Commit | Line | Data |
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c2247b78 | 1 | /* Copyright (C) 1995,1996,1998,2000,2001,2004, 2006, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Free Software Foundation, Inc. |
0f2d19dd | 2 | * |
73be1d9e | 3 | * This library is free software; you can redistribute it and/or |
53befeb7 NJ |
4 | * modify it under the terms of the GNU Lesser General Public License |
5 | * as published by the Free Software Foundation; either version 3 of | |
6 | * the License, or (at your option) any later version. | |
0f2d19dd | 7 | * |
53befeb7 NJ |
8 | * This library is distributed in the hope that it will be useful, but |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
73be1d9e MV |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
11 | * Lesser General Public License for more details. | |
0f2d19dd | 12 | * |
73be1d9e MV |
13 | * You should have received a copy of the GNU Lesser General Public |
14 | * License along with this library; if not, write to the Free Software | |
53befeb7 NJ |
15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
16 | * 02110-1301 USA | |
73be1d9e | 17 | */ |
1bbd0b84 | 18 | |
1bbd0b84 | 19 | |
0f2d19dd | 20 | \f |
dbb605f5 LC |
21 | #ifdef HAVE_CONFIG_H |
22 | # include <config.h> | |
23 | #endif | |
0f2d19dd | 24 | |
bbd43f03 RB |
25 | #include "libguile/_scm.h" |
26 | ||
9ede013f | 27 | #include <assert.h> |
13070bd3 | 28 | #include <string.h> |
8b7f0bb3 | 29 | #include <stdio.h> |
13070bd3 | 30 | |
8b7f0bb3 | 31 | #include "libguile/async.h" |
d0f6ceb8 | 32 | #include "libguile/debug.h" |
a0599745 MD |
33 | #include "libguile/root.h" |
34 | #include "libguile/stackchk.h" | |
5f144b10 GH |
35 | #include "libguile/smob.h" |
36 | #include "libguile/ports.h" | |
9ede013f | 37 | #include "libguile/dynstack.h" |
9de87eea | 38 | #include "libguile/eval.h" |
bfffd258 | 39 | #include "libguile/vm.h" |
1d1cae0e | 40 | #include "libguile/instructions.h" |
5f144b10 | 41 | |
db4b4ca6 | 42 | #include "libguile/validate.h" |
a0599745 | 43 | #include "libguile/continuations.h" |
01c8a3dd | 44 | |
0f2d19dd JB |
45 | \f |
46 | ||
1d1cae0e AW |
47 | static scm_t_bits tc16_continuation; |
48 | #define SCM_CONTREGSP(x) SCM_TYP16_PREDICATE (tc16_continuation, x) | |
49 | ||
50 | #define SCM_CONTREGS(x) ((scm_t_contregs *) SCM_SMOB_DATA_1 (x)) | |
51 | ||
52 | #define SCM_CONTINUATION_LENGTH(x) (SCM_CONTREGS (x)->num_stack_items) | |
53 | #define SCM_SET_CONTINUATION_LENGTH(x, n)\ | |
54 | (SCM_CONTREGS (x)->num_stack_items = (n)) | |
55 | #define SCM_JMPBUF(x) ((SCM_CONTREGS (x))->jmpbuf) | |
1d1cae0e AW |
56 | #define SCM_CONTINUATION_ROOT(x) ((SCM_CONTREGS (x))->root) |
57 | #define SCM_DFRAME(x) ((SCM_CONTREGS (x))->dframe) | |
58 | ||
59 | \f | |
60 | ||
d691ac20 AW |
61 | /* scm_i_make_continuation will return a procedure whose code will |
62 | reinstate the continuation. Here, as in gsubr.c, we define the form | |
63 | of that trampoline function. | |
0f2d19dd JB |
64 | */ |
65 | ||
d691ac20 AW |
66 | static const scm_t_uint32 continuation_stub_code[] = |
67 | { | |
095100bb | 68 | SCM_PACK_OP_24 (continuation_call, 0) |
d691ac20 | 69 | }; |
1d1cae0e | 70 | |
1d1cae0e AW |
71 | static SCM |
72 | make_continuation_trampoline (SCM contregs) | |
73 | { | |
d691ac20 AW |
74 | SCM ret; |
75 | scm_t_bits nfree = 1; | |
76 | scm_t_bits flags = SCM_F_PROGRAM_IS_CONTINUATION; | |
77 | ||
e0755cd1 | 78 | ret = scm_words (scm_tc7_program | (nfree << 16) | flags, nfree + 2); |
d691ac20 | 79 | SCM_SET_CELL_WORD_1 (ret, continuation_stub_code); |
d798a895 | 80 | SCM_PROGRAM_FREE_VARIABLE_SET (ret, 0, contregs); |
1d1cae0e AW |
81 | |
82 | return ret; | |
83 | } | |
84 | ||
85 | ||
86 | /* {Continuations} | |
87 | */ | |
0f2d19dd | 88 | |
01c8a3dd | 89 | |
e841c3e0 | 90 | static int |
e81d98ec | 91 | continuation_print (SCM obj, SCM port, scm_print_state *state SCM_UNUSED) |
5f144b10 | 92 | { |
92c2555f | 93 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
5f144b10 | 94 | |
0607ebbf | 95 | scm_puts_unlocked ("#<continuation ", port); |
5f144b10 | 96 | scm_intprint (continuation->num_stack_items, 10, port); |
0607ebbf | 97 | scm_puts_unlocked (" @ ", port); |
0236bc68 | 98 | scm_uintprint (SCM_SMOB_DATA_1 (obj), 16, port); |
0607ebbf | 99 | scm_putc_unlocked ('>', port); |
5f144b10 GH |
100 | return 1; |
101 | } | |
1cc91f1b | 102 | |
2acdd822 AW |
103 | /* James Clark came up with this neat one instruction fix for |
104 | * continuations on the SPARC. It flushes the register windows so | |
105 | * that all the state of the process is contained in the stack. | |
106 | */ | |
107 | ||
108 | #if defined (sparc) || defined (__sparc__) || defined (__sparc) | |
109 | # define SCM_FLUSH_REGISTER_WINDOWS asm("ta 3") | |
110 | #else | |
111 | # define SCM_FLUSH_REGISTER_WINDOWS /* empty */ | |
112 | #endif | |
113 | ||
5f144b10 | 114 | /* this may return more than once: the first time with the escape |
d8873dfe AW |
115 | procedure, then subsequently with SCM_UNDEFINED (the vals already having been |
116 | placed on the VM stack). */ | |
997659f8 | 117 | #define FUNC_NAME "scm_i_make_continuation" |
0f2d19dd | 118 | SCM |
796e54a7 | 119 | scm_i_make_continuation (int *first, struct scm_vm *vp, SCM vm_cont) |
0f2d19dd | 120 | { |
9de87eea MV |
121 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; |
122 | SCM cont; | |
92c2555f | 123 | scm_t_contregs *continuation; |
c014a02e | 124 | long stack_size; |
01c8a3dd | 125 | SCM_STACKITEM * src; |
0f2d19dd | 126 | |
0f2d19dd | 127 | SCM_FLUSH_REGISTER_WINDOWS; |
9de87eea | 128 | stack_size = scm_stack_size (thread->continuation_base); |
4c9419ac MV |
129 | continuation = scm_gc_malloc (sizeof (scm_t_contregs) |
130 | + (stack_size - 1) * sizeof (SCM_STACKITEM), | |
131 | "continuation"); | |
5f144b10 | 132 | continuation->num_stack_items = stack_size; |
9de87eea | 133 | continuation->root = thread->continuation_root; |
9de87eea | 134 | src = thread->continuation_base; |
4ccb2cd2 | 135 | #if ! SCM_STACK_GROWS_UP |
5f144b10 GH |
136 | src -= stack_size; |
137 | #endif | |
5c5c27dc | 138 | continuation->offset = continuation->stack - src; |
5f144b10 | 139 | memcpy (continuation->stack, src, sizeof (SCM_STACKITEM) * stack_size); |
796e54a7 | 140 | continuation->vp = vp; |
269479e3 | 141 | continuation->vm_cont = vm_cont; |
5f144b10 | 142 | |
1d1cae0e | 143 | SCM_NEWSMOB (cont, tc16_continuation, continuation); |
79824460 | 144 | |
a4dbe1ac | 145 | *first = !SCM_I_SETJMP (continuation->jmpbuf); |
346e4402 | 146 | if (*first) |
193297d8 | 147 | { |
346e4402 | 148 | #ifdef __ia64__ |
9a5fa6e9 | 149 | continuation->backing_store_size = |
346e4402 | 150 | (char *) scm_ia64_ar_bsp(&continuation->jmpbuf.ctx) |
9a5fa6e9 | 151 | - |
346e4402 | 152 | (char *) thread->register_backing_store_base; |
193297d8 RB |
153 | continuation->backing_store = NULL; |
154 | continuation->backing_store = | |
4c9419ac MV |
155 | scm_gc_malloc (continuation->backing_store_size, |
156 | "continuation backing store"); | |
193297d8 | 157 | memcpy (continuation->backing_store, |
346e4402 | 158 | (void *) thread->register_backing_store_base, |
193297d8 | 159 | continuation->backing_store_size); |
346e4402 | 160 | #endif /* __ia64__ */ |
1d1cae0e | 161 | return make_continuation_trampoline (cont); |
193297d8 RB |
162 | } |
163 | else | |
c2247b78 AW |
164 | { |
165 | scm_gc_after_nonlocal_exit (); | |
166 | return SCM_UNDEFINED; | |
167 | } | |
0f2d19dd | 168 | } |
5f144b10 | 169 | #undef FUNC_NAME |
0f2d19dd | 170 | |
1d1cae0e AW |
171 | SCM |
172 | scm_i_continuation_to_frame (SCM continuation) | |
173 | { | |
174 | SCM contregs; | |
175 | scm_t_contregs *cont; | |
176 | ||
d798a895 | 177 | contregs = SCM_PROGRAM_FREE_VARIABLE_REF (continuation, 0); |
1d1cae0e AW |
178 | cont = SCM_CONTREGS (contregs); |
179 | ||
269479e3 | 180 | if (scm_is_true (cont->vm_cont)) |
1d1cae0e | 181 | { |
8de051da | 182 | struct scm_frame frame; |
269479e3 | 183 | struct scm_vm_cont *data = SCM_VM_CONT_DATA (cont->vm_cont); |
8de051da AW |
184 | |
185 | frame.stack_holder = data; | |
186 | frame.fp_offset = (data->fp + data->reloc) - data->stack_base; | |
187 | frame.sp_offset = (data->sp + data->reloc) - data->stack_base; | |
188 | frame.ip = data->ra; | |
189 | ||
190 | return scm_c_make_frame (SCM_VM_FRAME_KIND_CONT, &frame); | |
1d1cae0e AW |
191 | } |
192 | else | |
193 | return SCM_BOOL_F; | |
194 | } | |
195 | ||
796e54a7 AW |
196 | struct scm_vm * |
197 | scm_i_contregs_vp (SCM contregs) | |
d8873dfe | 198 | { |
796e54a7 | 199 | return SCM_CONTREGS (contregs)->vp; |
d8873dfe AW |
200 | } |
201 | ||
202 | SCM | |
203 | scm_i_contregs_vm_cont (SCM contregs) | |
204 | { | |
205 | return SCM_CONTREGS (contregs)->vm_cont; | |
206 | } | |
207 | ||
1d1cae0e AW |
208 | |
209 | /* {Apply} | |
210 | */ | |
d3c6aef9 MV |
211 | |
212 | /* Invoking a continuation proceeds as follows: | |
213 | * | |
214 | * - the stack is made large enough for the called continuation | |
215 | * - the old windchain is unwound down to the branching point | |
216 | * - the continuation stack is copied into place | |
217 | * - the windchain is rewound up to the continuation's context | |
218 | * - the continuation is invoked via longjmp (or setcontext) | |
219 | * | |
220 | * This order is important so that unwind and rewind handlers are run | |
221 | * with their correct stack. | |
222 | */ | |
223 | ||
d8873dfe | 224 | static void scm_dynthrow (SCM); |
01c8a3dd DH |
225 | |
226 | /* Grow the stack by a fixed amount to provide space to copy in the | |
227 | * continuation. Possibly this function has to be called several times | |
228 | * recursively before enough space is available. Make sure the compiler does | |
229 | * not optimize the growth array away by storing it's address into a global | |
230 | * variable. | |
231 | */ | |
232 | ||
8c93b597 | 233 | static scm_t_bits scm_i_dummy; |
1cc91f1b | 234 | |
0f2d19dd | 235 | static void |
d8873dfe | 236 | grow_stack (SCM cont) |
01c8a3dd | 237 | { |
92c2555f | 238 | scm_t_bits growth[100]; |
01c8a3dd | 239 | |
92c2555f | 240 | scm_i_dummy = (scm_t_bits) growth; |
d8873dfe | 241 | scm_dynthrow (cont); |
0f2d19dd | 242 | } |
0f2d19dd | 243 | |
1cc91f1b | 244 | |
01c8a3dd DH |
245 | /* Copy the continuation stack into the current stack. Calling functions from |
246 | * within this function is safe, since only stack frames below this function's | |
247 | * own frame are overwritten. Thus, memcpy can be used for best performance. | |
248 | */ | |
d3c6aef9 | 249 | |
d3c6aef9 | 250 | static void |
d8873dfe | 251 | copy_stack_and_call (scm_t_contregs *continuation, |
5f144b10 | 252 | SCM_STACKITEM * dst) |
0f2d19dd | 253 | { |
9ede013f AW |
254 | scm_t_dynstack *dynstack; |
255 | scm_t_bits *joint; | |
256 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; | |
257 | ||
258 | dynstack = SCM_VM_CONT_DATA (continuation->vm_cont)->dynstack; | |
259 | ||
260 | joint = scm_dynstack_unwind_fork (&thread->dynstack, dynstack); | |
261 | ||
262 | memcpy (dst, continuation->stack, | |
263 | sizeof (SCM_STACKITEM) * continuation->num_stack_items); | |
264 | #ifdef __ia64__ | |
265 | thread->pending_rbs_continuation = continuation; | |
266 | #endif | |
d3c6aef9 | 267 | |
9ede013f | 268 | scm_dynstack_wind (&thread->dynstack, joint); |
01c8a3dd | 269 | |
a4dbe1ac | 270 | SCM_I_LONGJMP (continuation->jmpbuf, 1); |
01c8a3dd DH |
271 | } |
272 | ||
346e4402 NJ |
273 | #ifdef __ia64__ |
274 | void | |
a4dbe1ac | 275 | scm_ia64_longjmp (scm_i_jmp_buf *JB, int VAL) |
346e4402 NJ |
276 | { |
277 | scm_i_thread *t = SCM_I_CURRENT_THREAD; | |
278 | ||
279 | if (t->pending_rbs_continuation) | |
280 | { | |
281 | memcpy (t->register_backing_store_base, | |
282 | t->pending_rbs_continuation->backing_store, | |
283 | t->pending_rbs_continuation->backing_store_size); | |
284 | t->pending_rbs_continuation = NULL; | |
285 | } | |
286 | setcontext (&JB->ctx); | |
287 | } | |
288 | #endif | |
289 | ||
01c8a3dd DH |
290 | /* Call grow_stack until the stack space is large enough, then, as the current |
291 | * stack frame might get overwritten, let copy_stack_and_call perform the | |
292 | * actual copying and continuation calling. | |
293 | */ | |
294 | static void | |
d8873dfe | 295 | scm_dynthrow (SCM cont) |
01c8a3dd | 296 | { |
9de87eea | 297 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; |
92c2555f | 298 | scm_t_contregs *continuation = SCM_CONTREGS (cont); |
9de87eea | 299 | SCM_STACKITEM *dst = thread->continuation_base; |
01c8a3dd DH |
300 | SCM_STACKITEM stack_top_element; |
301 | ||
87f30eda | 302 | if (thread->critical_section_level) |
8b7f0bb3 MV |
303 | { |
304 | fprintf (stderr, "continuation invoked from within critical section.\n"); | |
305 | abort (); | |
306 | } | |
307 | ||
4ccb2cd2 | 308 | #if SCM_STACK_GROWS_UP |
5afcf08b | 309 | if (dst + continuation->num_stack_items >= &stack_top_element) |
d8873dfe | 310 | grow_stack (cont); |
0f2d19dd | 311 | #else |
5f144b10 | 312 | dst -= continuation->num_stack_items; |
c8a1bdc4 | 313 | if (dst <= &stack_top_element) |
d8873dfe | 314 | grow_stack (cont); |
0f2d19dd | 315 | #endif /* def SCM_STACK_GROWS_UP */ |
01c8a3dd | 316 | |
5f144b10 | 317 | SCM_FLUSH_REGISTER_WINDOWS; |
d8873dfe | 318 | copy_stack_and_call (continuation, dst); |
0f2d19dd JB |
319 | } |
320 | ||
db4b4ca6 | 321 | |
1d1cae0e | 322 | void |
d8873dfe | 323 | scm_i_check_continuation (SCM cont) |
0f2d19dd | 324 | { |
9de87eea | 325 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; |
92c2555f | 326 | scm_t_contregs *continuation = SCM_CONTREGS (cont); |
5f144b10 | 327 | |
d223c3fc | 328 | if (!scm_is_eq (continuation->root, thread->continuation_root)) |
1d1cae0e AW |
329 | scm_misc_error |
330 | ("%continuation-call", | |
331 | "invoking continuation would cross continuation barrier: ~A", | |
332 | scm_list_1 (cont)); | |
d8873dfe AW |
333 | } |
334 | ||
335 | void | |
336 | scm_i_reinstate_continuation (SCM cont) | |
337 | { | |
338 | scm_dynthrow (cont); | |
0f2d19dd | 339 | } |
0f2d19dd | 340 | |
9de87eea MV |
341 | SCM |
342 | scm_i_with_continuation_barrier (scm_t_catch_body body, | |
343 | void *body_data, | |
344 | scm_t_catch_handler handler, | |
43e01b1e NJ |
345 | void *handler_data, |
346 | scm_t_catch_handler pre_unwind_handler, | |
347 | void *pre_unwind_handler_data) | |
9de87eea MV |
348 | { |
349 | SCM_STACKITEM stack_item; | |
350 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; | |
351 | SCM old_controot; | |
352 | SCM_STACKITEM *old_contbase; | |
9de87eea MV |
353 | SCM result; |
354 | ||
355 | /* Establish a fresh continuation root. | |
356 | */ | |
357 | old_controot = thread->continuation_root; | |
358 | old_contbase = thread->continuation_base; | |
9de87eea MV |
359 | thread->continuation_root = scm_cons (thread->handle, old_controot); |
360 | thread->continuation_base = &stack_item; | |
9de87eea MV |
361 | |
362 | /* Call FUNC inside a catch all. This is now guaranteed to return | |
363 | directly and exactly once. | |
364 | */ | |
43e01b1e NJ |
365 | result = scm_c_catch (SCM_BOOL_T, |
366 | body, body_data, | |
367 | handler, handler_data, | |
368 | pre_unwind_handler, pre_unwind_handler_data); | |
9de87eea MV |
369 | |
370 | /* Return to old continuation root. | |
371 | */ | |
9de87eea MV |
372 | thread->continuation_base = old_contbase; |
373 | thread->continuation_root = old_controot; | |
374 | ||
375 | return result; | |
376 | } | |
377 | ||
e309f3bf AW |
378 | \f |
379 | ||
380 | static int | |
381 | should_print_backtrace (SCM tag, SCM stack) | |
382 | { | |
383 | return SCM_BACKTRACE_P | |
384 | && scm_is_true (stack) | |
385 | && scm_initialized_p | |
386 | /* It's generally not useful to print backtraces for errors reading | |
387 | or expanding code in these fallback catch statements. */ | |
388 | && !scm_is_eq (tag, scm_from_latin1_symbol ("read-error")) | |
389 | && !scm_is_eq (tag, scm_from_latin1_symbol ("syntax-error")); | |
390 | } | |
391 | ||
392 | static void | |
393 | print_exception_and_backtrace (SCM port, SCM tag, SCM args) | |
394 | { | |
395 | SCM stack, frame; | |
396 | ||
397 | /* We get here via a throw to a catch-all. In that case there is the | |
398 | throw frame active, and this catch closure, so narrow by two | |
399 | frames. */ | |
400 | stack = scm_make_stack (SCM_BOOL_T, scm_list_1 (scm_from_int (2))); | |
401 | frame = scm_is_true (stack) ? scm_stack_ref (stack, SCM_INUM0) : SCM_BOOL_F; | |
402 | ||
403 | if (should_print_backtrace (tag, stack)) | |
404 | { | |
0607ebbf | 405 | scm_puts_unlocked ("Backtrace:\n", port); |
e309f3bf AW |
406 | scm_display_backtrace_with_highlights (stack, port, |
407 | SCM_BOOL_F, SCM_BOOL_F, | |
408 | SCM_EOL); | |
409 | scm_newline (port); | |
410 | } | |
411 | ||
412 | scm_print_exception (port, frame, tag, args); | |
413 | } | |
414 | ||
415 | \f | |
416 | ||
9de87eea MV |
417 | struct c_data { |
418 | void *(*func) (void *); | |
419 | void *data; | |
420 | void *result; | |
421 | }; | |
422 | ||
423 | static SCM | |
424 | c_body (void *d) | |
425 | { | |
426 | struct c_data *data = (struct c_data *)d; | |
427 | data->result = data->func (data->data); | |
428 | return SCM_UNSPECIFIED; | |
429 | } | |
430 | ||
431 | static SCM | |
432 | c_handler (void *d, SCM tag, SCM args) | |
433 | { | |
e309f3bf AW |
434 | struct c_data *data; |
435 | ||
436 | /* If TAG is `quit', exit() the process. */ | |
437 | if (scm_is_eq (tag, scm_from_latin1_symbol ("quit"))) | |
438 | exit (scm_exit_status (args)); | |
439 | ||
440 | data = (struct c_data *)d; | |
9de87eea MV |
441 | data->result = NULL; |
442 | return SCM_UNSPECIFIED; | |
443 | } | |
444 | ||
e309f3bf AW |
445 | static SCM |
446 | pre_unwind_handler (void *error_port, SCM tag, SCM args) | |
447 | { | |
448 | /* Print the exception unless TAG is `quit'. */ | |
449 | if (!scm_is_eq (tag, scm_from_latin1_symbol ("quit"))) | |
21041372 | 450 | print_exception_and_backtrace (SCM_PACK_POINTER (error_port), tag, args); |
e309f3bf AW |
451 | |
452 | return SCM_UNSPECIFIED; | |
453 | } | |
454 | ||
9de87eea MV |
455 | void * |
456 | scm_c_with_continuation_barrier (void *(*func) (void *), void *data) | |
457 | { | |
458 | struct c_data c_data; | |
459 | c_data.func = func; | |
460 | c_data.data = data; | |
461 | scm_i_with_continuation_barrier (c_body, &c_data, | |
43e01b1e | 462 | c_handler, &c_data, |
e309f3bf | 463 | pre_unwind_handler, |
21041372 | 464 | SCM_UNPACK_POINTER (scm_current_error_port ())); |
9de87eea MV |
465 | return c_data.result; |
466 | } | |
467 | ||
468 | struct scm_data { | |
469 | SCM proc; | |
470 | }; | |
471 | ||
472 | static SCM | |
473 | scm_body (void *d) | |
474 | { | |
475 | struct scm_data *data = (struct scm_data *)d; | |
476 | return scm_call_0 (data->proc); | |
477 | } | |
478 | ||
479 | static SCM | |
480 | scm_handler (void *d, SCM tag, SCM args) | |
481 | { | |
e309f3bf AW |
482 | /* Print a message. Note that if TAG is `quit', this will exit() the |
483 | process. */ | |
484 | scm_handle_by_message_noexit (NULL, tag, args); | |
485 | ||
9de87eea MV |
486 | return SCM_BOOL_F; |
487 | } | |
488 | ||
489 | SCM_DEFINE (scm_with_continuation_barrier, "with-continuation-barrier", 1,0,0, | |
490 | (SCM proc), | |
69d2000d MV |
491 | "Call @var{proc} and return its result. Do not allow the invocation of\n" |
492 | "continuations that would leave or enter the dynamic extent of the call\n" | |
493 | "to @code{with-continuation-barrier}. Such an attempt causes an error\n" | |
494 | "to be signaled.\n" | |
495 | "\n" | |
496 | "Throws (such as errors) that are not caught from within @var{proc} are\n" | |
497 | "caught by @code{with-continuation-barrier}. In that case, a short\n" | |
498 | "message is printed to the current error port and @code{#f} is returned.\n" | |
499 | "\n" | |
500 | "Thus, @code{with-continuation-barrier} returns exactly once.\n") | |
9de87eea MV |
501 | #define FUNC_NAME s_scm_with_continuation_barrier |
502 | { | |
503 | struct scm_data scm_data; | |
504 | scm_data.proc = proc; | |
505 | return scm_i_with_continuation_barrier (scm_body, &scm_data, | |
43e01b1e | 506 | scm_handler, &scm_data, |
e309f3bf | 507 | pre_unwind_handler, |
21041372 | 508 | SCM_UNPACK_POINTER (scm_current_error_port ())); |
9de87eea MV |
509 | } |
510 | #undef FUNC_NAME | |
db4b4ca6 | 511 | |
0f2d19dd JB |
512 | void |
513 | scm_init_continuations () | |
0f2d19dd | 514 | { |
1d1cae0e AW |
515 | tc16_continuation = scm_make_smob_type ("continuation", 0); |
516 | scm_set_smob_print (tc16_continuation, continuation_print); | |
a0599745 | 517 | #include "libguile/continuations.x" |
0f2d19dd JB |
518 | } |
519 | ||
89e00824 ML |
520 | /* |
521 | Local Variables: | |
522 | c-file-style: "gnu" | |
523 | End: | |
524 | */ |