revert the ill-considered part of the 2001-05-24 changes
[bpt/guile.git] / libguile / __scm.h
1 /* classes: h_files */
2
3 #ifndef __SCMH
4 #define __SCMH
5 /* Copyright (C) 1995,1996,1998,1999,2000,2001 Free Software Foundation, Inc.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2, or (at your option)
10 * any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this software; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
20 * Boston, MA 02111-1307 USA
21 *
22 * As a special exception, the Free Software Foundation gives permission
23 * for additional uses of the text contained in its release of GUILE.
24 *
25 * The exception is that, if you link the GUILE library with other files
26 * to produce an executable, this does not by itself cause the
27 * resulting executable to be covered by the GNU General Public License.
28 * Your use of that executable is in no way restricted on account of
29 * linking the GUILE library code into it.
30 *
31 * This exception does not however invalidate any other reasons why
32 * the executable file might be covered by the GNU General Public License.
33 *
34 * This exception applies only to the code released by the
35 * Free Software Foundation under the name GUILE. If you copy
36 * code from other Free Software Foundation releases into a copy of
37 * GUILE, as the General Public License permits, the exception does
38 * not apply to the code that you add in this way. To avoid misleading
39 * anyone as to the status of such modified files, you must delete
40 * this exception notice from them.
41 *
42 * If you write modifications of your own for GUILE, it is your choice
43 * whether to permit this exception to apply to your modifications.
44 * If you do not wish that, delete this exception notice. */
45 \f
46
47 /* "What's the difference between _scm.h and __scm.h?"
48
49 _scm.h is not installed; it's only visible to the libguile sources
50 themselves.
51
52 __scm.h is installed, and is #included by <libguile.h>. If both
53 the client and libguile need some piece of information, and it
54 doesn't fit well into the header file for any particular module, it
55 should go in __scm.h. */
56
57
58 /* {Supported Options}
59 *
60 * These may be defined or undefined.
61 */
62
63 /* Old async mechanism */
64 /* #define GUILE_OLD_ASYNC_CLICK */
65
66 /* #define GUILE_DEBUG_FREELIST */
67
68 /* If the compile FLAG `SCM_CAUTIOUS' is #defined then the number of
69 * arguments is always checked for application of closures. If the
70 * compile FLAG `SCM_RECKLESS' is #defined then they are not checked.
71 * Otherwise, number of argument checks for closures are made only when
72 * the function position (whose value is the closure) of a combination is
73 * not an ILOC or GLOC. When the function position of a combination is a
74 * symbol it will be checked only the first time it is evaluated because
75 * it will then be replaced with an ILOC or GLOC.
76 */
77 #undef SCM_RECKLESS
78 #define SCM_CAUTIOUS
79
80 /* After looking up a local for the first time, rewrite the
81 * code graph, caching its position.
82 */
83 #define MEMOIZE_LOCALS
84
85 /* All the number support there is.
86 */
87 #define BIGNUMS
88
89 /* GC should relinquish empty cons-pair arenas. */
90 /* cmm:FIXME look at this after done mangling the GC */
91 /* #define GC_FREE_SEGMENTS */
92
93 /* Provide a scheme-accessible count-down timer that
94 * generates a pseudo-interrupt.
95 */
96 #define TICKS
97
98
99 /* Use engineering notation when converting numbers strings?
100 */
101 #undef ENGNOT
102
103 \f
104 /* {Unsupported Options}
105 *
106 * These must be defined as given here.
107 */
108
109
110 #define CCLO
111
112 /* Guile Scheme supports the #f/() distinction; Guile Lisp won't. We
113 have horrible plans for their unification. */
114 #undef SICP
115
116 \f
117
118 /* Random options (not yet supported or in final form). */
119
120 #define STACK_CHECKING
121 #undef NO_CEVAL_STACK_CHECKING
122
123 \f
124
125 /* What did the configure script discover about the outside world? */
126 #include "libguile/scmconfig.h"
127
128 \f
129
130 /* {Debugging Options}
131 *
132 * These compile time options determine whether to include code that is only
133 * useful for debugging guile itself or C level extensions to guile. The
134 * common prefix for all option macros of this kind is "SCM_DEBUG_". It is
135 * guaranteed that a macro named SCM_DEBUG_XXX is defined to be either 0 or 1,
136 * i. e. there is no need to test for the undefined case. This allows to use
137 * these definitions comfortably in macro code, as in the following example:
138 * #define FOO do { if (SCM_DEBUG_XXX) bar(); else baz(); } while (0)
139 * Any sane compiler will remove the unused branch without any performance
140 * penalty for the resulting code.
141 *
142 * Note: Some SCM_DEBUG_XXX options are not settable at configure time.
143 * To change the value of such options you will have to edit this header
144 * file or give suitable options to make, like:
145 * make all CFLAGS="-DSCM_DEBUG_XXX=1 ..."
146 */
147
148
149 /* The value of SCM_DEBUG determines the default for most of the not yet
150 * defined debugging options. This allows, for example, to enable most of the
151 * debugging options by simply defining SCM_DEBUG as 1.
152 */
153 #ifndef SCM_DEBUG
154 #define SCM_DEBUG 0
155 #endif
156
157 /* If SCM_DEBUG_CELL_ACCESSES is set to 1, cell accesses will perform
158 * exhaustive parameter checking: It will be verified that cell parameters
159 * actually point to a valid heap cell. Note: If this option is enabled,
160 * guile will run about ten times slower than normally.
161 */
162 #ifndef SCM_DEBUG_CELL_ACCESSES
163 #define SCM_DEBUG_CELL_ACCESSES SCM_DEBUG
164 #endif
165
166 /* If SCM_DEBUG_DEPRECATED is set to 1, deprecated code is not compiled. This
167 * can be used by developers to get rid of references to deprecated code.
168 */
169 #ifndef SCM_DEBUG_DEPRECATED
170 #define SCM_DEBUG_DEPRECATED SCM_DEBUG
171 #endif
172
173 /* If SCM_DEBUG_INTERRUPTS is set to 1, with every deferring and allowing of
174 * interrupts a consistency check will be performed.
175 */
176 #ifndef SCM_DEBUG_INTERRUPTS
177 #define SCM_DEBUG_INTERRUPTS SCM_DEBUG
178 #endif
179
180 /* If SCM_DEBUG_REST_ARGUMENT is set to 1, functions that take rest arguments
181 * will check whether the rest arguments are actually passed as a proper list.
182 * Otherwise, if SCM_DEBUG_REST_ARGUMENT is 0, functions that take rest
183 * arguments will take it for granted that these are passed as a proper list.
184 */
185 #ifndef SCM_DEBUG_REST_ARGUMENT
186 #define SCM_DEBUG_REST_ARGUMENT SCM_DEBUG
187 #endif
188
189 /* Use this for _compile time_ type checking only, since the compiled result
190 * will be quite inefficient. The right way to make use of this option is to
191 * do a 'make clean; make CFLAGS=-DSCM_DEBUG_TYPING_STRICTNESS=1', fix your
192 * errors, and then do 'make clean; make'.
193 */
194 #ifndef SCM_DEBUG_TYPING_STRICTNESS
195 #define SCM_DEBUG_TYPING_STRICTNESS 0
196 #endif
197
198 /* If SCM_ENABLE_VCELLS is set to 1, a couple of functions that deal
199 * with vcells are defined for compatability reasons. Supporting
200 * vcells reduces performance however.
201 *
202 * We use a dedicated macro instead of just SCM_DEBUG_DEPRECATED so
203 * that code the belongs to the `vcell' feature is easier to find.
204 */
205 #define SCM_ENABLE_VCELLS !SCM_DEBUG_DEPRECATED
206
207 \f
208
209 #ifdef HAVE_LONG_LONGS
210
211 /* Some auto-generated .h files contain unused prototypes
212 * that need these typedefs.
213 */
214
215 #if (SCM_DEBUG_DEPRECATED == 0)
216 typedef long long long_long;
217 typedef unsigned long long ulong_long;
218 #endif
219
220 #endif /* HAVE_LONG_LONGS */
221
222 \f
223
224 /* {Architecture and compiler properties}
225 *
226 * Guile as of today can only work on systems which fulfill at least the
227 * following requirements:
228 * - long ints have at least 32 bits.
229 * Guile's type system is based on this assumption.
230 * - long ints consist of at least four characters.
231 * It is assumed that cells, i. e. pairs of long ints, are eight character
232 * aligned, because three bits of a cell pointer are used for type data.
233 * - sizeof (void*) == sizeof (long int)
234 * Pointers are stored in SCM objects, and sometimes SCM objects are passed
235 * as void*. Thus, there has to be a one-to-one correspondence.
236 * - numbers are encoded using two's complement.
237 * The implementation of the bitwise scheme level operations is based on
238 * this assumption.
239 * - ... add more
240 */
241
242 #ifdef HAVE_LIMITS_H
243 # include <limits.h>
244 #endif
245
246 #ifdef CHAR_BIT
247 # define SCM_CHAR_BIT CHAR_BIT
248 #else
249 # define SCM_CHAR_BIT 8
250 #endif
251
252 #ifdef LONG_BIT
253 # define SCM_LONG_BIT LONG_BIT
254 #else
255 # define SCM_LONG_BIT (SCM_CHAR_BIT * sizeof (long) / sizeof (char))
256 #endif
257
258 #ifdef UCHAR_MAX
259 # define SCM_CHAR_CODE_LIMIT (UCHAR_MAX + 1L)
260 #else
261 # define SCM_CHAR_CODE_LIMIT 256L
262 #endif
263
264 \f
265
266 #ifdef STDC_HEADERS
267 # include <stdlib.h>
268 # if HAVE_SYS_TYPES_H
269 # include <sys/types.h>
270 # endif
271 # if HAVE_SYS_STDTYPES_H
272 # include <sys/stdtypes.h>
273 # endif
274 # include <stddef.h>
275 #endif /* def STDC_HEADERS */
276
277 #if (SCM_DEBUG_DEPRECATED == 0)
278 # define scm_sizet size_t
279 #endif
280
281 \f
282
283 #include "libguile/tags.h"
284
285 \f
286 #ifdef vms
287 # ifndef CHEAP_CONTINUATIONS
288 typedef int jmp_buf[17];
289 extern int setjump(jmp_buf env);
290 extern int longjump(jmp_buf env, int ret);
291 # define setjmp setjump
292 # define longjmp longjump
293 # else
294 # include <setjmp.h>
295 # endif
296 #else /* ndef vms */
297 # ifdef _CRAY1
298 typedef int jmp_buf[112];
299 extern int setjump(jmp_buf env);
300 extern int longjump(jmp_buf env, int ret);
301 # define setjmp setjump
302 # define longjmp longjump
303 # else /* ndef _CRAY1 */
304 # include <setjmp.h>
305 # endif /* ndef _CRAY1 */
306 #endif /* ndef vms */
307
308 /* James Clark came up with this neat one instruction fix for
309 * continuations on the SPARC. It flushes the register windows so
310 * that all the state of the process is contained in the stack.
311 */
312
313 #ifdef sparc
314 # define SCM_FLUSH_REGISTER_WINDOWS asm("ta 3")
315 #else
316 # define SCM_FLUSH_REGISTER_WINDOWS /* empty */
317 #endif
318
319 /* If stack is not longword aligned then
320 */
321
322 /* #define SHORT_ALIGN */
323 #ifdef THINK_C
324 # define SHORT_ALIGN
325 #endif
326 #ifdef MSDOS
327 # define SHORT_ALIGN
328 #endif
329 #ifdef atarist
330 # define SHORT_ALIGN
331 #endif
332
333 #ifdef SHORT_ALIGN
334 typedef short SCM_STACKITEM;
335 #else
336 typedef long SCM_STACKITEM;
337 #endif
338 \f
339
340 #ifndef USE_THREADS
341 #define SCM_CRITICAL_SECTION_START
342 #define SCM_CRITICAL_SECTION_END
343 #define SCM_THREAD_SWITCHING_CODE
344 #endif
345
346 #ifdef GUILE_OLD_ASYNC_CLICK
347 extern unsigned int scm_async_clock;
348
349 #define SCM_ASYNC_TICK \
350 do { \
351 if (0 == --scm_async_clock) \
352 scm_async_click (); \
353 } while(0)
354 #else
355 extern int scm_asyncs_pending_p;
356
357 #define SCM_ASYNC_TICK /*fixme* should change names */ \
358 do { \
359 if (scm_asyncs_pending_p) \
360 scm_async_click (); \
361 } while (0)
362 #endif
363
364 #if (SCM_DEBUG_INTERRUPTS == 1)
365 #include <stdio.h>
366 #define SCM_CHECK_NOT_DISABLED \
367 do { \
368 if (scm_ints_disabled) \
369 fprintf(stderr, "ints already disabled (at %s:%d)\n", \
370 __FILE__, __LINE__); \
371 } while (0)
372
373 #define SCM_CHECK_NOT_ENABLED \
374 do { \
375 if (!scm_ints_disabled) \
376 fprintf(stderr, "ints already enabled (at %s:%d)\n", \
377 __FILE__, __LINE__); \
378 } while (0)
379
380 #else
381 #define SCM_CHECK_NOT_DISABLED
382 #define SCM_CHECK_NOT_ENABLED
383 #endif
384
385
386 /* Anthony Green writes:
387 When the compiler sees...
388 DEFER_INTS;
389 [critical code here]
390 ALLOW_INTS;
391 ...it doesn't actually promise to keep the critical code within the
392 boundries of the DEFER/ALLOW_INTS instructions. It may very well
393 schedule it outside of the magic defined in those macros.
394
395 However, GCC's volatile asm feature forms a barrier over which code is
396 never moved. So if you add...
397 asm ("");
398 ...to each of the DEFER_INTS and ALLOW_INTS macros, the critical
399 code will always remain in place. asm's without inputs or outputs
400 are implicitly volatile. */
401 #ifdef __GNUC__
402 #define SCM_FENCE asm /* volatile */ ("")
403 #else
404 #define SCM_FENCE
405 #endif
406
407 #define SCM_DEFER_INTS \
408 do { \
409 SCM_FENCE; \
410 SCM_CHECK_NOT_DISABLED; \
411 SCM_CRITICAL_SECTION_START; \
412 SCM_FENCE; \
413 scm_ints_disabled = 1; \
414 SCM_FENCE; \
415 } while (0)
416
417
418 #define SCM_ALLOW_INTS_ONLY \
419 do { \
420 SCM_CRITICAL_SECTION_END; \
421 scm_ints_disabled = 0; \
422 } while (0)
423
424
425 #define SCM_ALLOW_INTS \
426 do { \
427 SCM_FENCE; \
428 SCM_CHECK_NOT_ENABLED; \
429 SCM_CRITICAL_SECTION_END; \
430 SCM_FENCE; \
431 scm_ints_disabled = 0; \
432 SCM_FENCE; \
433 SCM_THREAD_SWITCHING_CODE; \
434 SCM_FENCE; \
435 } while (0)
436
437
438 #define SCM_REDEFER_INTS \
439 do { \
440 SCM_FENCE; \
441 SCM_CRITICAL_SECTION_START; \
442 ++scm_ints_disabled; \
443 SCM_FENCE; \
444 } while (0)
445
446
447 #define SCM_REALLOW_INTS \
448 do { \
449 SCM_FENCE; \
450 SCM_CRITICAL_SECTION_END; \
451 SCM_FENCE; \
452 --scm_ints_disabled; \
453 SCM_FENCE; \
454 } while (0)
455
456
457 #define SCM_TICK \
458 do { \
459 SCM_ASYNC_TICK; \
460 SCM_THREAD_SWITCHING_CODE; \
461 } while (0)
462
463 \f
464
465 /* Classification of critical sections
466 *
467 * When Guile moves to POSIX threads, it won't be possible to prevent
468 * context switching. In fact, the whole idea of context switching is
469 * bogus if threads are run by different processors. Therefore, we
470 * must ultimately eliminate all critical sections or enforce them by
471 * use of mutecis.
472 *
473 * All instances of SCM_DEFER_INTS and SCM_ALLOW_INTS should therefore
474 * be classified and replaced by one of the delimiters below. If you
475 * understand what this is all about, I'd like to encourage you to
476 * help with this task. The set of classes below must of course be
477 * incrementally augmented.
478 *
479 * MDJ 980419 <djurfeldt@nada.kth.se>
480 */
481
482 /* A sections
483 *
484 * Allocation of a cell with type tag in the CAR.
485 *
486 * With POSIX threads, each thread will have a private pool of free
487 * cells. Therefore, this type of section can be removed. But! It
488 * is important that the CDR is initialized first (with the CAR still
489 * indicating a free cell) so that we can guarantee a consistent heap
490 * at all times.
491 */
492
493 #define SCM_ENTER_A_SECTION SCM_CRITICAL_SECTION_START
494 #define SCM_EXIT_A_SECTION SCM_CRITICAL_SECTION_END
495
496 \f
497
498 /** SCM_ASSERT
499 **
500 **/
501
502
503 #ifdef SCM_RECKLESS
504 #define SCM_ASSERT(_cond, _arg, _pos, _subr)
505 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg)
506 #define SCM_ASRTGO(_cond, _label)
507 #else
508 #define SCM_ASSERT(_cond, _arg, _pos, _subr) \
509 if (!(_cond)) \
510 scm_wrong_type_arg (_subr, _pos, _arg)
511 #define SCM_ASSERT_TYPE(_cond, _arg, _pos, _subr, _msg) \
512 if (!(_cond)) \
513 scm_wrong_type_arg_msg(_subr, _pos, _arg, _msg)
514 #define SCM_ASRTGO(_cond, _label) \
515 if (!(_cond)) \
516 goto _label
517 #endif
518
519 /*
520 * SCM_WTA_DISPATCH
521 */
522
523 /* Dirk:FIXME:: In all of the SCM_WTA_DISPATCH_* macros it is assumed that
524 * 'gf' is zero if uninitialized. It would be cleaner if some valid SCM value
525 * like SCM_BOOL_F or SCM_UNDEFINED was chosen.
526 */
527
528 extern SCM scm_call_generic_0 (SCM gf);
529
530 #define SCM_WTA_DISPATCH_0(gf, subr) \
531 return (SCM_UNPACK (gf) \
532 ? scm_call_generic_0 ((gf)) \
533 : (scm_error_num_args_subr ((subr)), SCM_UNSPECIFIED))
534 #define SCM_GASSERT0(cond, gf, subr) \
535 if (!(cond)) SCM_WTA_DISPATCH_0((gf), (subr))
536
537 extern SCM scm_call_generic_1 (SCM gf, SCM a1);
538
539 #define SCM_WTA_DISPATCH_1(gf, a1, pos, subr) \
540 return (SCM_UNPACK (gf) \
541 ? scm_call_generic_1 ((gf), (a1)) \
542 : (scm_wrong_type_arg ((subr), (pos), (a1)), SCM_UNSPECIFIED))
543 #define SCM_GASSERT1(cond, gf, a1, pos, subr) \
544 if (!(cond)) SCM_WTA_DISPATCH_1((gf), (a1), (pos), (subr))
545
546 extern SCM scm_call_generic_2 (SCM gf, SCM a1, SCM a2);
547
548 #define SCM_WTA_DISPATCH_2(gf, a1, a2, pos, subr) \
549 return (SCM_UNPACK (gf) \
550 ? scm_call_generic_2 ((gf), (a1), (a2)) \
551 : (scm_wrong_type_arg ((subr), (pos), \
552 (pos) == SCM_ARG1 ? (a1) : (a2)), \
553 SCM_UNSPECIFIED))
554 #define SCM_GASSERT2(cond, gf, a1, a2, pos, subr) \
555 if (!(cond)) SCM_WTA_DISPATCH_2((gf), (a1), (a2), (pos), (subr))
556
557 extern SCM scm_apply_generic (SCM gf, SCM args);
558
559 #define SCM_WTA_DISPATCH_n(gf, args, pos, subr) \
560 return (SCM_UNPACK (gf) \
561 ? scm_apply_generic ((gf), (args)) \
562 : (scm_wrong_type_arg ((subr), (pos), \
563 scm_list_ref ((args), \
564 SCM_MAKINUM ((pos) - 1))), \
565 SCM_UNSPECIFIED))
566 #define SCM_GASSERTn(cond, gf, args, pos, subr) \
567 if (!(cond)) SCM_WTA_DISPATCH_n((gf), (args), (pos), (subr))
568
569 #ifndef SCM_MAGIC_SNARFER
570 /* Let these macros pass through if
571 we are snarfing; thus we can tell the
572 difference between the use of an actual
573 number vs. the use of one of these macros --
574 actual numbers in SCM_VALIDATE_* and SCM_ASSERT
575 constructs must match the formal argument name,
576 but using SCM_ARG* avoids the test */
577
578 #define SCM_ARGn 0
579 #define SCM_ARG1 1
580 #define SCM_ARG2 2
581 #define SCM_ARG3 3
582 #define SCM_ARG4 4
583 #define SCM_ARG5 5
584 #define SCM_ARG6 6
585 #define SCM_ARG7 7
586
587 #if (SCM_DEBUG_DEPRECATED == 0)
588
589 /* Use SCM_WRONG_NUM_ARGS instead of: */
590 #define SCM_WNA 8
591
592 /* Use SCM_ASSERT_RANGE or SCM_VALIDATE_XXX_RANGE instead of: */
593 #define SCM_OUTOFRANGE 10
594
595 /* Use scm_memory_error instead of: */
596 #define SCM_NALLOC 11
597
598 #define SCM_HUP_SIGNAL 14
599 #define SCM_INT_SIGNAL 15
600 #define SCM_FPE_SIGNAL 16
601 #define SCM_BUS_SIGNAL 17
602 #define SCM_SEGV_SIGNAL 18
603 #define SCM_ALRM_SIGNAL 19
604 #define SCM_GC_SIGNAL 20
605 #define SCM_TICK_SIGNAL 21
606 #define SCM_SIG_ORD(X) ((X) - SCM_HUP_SIGNAL)
607 #define SCM_ORD_SIG(X) ((X) + SCM_HUP_SIGNAL)
608 #define SCM_NUM_SIGS (SCM_SIG_ORD (SCM_TICK_SIGNAL) + 1)
609
610 #endif /* SCM_DEBUG_DEPRECATED == 0 */
611
612 #endif /* SCM_MAGIC_SNARFER */
613
614 \f
615
616 /* SCM_EXIT_SUCCESS is the default code to return from SCM if no errors
617 * were encountered. SCM_EXIT_FAILURE is the default code to return from
618 * SCM if errors were encountered. The return code can be explicitly
619 * specified in a SCM program with (scm_quit <n>).
620 */
621
622 #ifndef SCM_EXIT_SUCCESS
623 #ifdef vms
624 #define SCM_EXIT_SUCCESS 1
625 #else
626 #define SCM_EXIT_SUCCESS 0
627 #endif /* def vms */
628 #endif /* ndef SCM_EXIT_SUCCESS */
629 #ifndef SCM_EXIT_FAILURE
630 #ifdef vms
631 #define SCM_EXIT_FAILURE 2
632 #else
633 #define SCM_EXIT_FAILURE 1
634 #endif /* def vms */
635 #endif /* ndef SCM_EXIT_FAILURE */
636
637 \f
638
639 #endif /* __SCMH */
640
641 /*
642 Local Variables:
643 c-file-style: "gnu"
644 End:
645 */