* __scm.h (SCM_STACK_PTR): New macro. (Cast argument through
[bpt/guile.git] / 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 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 /* If SCM_DEBUG_DEBUGGER_SUPPORT is set to 1, guile will provide a set of
260 * special functions that support debugging with a debugger like gdb. The
261 * behaviour of guile is not changed by this macro, only the set of functions
262 * that are available will differ. All functions that are introduced this way
263 * have the prefix 'scm_dbg_'. This allows to easily determine the set of
264 * support functions, given that your debugger provides automatic name
265 * completion. Note that these functions are intended to be used during
266 * interactive debugging sessions only. They are not considered part of
267 * guile's official API. They may change or disappear without notice or
268 * deprecation phase.
269 */
270 #ifndef SCM_DEBUG_DEBUGGER_SUPPORT
271 #define SCM_DEBUG_DEBUGGER_SUPPORT SCM_DEBUG
272 #endif
273
274 \f
275
276 /* {Feature Options}
277 *
278 * These compile time options determine whether code for certain features
279 * should be compiled into guile. The common prefix for all option macros
280 * of this kind is "SCM_ENABLE_". It is guaranteed that a macro named
281 * SCM_ENABLE_XXX is defined to be either 0 or 1, i. e. there is no need to
282 * test for the undefined case. This allows to use these definitions
283 * comfortably within code, as in the following example:
284 * #define FOO do { if (SCM_ENABLE_XXX) bar(); else baz(); } while (0)
285 * Any sane compiler will remove the unused branch without any performance
286 * penalty for the resulting code.
287 *
288 * Note: Some SCM_ENABLE_XXX options are not settable at configure time.
289 * To change the value of such options you will have to edit this header
290 * file or give suitable options to make, like:
291 * make all CFLAGS="-DSCM_ENABLE_XXX=1 ..."
292 */
293
294 /* If SCM_ENABLE_DEPRECATED is set to 1, deprecated code will be included in
295 * guile, as well as some functions to issue run-time warnings about uses of
296 * deprecated functions.
297 */
298 #ifndef SCM_ENABLE_DEPRECATED
299 #define SCM_ENABLE_DEPRECATED 0
300 #endif
301
302 \f
303
304 /* {Architecture and compiler properties}
305 *
306 * Guile as of today can only work on systems which fulfill at least the
307 * following requirements:
308 * - long ints have at least 32 bits.
309 * Guile's type system is based on this assumption.
310 * - long ints consist of at least four characters.
311 * It is assumed that cells, i. e. pairs of long ints, are eight character
312 * aligned, because three bits of a cell pointer are used for type data.
313 * - sizeof (void*) == sizeof (long int)
314 * Pointers are stored in SCM objects, and sometimes SCM objects are passed
315 * as void*. Thus, there has to be a one-to-one correspondence.
316 * - numbers are encoded using two's complement.
317 * The implementation of the bitwise scheme level operations is based on
318 * this assumption.
319 * - ... add more
320 */
321
322 #ifdef CHAR_BIT
323 # define SCM_CHAR_BIT CHAR_BIT
324 #else
325 # define SCM_CHAR_BIT 8
326 #endif
327
328 #ifdef LONG_BIT
329 # define SCM_LONG_BIT LONG_BIT
330 #else
331 # define SCM_LONG_BIT (SCM_CHAR_BIT * sizeof (long) / sizeof (char))
332 #endif
333
334 #ifdef UCHAR_MAX
335 # define SCM_CHAR_CODE_LIMIT (UCHAR_MAX + 1L)
336 #else
337 # define SCM_CHAR_CODE_LIMIT 256L
338 #endif
339
340 \f
341
342 #include "libguile/tags.h"
343
344 \f
345 #ifdef vms
346 # ifndef CHEAP_CONTINUATIONS
347 typedef int jmp_buf[17];
348 extern int setjump(jmp_buf env);
349 extern int longjump(jmp_buf env, int ret);
350 # define setjmp setjump
351 # define longjmp longjump
352 # else
353 # include <setjmp.h>
354 # endif
355 #else /* ndef vms */
356 # ifdef _CRAY1
357 typedef int jmp_buf[112];
358 extern int setjump(jmp_buf env);
359 extern int longjump(jmp_buf env, int ret);
360 # define setjmp setjump
361 # define longjmp longjump
362 # else /* ndef _CRAY1 */
363 # include <setjmp.h>
364 # endif /* ndef _CRAY1 */
365 #endif /* ndef vms */
366
367 /* James Clark came up with this neat one instruction fix for
368 * continuations on the SPARC. It flushes the register windows so
369 * that all the state of the process is contained in the stack.
370 */
371
372 #if defined (sparc) || defined (__sparc__) || defined (__sparc)
373 # define SCM_FLUSH_REGISTER_WINDOWS asm("ta 3")
374 #else
375 # define SCM_FLUSH_REGISTER_WINDOWS /* empty */
376 #endif
377
378 /* If stack is not longword aligned then
379 */
380
381 /* #define SHORT_ALIGN */
382 #ifdef THINK_C
383 # define SHORT_ALIGN
384 #endif
385 #ifdef MSDOS
386 # define SHORT_ALIGN
387 #endif
388 #ifdef atarist
389 # define SHORT_ALIGN
390 #endif
391
392 #ifdef SHORT_ALIGN
393 typedef short SCM_STACKITEM;
394 #else
395 typedef long SCM_STACKITEM;
396 #endif
397
398 /* Cast pointer through (void *) in order to avoid compiler warnings
399 when strict aliasing is enabled */
400 #define SCM_STACK_PTR(ptr) ((SCM_STACKITEM *) (void *) (ptr))
401 \f
402
403 #define SCM_ASYNC_TICK /*fixme* should change names */ \
404 do { \
405 if (scm_root->pending_asyncs) \
406 scm_async_click (); \
407 } while (0)
408
409
410 /* Anthony Green writes:
411 When the compiler sees...
412 DEFER_INTS;
413 [critical code here]
414 ALLOW_INTS;
415 ...it doesn't actually promise to keep the critical code within the
416 boundries of the DEFER/ALLOW_INTS instructions. It may very well
417 schedule it outside of the magic defined in those macros.
418
419 However, GCC's volatile asm feature forms a barrier over which code is
420 never moved. So if you add...
421 asm ("");
422 ...to each of the DEFER_INTS and ALLOW_INTS macros, the critical
423 code will always remain in place. asm's without inputs or outputs
424 are implicitly volatile. */
425 #ifdef __GNUC__
426 #define SCM_FENCE asm /* volatile */ ("")
427 #else
428 #define SCM_FENCE
429 #endif
430
431 #define SCM_DEFER_INTS scm_rec_mutex_lock (&scm_i_defer_mutex);
432
433 #define SCM_ALLOW_INTS scm_rec_mutex_unlock (&scm_i_defer_mutex);
434
435 #define SCM_REDEFER_INTS SCM_DEFER_INTS
436
437 #define SCM_REALLOW_INTS SCM_ALLOW_INTS
438
439 #define SCM_TICK \
440 do { \
441 SCM_ASYNC_TICK; \
442 SCM_THREAD_SWITCHING_CODE; \
443 } while (0)
444
445 \f
446
447 /* Note: The following needs updating. */
448
449 /* Classification of critical sections
450 *
451 * When Guile moves to POSIX threads, it won't be possible to prevent
452 * context switching. In fact, the whole idea of context switching is
453 * bogus if threads are run by different processors. Therefore, we
454 * must ultimately eliminate all critical sections or enforce them by
455 * use of mutecis.
456 *
457 * All instances of SCM_DEFER_INTS and SCM_ALLOW_INTS should therefore
458 * be classified and replaced by one of the delimiters below. If you
459 * understand what this is all about, I'd like to encourage you to
460 * help with this task. The set of classes below must of course be
461 * incrementally augmented.
462 *
463 * MDJ 980419 <djurfeldt@nada.kth.se>
464 */
465
466 /* A sections
467 *
468 * Allocation of a cell with type tag in the CAR.
469 *
470 * With POSIX threads, each thread will have a private pool of free
471 * cells. Therefore, this type of section can be removed. But! It
472 * is important that the CDR is initialized first (with the CAR still
473 * indicating a free cell) so that we can guarantee a consistent heap
474 * at all times.
475 */
476
477 #define SCM_ENTER_A_SECTION SCM_CRITICAL_SECTION_START
478 #define SCM_EXIT_A_SECTION SCM_CRITICAL_SECTION_END
479
480 \f
481
482 /** SCM_ASSERT
483 **
484 **/
485
486
487 #ifdef SCM_RECKLESS
488 #define SCM_ASSERT(_cond, _arg, _pos, _subr)
489 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg)
490 #define SCM_ASRTGO(_cond, _label)
491 #else
492 #define SCM_ASSERT(_cond, _arg, _pos, _subr) \
493 if (!(_cond)) \
494 scm_wrong_type_arg (_subr, _pos, _arg)
495 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg) \
496 if (!(_cond)) \
497 scm_wrong_type_arg_msg(_subr, _pos, _arg, _msg)
498 #define SCM_ASRTGO(_cond, _label) \
499 if (!(_cond)) \
500 goto _label
501 #endif
502
503 /*
504 * SCM_WTA_DISPATCH
505 */
506
507 /* Dirk:FIXME:: In all of the SCM_WTA_DISPATCH_* macros it is assumed that
508 * 'gf' is zero if uninitialized. It would be cleaner if some valid SCM value
509 * like SCM_BOOL_F or SCM_UNDEFINED was chosen.
510 */
511
512 SCM_API SCM scm_call_generic_0 (SCM gf);
513
514 #define SCM_WTA_DISPATCH_0(gf, subr) \
515 return (SCM_UNPACK (gf) \
516 ? scm_call_generic_0 ((gf)) \
517 : (scm_error_num_args_subr ((subr)), SCM_UNSPECIFIED))
518 #define SCM_GASSERT0(cond, gf, subr) \
519 if (!(cond)) SCM_WTA_DISPATCH_0((gf), (subr))
520
521 SCM_API SCM scm_call_generic_1 (SCM gf, SCM a1);
522
523 #define SCM_WTA_DISPATCH_1(gf, a1, pos, subr) \
524 return (SCM_UNPACK (gf) \
525 ? scm_call_generic_1 ((gf), (a1)) \
526 : (scm_wrong_type_arg ((subr), (pos), (a1)), SCM_UNSPECIFIED))
527 #define SCM_GASSERT1(cond, gf, a1, pos, subr) \
528 if (!(cond)) SCM_WTA_DISPATCH_1((gf), (a1), (pos), (subr))
529
530 SCM_API SCM scm_call_generic_2 (SCM gf, SCM a1, SCM a2);
531
532 #define SCM_WTA_DISPATCH_2(gf, a1, a2, pos, subr) \
533 return (SCM_UNPACK (gf) \
534 ? scm_call_generic_2 ((gf), (a1), (a2)) \
535 : (scm_wrong_type_arg ((subr), (pos), \
536 (pos) == SCM_ARG1 ? (a1) : (a2)), \
537 SCM_UNSPECIFIED))
538 #define SCM_GASSERT2(cond, gf, a1, a2, pos, subr) \
539 if (!(cond)) SCM_WTA_DISPATCH_2((gf), (a1), (a2), (pos), (subr))
540
541 SCM_API SCM scm_apply_generic (SCM gf, SCM args);
542
543 #define SCM_WTA_DISPATCH_n(gf, args, pos, subr) \
544 return (SCM_UNPACK (gf) \
545 ? scm_apply_generic ((gf), (args)) \
546 : (scm_wrong_type_arg ((subr), (pos), \
547 scm_list_ref ((args), \
548 SCM_MAKINUM ((pos) - 1))), \
549 SCM_UNSPECIFIED))
550 #define SCM_GASSERTn(cond, gf, args, pos, subr) \
551 if (!(cond)) SCM_WTA_DISPATCH_n((gf), (args), (pos), (subr))
552
553 #ifndef SCM_MAGIC_SNARFER
554 /* Let these macros pass through if
555 we are snarfing; thus we can tell the
556 difference between the use of an actual
557 number vs. the use of one of these macros --
558 actual numbers in SCM_VALIDATE_* and SCM_ASSERT
559 constructs must match the formal argument name,
560 but using SCM_ARG* avoids the test */
561
562 #define SCM_ARGn 0
563 #define SCM_ARG1 1
564 #define SCM_ARG2 2
565 #define SCM_ARG3 3
566 #define SCM_ARG4 4
567 #define SCM_ARG5 5
568 #define SCM_ARG6 6
569 #define SCM_ARG7 7
570
571 #endif /* SCM_MAGIC_SNARFER */
572
573 \f
574
575 /* SCM_EXIT_SUCCESS is the default code to return from SCM if no errors
576 * were encountered. SCM_EXIT_FAILURE is the default code to return from
577 * SCM if errors were encountered. The return code can be explicitly
578 * specified in a SCM program with (scm_quit <n>).
579 */
580
581 #ifndef SCM_EXIT_SUCCESS
582 #ifdef vms
583 #define SCM_EXIT_SUCCESS 1
584 #else
585 #define SCM_EXIT_SUCCESS 0
586 #endif /* def vms */
587 #endif /* ndef SCM_EXIT_SUCCESS */
588 #ifndef SCM_EXIT_FAILURE
589 #ifdef vms
590 #define SCM_EXIT_FAILURE 2
591 #else
592 #define SCM_EXIT_FAILURE 1
593 #endif /* def vms */
594 #endif /* ndef SCM_EXIT_FAILURE */
595
596 #endif /* SCM___SCM_H */
597
598 /*
599 Local Variables:
600 c-file-style: "gnu"
601 End:
602 */