEBUG_DEBUGGING_SUPPORT is set to 1, guile will provide a set of
 290  * special functions that support debugging with a debugger like gdb or
 291  * debugging of guile internals on the scheme level.  The behaviour of guile
 292  * is not changed by this macro, only the set of functions that are available
 293  * will differ.  All functions that are introduced this way have the prefix
 294  * 'scm_dbg_' on the C level and the prefix 'dbg-' on the scheme level.  This
 295  * allows to easily determine the set of support functions, given that your
 296  * debugger or repl provide automatic name completion.  Note that these
 297  * functions are intended to be used during interactive debugging sessions
 298  * only.  They are not considered part of guile's official API.  They may
 299  * change or disappear without notice or deprecation phase.
 300  */
 301 #ifndef SCM_DEBUG_DEBUGGING_SUPPORT
 302 #define SCM_DEBUG_DEBUGGING_SUPPORT SCM_DEBUG
 303 #endif
 304
 305 \f
 306
 307 /* {Feature Options}
 308  *
 309  * These compile time options determine whether code for certain features
 310  * should be compiled into guile.  The common prefix for all option macros
 311  * of this kind is "SCM_ENABLE_".  It is guaranteed that a macro named
 312  * SCM_ENABLE_XXX is defined to be either 0 or 1, i. e. there is no need to
 313  * test for the undefined case.  This allows to use these definitions
 314  * comfortably within code, as in the following example:
 315  *   #define FOO do { if (SCM_ENABLE_XXX) bar(); else baz(); } while (0)
 316  * Any sane compiler will remove the unused branch without any performance
 317  * penalty for the resulting code.
 318  *
 319  * Note:  Some SCM_ENABLE_XXX options are not settable at configure time.
 320  * To change the value of such options you will have to edit this header
 321  * file or give suitable options to make, like:
 322  *   make all CFLAGS="-DSCM_ENABLE_XXX=1 ..."
 323  */
 324
 325 /* If SCM_ENABLE_DEPRECATED is set to 1, deprecated code will be included in
 326  * guile, as well as some functions to issue run-time warnings about uses of
 327  * deprecated functions.
 328  */
 329 #ifndef SCM_ENABLE_DEPRECATED
 330 #define SCM_ENABLE_DEPRECATED 0
 331 #endif
 332
 333 \f
 334
 335 /* {Architecture and compiler properties}
 336  *
 337  * Guile as of today can only work on systems which fulfill at least the
 338  * following requirements:
 339  *
 340  * - scm_t_bits and SCM variables have at least 32 bits.
 341  *   Guile's type system is based on this assumption.
 342  *
 343  * - sizeof (scm_t_bits) >= sizeof (void*) and sizeof (SCM) >= sizeof (void*)
 344  *   Guile's type system is based on this assumption, since it must be
 345  *   possible to store pointers to cells on the heap in scm_t_bits and SCM
 346  *   variables.
 347  *
 348  * - sizeof (scm_t_bits) >= 4 and sizeof (scm_t_bits) is a power of 2.
 349  *   Guile's type system is based on this assumption.  In particular, it is
 350  *   assumed that cells, i. e. pairs of scm_t_bits variables, are eight
 351  *   character aligned.  This is because three bits of a scm_t_bits variable
 352  *   that is holding a pointer to a cell on the heap must be available for
 353  *   storing type data.
 354  *
 355  * - sizeof (scm_t_bits) <= sizeof (void*) and sizeof (SCM) <= sizeof (void*)
 356  *   In some parts of guile, scm_t_bits and SCM variables are passed to
 357  *   functions as void* arguments.  Together with the requirement above, this
 358  *   requires a one-to-one correspondence between the size of a void* and the
 359  *   sizes of scm_t_bits and SCM variables.
 360  *
 361  * - numbers are encoded using two's complement.
 362  *   The implementation of the bitwise scheme level operations is based on
 363  *   this assumption.
 364  *
 365  * - ... add more
 366  */
 367
 368 #ifdef CHAR_BIT
 369 # define SCM_CHAR_BIT CHAR_BIT
 370 #else
 371 # define SCM_CHAR_BIT 8
 372 #endif
 373
 374 #ifdef LONG_BIT
 375 # define SCM_LONG_BIT LONG_BIT
 376 #else
 377 # define SCM_LONG_BIT (SCM_CHAR_BIT * sizeof (long) / sizeof (char))
 378 #endif
 379
 380 #ifdef UCHAR_MAX
 381 # define SCM_CHAR_CODE_LIMIT (UCHAR_MAX + 1L)
 382 #else
 383 # define SCM_CHAR_CODE_LIMIT 256L
 384 #endif
 385
 386 #define SCM_I_UTYPE_MAX(type)      ((type)-1)
 387 #define SCM_I_TYPE_MAX(type,umax)  ((type)((umax)/2))
 388 #define SCM_I_TYPE_MIN(type,umax)  (-((type)((umax)/2))-1)
 389
 390 #define SCM_T_UINT8_MAX   SCM_I_UTYPE_MAX(scm_t_uint8)
 391 #define SCM_T_INT8_MIN    SCM_I_TYPE_MIN(scm_t_int8,SCM_T_UINT8_MAX)
 392 #define SCM_T_INT8_MAX    SCM_I_TYPE_MAX(scm_t_int8,SCM_T_UINT8_MAX)
 393
 394 #define SCM_T_UINT16_MAX  SCM_I_UTYPE_MAX(scm_t_uint16)
 395 #define SCM_T_INT16_MIN   SCM_I_TYPE_MIN(scm_t_int16,SCM_T_UINT16_MAX)
 396 #define SCM_T_INT16_MAX   SCM_I_TYPE_MAX(scm_t_int16,SCM_T_UINT16_MAX)
 397
 398 #define SCM_T_UINT32_MAX  SCM_I_UTYPE_MAX(scm_t_uint32)
 399 #define SCM_T_INT32_MIN   SCM_I_TYPE_MIN(scm_t_int32,SCM_T_UINT32_MAX)
 400 #define SCM_T_INT32_MAX   SCM_I_TYPE_MAX(scm_t_int32,SCM_T_UINT32_MAX)
 401
 402 #define SCM_T_UINT64_MAX  SCM_I_UTYPE_MAX(scm_t_uint64)
 403 #define SCM_T_INT64_MIN   SCM_I_TYPE_MIN(scm_t_int64,SCM_T_UINT64_MAX)
 404 #define SCM_T_INT64_MAX   SCM_I_TYPE_MAX(scm_t_int64,SCM_T_UINT64_MAX)
 405
 406 #if SCM_SIZEOF_LONG_LONG
 407 #define SCM_I_ULLONG_MAX  SCM_I_UTYPE_MAX(unsigned long long)
 408 #define SCM_I_LLONG_MIN   SCM_I_TYPE_MIN(long long,SCM_I_ULLONG_MAX)
 409 #define SCM_I_LLONG_MAX   SCM_I_TYPE_MAX(long long,SCM_I_ULLONG_MAX)
 410 #endif
 411
 412 #define SCM_T_UINTMAX_MAX SCM_I_UTYPE_MAX(scm_t_uintmax)
 413 #define SCM_T_INTMAX_MIN  SCM_I_TYPE_MIN(scm_t_intmax,SCM_T_UINTMAX_MAX)
 414 #define SCM_T_INTMAX_MAX  SCM_I_TYPE_MAX(scm_t_intmax,SCM_T_UINTMAX_MAX)
 415
 416 #define SCM_T_UINTPTR_MAX SCM_I_UTYPE_MAX(scm_t_uintptr)
 417 #define SCM_T_INTPTR_MIN  SCM_I_TYPE_MIN(scm_t_intptr,SCM_T_UINTPTR_MAX)
 418 #define SCM_T_INTPTR_MAX  SCM_I_TYPE_MAX(scm_t_intptr,SCM_T_UINTPTR_MAX)
 419
 420 #define SCM_I_SIZE_MAX    SCM_I_UTYPE_MAX(size_t)
 421 #define SCM_I_SSIZE_MIN   SCM_I_TYPE_MIN(ssize_t,SCM_I_SIZE_MAX)
 422 #define SCM_I_SSIZE_MAX   SCM_I_TYPE_MAX(ssize_t,SCM_I_SIZE_MAX)
 423
 424 \f
 425
 426 #include "libguile/tags.h"
 427
 428
 429 /* The type of subrs, i.e., Scheme procedures implemented in C.  Empty
 430    function declarators are used internally for pointers to functions of
 431    any arity.  However, these are equivalent to `(void)' in C++, are
 432    obsolescent as of C99, and trigger `strict-prototypes' GCC warnings
 433    (bug #23681).  */
 434
 435 #ifdef BUILDING_LIBGUILE
 436 typedef SCM (* scm_t_subr) ();
 437 #else
 438 typedef void *scm_t_subr;
 439 #endif
 440
 441 \f
 442 #ifdef vms
 443 # ifndef CHEAP_CONTINUATIONS
 444    typedef int jmp_buf[17];
 445    extern int setjump(jmp_buf env);
 446    extern int longjump(jmp_buf env, int ret);
 447 #  define setjmp setjump
 448 #  define longjmp longjump
 449 # else
 450 #  include <setjmp.h>
 451 # endif
 452 #else                           /* ndef vms */
 453 # ifdef _CRAY1
 454     typedef int jmp_buf[112];
 455     extern int setjump(jmp_buf env);
 456     extern int longjump(jmp_buf env, int ret);
 457 #  define setjmp setjump
 458 #  define longjmp longjump
 459 # else                          /* ndef _CRAY1 */
 460 #  if defined (__ia64__)
 461 /* For IA64, emulate the setjmp API using getcontext. */
 462 #   include <signal.h>
 463 #   include <ucontext.h>
 464     typedef struct {
 465       ucontext_t ctx;
 466       int fresh;
 467     } scm_i_jmp_buf;
 468 #   define SCM_I_SETJMP(JB)                             \
 469       ( (JB).fresh = 1,                                 \
 470         getcontext (&((JB).ctx)),                       \
 471         ((JB).fresh ? ((JB).fresh = 0, 0) : 1) )
 472 #   define SCM_I_LONGJMP(JB,VAL) scm_ia64_longjmp (&(JB), VAL)
 473     void scm_ia64_longjmp (scm_i_jmp_buf *, int);
 474 #  else                         /* ndef __ia64__ */
 475 #   include <setjmp.h>
 476 #  endif                        /* ndef __ia64__ */
 477 # endif                         /* ndef _CRAY1 */
 478 #endif                          /* ndef vms */
 479
 480 /* For any platform where SCM_I_SETJMP hasn't been defined in some
 481    special way above, map SCM_I_SETJMP, SCM_I_LONGJMP and
 482    scm_i_jmp_buf to setjmp, longjmp and jmp_buf. */
 483 #ifndef SCM_I_SETJMP
 484 #define scm_i_jmp_buf jmp_buf
 485 #define SCM_I_SETJMP setjmp
 486 #define SCM_I_LONGJMP longjmp
 487 #endif
 488
 489 /* James Clark came up with this neat one instruction fix for
 490  * continuations on the SPARC.  It flushes the register windows so
 491  * that all the state of the process is contained in the stack.
 492  */
 493
 494 #if defined (sparc) || defined (__sparc__) || defined (__sparc)
 495 # define SCM_FLUSH_REGISTER_WINDOWS asm("ta 3")
 496 #else
 497 # define SCM_FLUSH_REGISTER_WINDOWS /* empty */
 498 #endif
 499
 500 /* If stack is not longword aligned then
 501  */
 502
 503 /* #define SHORT_ALIGN */
 504 #ifdef THINK_C
 505 # define SHORT_ALIGN
 506 #endif
 507 #ifdef MSDOS
 508 # define SHORT_ALIGN
 509 #endif
 510 #ifdef atarist
 511 # define SHORT_ALIGN
 512 #endif
 513
 514 #ifdef SHORT_ALIGN
 515 typedef short SCM_STACKITEM;
 516 #else
 517 typedef long SCM_STACKITEM;
 518 #endif
 519
 520 /* Cast pointer through (void *) in order to avoid compiler warnings
 521    when strict aliasing is enabled */
 522 #define SCM_STACK_PTR(ptr) ((SCM_STACKITEM *) (void *) (ptr))
 523 \f
 524
 525 SCM_API void scm_async_tick (void);
 526
 527 #ifdef BUILDING_LIBGUILE
 528
 529 /* FIXME: should change names */
 530 # define SCM_ASYNC_TICK                                                 \
 531     do                                                                  \
 532       {                                                                 \
 533         if (SCM_UNLIKELY (SCM_I_CURRENT_THREAD->pending_asyncs))        \
 534           scm_async_click ();                                           \
 535       }                                                                 \
 536     while (0)
 537
 538 /* SCM_ASYNC_TICK_WITH_CODE is only available to Guile itself */
 539 # define SCM_ASYNC_TICK_WITH_CODE(thr, stmt)                            \
 540     do                                                                  \
 541       {                                                                 \
 542         if (SCM_UNLIKELY (thr->pending_asyncs))                         \
 543           {                                                             \
 544             stmt;                                                       \
 545             scm_async_click ();                                         \
 546           }                                                             \
 547       }                                                                 \
 548     while (0)
 549
 550 #else /* !BUILDING_LIBGUILE */
 551
 552 # define SCM_ASYNC_TICK  (scm_async_tick ())
 553
 554 #endif /* !BUILDING_LIBGUILE */
 555
 556
 557 /* Anthony Green writes:
 558    When the compiler sees...
 559            DEFER_INTS;
 560            [critical code here]
 561            ALLOW_INTS;
 562    ...it doesn't actually promise to keep the critical code within the
 563    boundries of the DEFER/ALLOW_INTS instructions. It may very well
 564    schedule it outside of the magic defined in those macros.
 565
 566    However, GCC's volatile asm feature forms a barrier over which code is
 567    never moved. So if you add...
 568            asm ("");
 569    ...to each of the DEFER_INTS and ALLOW_INTS macros, the critical
 570    code will always remain in place.  asm's without inputs or outputs
 571    are implicitly volatile. */
 572 #ifdef __GNUC__
 573 #define SCM_FENCE asm /* volatile */ ("")
 574 #elif defined (__INTEL_COMPILER) && defined (__ia64)
 575 #define SCM_FENCE __memory_barrier()
 576 #else
 577 #define SCM_FENCE
 578 #endif
 579
 580 #define SCM_TICK \
 581 do { \
 582   SCM_ASYNC_TICK; \
 583   SCM_THREAD_SWITCHING_CODE; \
 584 } while (0)
 585
 586 \f
 587
 588 /** SCM_ASSERT
 589  **
 590  **/
 591
 592
 593 #ifdef SCM_RECKLESS
 594 #define SCM_ASSERT(_cond, _arg, _pos, _subr)
 595 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg)
 596 #define SCM_ASRTGO(_cond, _label)
 597 #else
 598 #define SCM_ASSERT(_cond, _arg, _pos, _subr)                    \
 599         do { if (SCM_UNLIKELY (!(_cond)))                       \
 600           scm_wrong_type_arg (_subr, _pos, _arg); } while (0)
 601 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg)                 \
 602         do { if (SCM_UNLIKELY (!(_cond)))                               \
 603           scm_wrong_type_arg_msg(_subr, _pos, _arg, _msg);  } while (0)
 604 #define SCM_ASRTGO(_cond, _label)               \
 605         do {  if (SCM_UNLIKELY (!(_cond)))      \
 606           goto _label; } while (0)
 607 #endif
 608
 609 /*
 610  * SCM_WTA_DISPATCH
 611  */
 612
 613 /* Dirk:FIXME:: In all of the SCM_WTA_DISPATCH_* macros it is assumed that
 614  * 'gf' is zero if uninitialized.  It would be cleaner if some valid SCM value
 615  * like SCM_BOOL_F or SCM_UNDEFINED was chosen.
 616  */
 617
 618 SCM_API SCM scm_call_generic_0 (SCM gf);
 619
 620 #define SCM_WTA_DISPATCH_0(gf, subr)                            \
 621   return (SCM_UNPACK (gf)                                       \
 622           ? scm_call_generic_0 ((gf))                           \
 623           : (scm_error_num_args_subr ((subr)), SCM_UNSPECIFIED))
 624 #define SCM_GASSERT0(cond, gf, subr)            \
 625   if (SCM_UNLIKELY(!(cond)))            \
 626     SCM_WTA_DISPATCH_0((gf), (subr))
 627
 628 SCM_API SCM scm_call_generic_1 (SCM gf, SCM a1);
 629
 630 #define SCM_WTA_DISPATCH_1(gf, a1, pos, subr)                   \
 631   return (SCM_UNPACK (gf)                                       \
 632           ? scm_call_generic_1 ((gf), (a1))                     \
 633           : (scm_wrong_type_arg ((subr), (pos), (a1)), SCM_UNSPECIFIED))
 634
 635 /* This form is for dispatching a subroutine.  */
 636 #define SCM_WTA_DISPATCH_1_SUBR(subr, a1, pos)                          \
 637   return (SCM_UNPACK ((*SCM_SUBR_GENERIC (subr)))                       \
 638           ? scm_call_generic_1 ((*SCM_SUBR_GENERIC (subr)), (a1))       \
 639           : (scm_i_wrong_type_arg_symbol (SCM_SUBR_NAME (subr), (pos), (a1)), SCM_UNSPECIFIED))
 640
 641 #define SCM_GASSERT1(cond, gf, a1, pos, subr)           \
 642   if (SCM_UNLIKELY (!(cond)))                   \
 643     SCM_WTA_DISPATCH_1((gf), (a1), (pos), (subr))
 644
 645 SCM_API SCM scm_call_generic_2 (SCM gf, SCM a1, SCM a2);
 646
 647 #define SCM_WTA_DISPATCH_2(gf, a1, a2, pos, subr)                       \
 648   return (SCM_UNPACK (gf)                                               \
 649           ? scm_call_generic_2 ((gf), (a1), (a2))                       \
 650           : (scm_wrong_type_arg ((subr), (pos),                         \
 651                                  (pos) == SCM_ARG1 ? (a1) : (a2)),      \
 652              SCM_UNSPECIFIED))
 653 #define SCM_GASSERT2(cond, gf, a1, a2, pos, subr)       \
 654   if (SCM_UNLIKELY (!(cond)))                   \
 655     SCM_WTA_DISPATCH_2((gf), (a1), (a2), (pos), (subr))
 656
 657 SCM_API SCM scm_apply_generic (SCM gf, SCM args);
 658
 659 #define SCM_WTA_DISPATCH_n(gf, args, pos, subr)                           \
 660   return (SCM_UNPACK (gf)                                                 \
 661           ? scm_apply_generic ((gf), (args))                              \
 662           : (scm_wrong_type_arg ((subr), (pos),                           \
 663                                  scm_list_ref ((args),                    \
 664                                                scm_from_int ((pos) - 1))), \
 665              SCM_UNSPECIFIED))
 666 #define SCM_GASSERTn(cond, gf, args, pos, subr)         \
 667   if (SCM_UNLIKELY (!(cond)))                   \
 668     SCM_WTA_DISPATCH_n((gf), (args), (pos), (subr))
 669
 670 #ifndef SCM_MAGIC_SNARFER
 671 /* Let these macros pass through if
 672    we are snarfing;  thus we can tell the
 673    difference between the use of an actual
 674    number vs. the use of one of these macros --
 675    actual numbers in SCM_VALIDATE_* and SCM_ASSERT
 676    constructs must match the formal argument name,
 677    but using SCM_ARG* avoids the test */
 678
 679 #define SCM_ARGn                0
 680 #define SCM_ARG1                1
 681 #define SCM_ARG2                2
 682 #define SCM_ARG3                3
 683 #define SCM_ARG4                4
 684 #define SCM_ARG5                5
 685 #define SCM_ARG6                6
 686 #define SCM_ARG7                7
 687
 688 #endif /* SCM_MAGIC_SNARFER */
 689
 690 \f
 691
 692 /* SCM_EXIT_SUCCESS is the default code to return from SCM if no errors
 693  * were encountered.  SCM_EXIT_FAILURE is the default code to return from
 694  * SCM if errors were encountered.  The return code can be explicitly
 695  * specified in a SCM program with (scm_quit <n>).
 696  */
 697
 698 #ifndef SCM_EXIT_SUCCESS
 699 #ifdef vms
 700 #define SCM_EXIT_SUCCESS 1
 701 #else
 702 #define SCM_EXIT_SUCCESS 0
 703 #endif /* def vms */
 704 #endif /* ndef SCM_EXIT_SUCCESS */
 705 #ifndef SCM_EXIT_FAILURE
 706 #ifdef vms
 707 #define SCM_EXIT_FAILURE 2
 708 #else
 709 #define SCM_EXIT_FAILURE 1
 710 #endif /* def vms */
 711 #endif /* ndef SCM_EXIT_FAILURE */
 712
 713 /* Define SCM_C_INLINE_KEYWORD so that it can be used as a replacement
 714    for the "inline" keyword, expanding to nothing when "inline" is not
 715    available.
 716 */
 717
 718 #ifdef SCM_C_INLINE
 719 #define SCM_C_INLINE_KEYWORD SCM_C_INLINE
 720 #else
 721 #define SCM_C_INLINE_KEYWORD
 722 #endif
 723
 724 /* Handling thread-local storage (TLS).  */
 725
 726 #ifdef SCM_HAVE_THREAD_STORAGE_CLASS
 727 # define SCM_THREAD_LOCAL __thread
 728 #else
 729 # define SCM_THREAD_LOCAL
 730 #endif
 731
 732 #endif  /* SCM___SCM_H */
 733
 734 /*
 735   Local Variables:
 736   c-file-style: "gnu"
 737   End:
 738 */