3 /* Copyright (c) 2002,2003,2004 Arnaud Legrand. All rights reserved. */
5 /* This program is free software; you can redistribute it and/or modify it
6 * under the terms of the license (GNU LGPL) which comes with this package. */
9 #include "xbt/sysdep.h"
11 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(msg_gos, msg,
12 "Logging specific to MSG (gos)");
14 /** \defgroup msg_gos_functions MSG Operating System Functions
15 * \brief This section describes the functions that can be used
16 * by an agent for handling some task.
19 static MSG_error_t __MSG_task_get_with_time_out_from_host(m_task_t * task,
24 m_process_t process = MSG_process_self();
27 simdata_task_t t_simdata = NULL;
28 simdata_host_t h_simdata = NULL;
30 e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
31 xbt_fifo_item_t item = NULL;
34 xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
36 xbt_assert0(task,"Null pointer for the task\n");
39 CRITICAL0("MSG_task_get() was asked to write in a non empty task struct.");
43 h_simdata = h->simdata;
45 DEBUG2("Waiting for a task on channel %d (%s)", channel,h->name);
48 if(xbt_fifo_size(h_simdata->mbox[channel])>0) {
50 t = xbt_fifo_shift(h_simdata->mbox[channel]);
53 xbt_fifo_foreach(h->simdata->mbox[channel],item,t,m_task_t) {
54 if(t->simdata->source==host) break;
57 xbt_fifo_remove_item(h->simdata->mbox[channel],item);
68 xbt_assert3(!(h_simdata->sleeping[channel]),
69 "A process (%s(%d)) is already blocked on channel %d",
70 h_simdata->sleeping[channel]->name,
71 h_simdata->sleeping[channel]->simdata->PID,
73 h_simdata->sleeping[channel] = process; /* I'm waiting. Wake me up when you're ready */
75 __MSG_process_block(max_duration);
77 __MSG_process_block(-1);
79 h_simdata->sleeping[channel] = NULL;
81 if(surf_workstation_resource->extension_public->get_state(h_simdata->host)
83 MSG_RETURN(MSG_HOST_FAILURE);
84 /* OK, we should both be ready now. Are you there ? */
87 DEBUG1("OK, got a task (%s)", t->name);
89 t_simdata = t->simdata;
90 /* *task = __MSG_task_copy(t); */
96 while(MSG_process_is_suspended(t_simdata->sender)) {
97 DEBUG1("Oooups, the sender (%s) has been suspended in the meantime. Let's wait for him",
98 t_simdata->sender->name);
99 m_task_t task_to_wait_for = t_simdata->sender->simdata->waiting_task;
100 if(__MSG_process_isBlocked(t_simdata->sender)) {
101 DEBUG0("He's blocked. Let's wait for him to go in the suspended state");
102 __MSG_process_unblock(t_simdata->sender);
103 task_to_wait_for->simdata->using++;
104 __MSG_task_wait_event(process, task_to_wait_for);
105 MSG_task_destroy(task_to_wait_for);
107 DEBUG0("He's suspended. Let's wait for him to go in the resumed state");
108 task_to_wait_for->simdata->using++;
109 __MSG_task_wait_event(process, task_to_wait_for);
110 MSG_task_destroy(task_to_wait_for);
111 DEBUG0("He's resumed. He should block again. So let's free him.");
112 __MSG_process_unblock(t_simdata->sender);
116 DEBUG0("Calling SURF for communication creation");
117 t_simdata->comm = surf_workstation_resource->extension_public->
118 communicate(MSG_process_get_host(t_simdata->sender)->simdata->host,
119 h->simdata->host, t_simdata->message_size,t_simdata->rate);
121 surf_workstation_resource->common_public->action_set_data(t_simdata->comm,t);
123 if(__MSG_process_isBlocked(t_simdata->sender)) {
124 DEBUG1("Unblocking %s",t_simdata->sender->name);
125 __MSG_process_unblock(t_simdata->sender);
128 PAJE_PROCESS_PUSH_STATE(process,"C",t);
131 DEBUG0("Waiting for action termination");
132 __MSG_task_wait_event(process, t);
133 state=surf_workstation_resource->common_public->action_get_state(t_simdata->comm);
134 } while (state==SURF_ACTION_RUNNING);
135 DEBUG0("Action terminated");
137 if(t->simdata->using>1) {
138 xbt_fifo_unshift(msg_global->process_to_run,process);
142 PAJE_PROCESS_POP_STATE(process);
143 PAJE_COMM_STOP(process,t,channel);
145 if(state == SURF_ACTION_DONE) {
146 if(surf_workstation_resource->common_public->action_free(t_simdata->comm))
147 t_simdata->comm = NULL;
149 } else if(surf_workstation_resource->extension_public->get_state(h_simdata->host)
151 if(surf_workstation_resource->common_public->action_free(t_simdata->comm))
152 t_simdata->comm = NULL;
153 MSG_RETURN(MSG_HOST_FAILURE);
155 if(surf_workstation_resource->common_public->action_free(t_simdata->comm))
156 t_simdata->comm = NULL;
157 MSG_RETURN(MSG_TRANSFER_FAILURE);
161 /** \ingroup msg_gos_functions
162 * \brief Listen on a channel and wait for receiving a task.
164 * It takes two parameters.
165 * \param task a memory location for storing a #m_task_t. It will
166 hold a task when this function will return. Thus \a task should not
167 be equal to \c NULL and \a *task should be equal to \c NULL. If one of
168 those two condition does not hold, there will be a warning message.
169 * \param channel the channel on which the agent should be
170 listening. This value has to be >=0 and < than the maximal
171 number of channels fixed with MSG_set_channel_number().
172 * \return #MSG_FATAL if \a task is equal to \c NULL, #MSG_WARNING
173 * if \a *task is not equal to \c NULL, and #MSG_OK otherwise.
175 MSG_error_t MSG_task_get(m_task_t * task,
178 return MSG_task_get_with_time_out(task, channel, -1);
181 /** \ingroup msg_gos_functions
182 * \brief Listen on a channel and wait for receiving a task with a timeout.
184 * It takes three parameters.
185 * \param task a memory location for storing a #m_task_t. It will
186 hold a task when this function will return. Thus \a task should not
187 be equal to \c NULL and \a *task should be equal to \c NULL. If one of
188 those two condition does not hold, there will be a warning message.
189 * \param channel the channel on which the agent should be
190 listening. This value has to be >=0 and < than the maximal
191 number of channels fixed with MSG_set_channel_number().
192 * \param max_duration the maximum time to wait for a task before giving
193 up. In such a case, \a task will not be modified and will still be
194 equal to \c NULL when returning.
195 * \return #MSG_FATAL if \a task is equal to \c NULL, #MSG_WARNING
196 if \a *task is not equal to \c NULL, and #MSG_OK otherwise.
198 MSG_error_t MSG_task_get_with_time_out(m_task_t * task,
202 return __MSG_task_get_with_time_out_from_host(task, channel, max_duration, NULL);
205 /** \ingroup msg_gos_functions
206 * \brief Listen on \a channel and waits for receiving a task from \a host.
208 * It takes three parameters.
209 * \param task a memory location for storing a #m_task_t. It will
210 hold a task when this function will return. Thus \a task should not
211 be equal to \c NULL and \a *task should be equal to \c NULL. If one of
212 those two condition does not hold, there will be a warning message.
213 * \param channel the channel on which the agent should be
214 listening. This value has to be >=0 and < than the maximal
215 number of channels fixed with MSG_set_channel_number().
216 * \param host the host that is to be watched.
217 * \return #MSG_FATAL if \a task is equal to \c NULL, #MSG_WARNING
218 if \a *task is not equal to \c NULL, and #MSG_OK otherwise.
220 MSG_error_t MSG_task_get_from_host(m_task_t * task, int channel,
223 return __MSG_task_get_with_time_out_from_host(task, channel, -1, host);
226 /** \ingroup msg_gos_functions
227 * \brief Test whether there is a pending communication on a channel.
229 * It takes one parameter.
230 * \param channel the channel on which the agent should be
231 listening. This value has to be >=0 and < than the maximal
232 number of channels fixed with MSG_set_channel_number().
233 * \return 1 if there is a pending communication and 0 otherwise
235 int MSG_task_Iprobe(m_channel_t channel)
238 simdata_host_t h_simdata = NULL;
240 xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
241 DEBUG2("Probing on channel %d (%s)", channel,h->name);
244 h_simdata = h->simdata;
245 return(xbt_fifo_get_first_item(h_simdata->mbox[channel])!=NULL);
248 /** \ingroup msg_gos_functions
249 * \brief Test whether there is a pending communication on a channel, and who sent it.
251 * It takes one parameter.
252 * \param channel the channel on which the agent should be
253 listening. This value has to be >=0 and < than the maximal
254 number of channels fixed with MSG_set_channel_number().
255 * \return -1 if there is no pending communication and the PID of the process who sent it otherwise
257 int MSG_task_probe_from(m_channel_t channel)
260 simdata_host_t h_simdata = NULL;
261 xbt_fifo_item_t item;
264 xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
267 h_simdata = h->simdata;
269 DEBUG2("Probing on channel %d (%s)", channel,h->name);
271 item = xbt_fifo_get_first_item(h->simdata->mbox[channel]);
272 if (!item || !(t = xbt_fifo_get_item_content(item)))
275 return MSG_process_get_PID(t->simdata->sender);
278 /** \ingroup msg_gos_functions
279 * \brief Wait for at most \a max_duration second for a task reception
280 on \a channel. *\a PID is updated with the PID of the first process
281 that triggered this event if any.
283 * It takes three parameters:
284 * \param channel the channel on which the agent should be
285 listening. This value has to be >=0 and < than the maximal.
286 number of channels fixed with MSG_set_channel_number().
287 * \param PID a memory location for storing an int.
288 * \param max_duration the maximum time to wait for a task before
289 giving up. In the case of a reception, *\a PID will be updated
290 with the PID of the first process to send a task.
291 * \return #MSG_HOST_FAILURE if the host is shut down in the meantime
292 and #MSG_OK otherwise.
294 MSG_error_t MSG_channel_select_from(m_channel_t channel, double max_duration,
298 simdata_host_t h_simdata = NULL;
299 xbt_fifo_item_t item;
302 m_process_t process = MSG_process_self();
304 xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
309 if(max_duration==0.0) {
310 *PID = MSG_task_probe_from(channel);
315 h_simdata = h->simdata;
317 DEBUG2("Probing on channel %d (%s)", channel,h->name);
318 while(!(item = xbt_fifo_get_first_item(h->simdata->mbox[channel]))) {
324 xbt_assert2(!(h_simdata->sleeping[channel]),
325 "A process (%s(%d)) is already blocked on this channel",
326 h_simdata->sleeping[channel]->name,
327 h_simdata->sleeping[channel]->simdata->PID);
328 h_simdata->sleeping[channel] = process; /* I'm waiting. Wake me up when you're ready */
330 __MSG_process_block(max_duration);
332 __MSG_process_block(-1);
334 if(surf_workstation_resource->extension_public->get_state(h_simdata->host)
336 MSG_RETURN(MSG_HOST_FAILURE);
338 h_simdata->sleeping[channel] = NULL;
341 if (!item || !(t = xbt_fifo_get_item_content(item))) {
345 *PID = MSG_process_get_PID(t->simdata->sender);
352 /** \ingroup msg_gos_functions
354 * \brief Return the number of tasks waiting to be received on a \a
355 channel and sent by \a host.
357 * It takes two parameters.
358 * \param channel the channel on which the agent should be
359 listening. This value has to be >=0 and < than the maximal
360 number of channels fixed with MSG_set_channel_number().
361 * \param host the host that is to be watched.
362 * \return the number of tasks waiting to be received on \a channel
365 int MSG_task_probe_from_host(int channel, m_host_t host)
367 simdata_host_t h_simdata = NULL;
368 xbt_fifo_item_t item;
373 xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
376 h_simdata = h->simdata;
378 DEBUG2("Probing on channel %d (%s)", channel,h->name);
380 xbt_fifo_foreach(h->simdata->mbox[channel],item,t,m_task_t) {
381 if(t->simdata->source==host) count++;
387 /** \ingroup msg_gos_functions
388 * \brief Put a task on a channel of an host and waits for the end of the
391 * This function is used for describing the behavior of an agent. It
392 * takes three parameter.
393 * \param task a #m_task_t to send on another location. This task
394 will not be usable anymore when the function will return. There is
395 no automatic task duplication and you have to save your parameters
396 before calling this function. Tasks are unique and once it has been
397 sent to another location, you should not access it anymore. You do
398 not need to call MSG_task_destroy() but to avoid using, as an
399 effect of inattention, this task anymore, you definitely should
400 renitialize it with #MSG_TASK_UNINITIALIZED. Note that this task
401 can be transfered iff it has been correctly created with
403 * \param dest the destination of the message
404 * \param channel the channel on which the agent should put this
405 task. This value has to be >=0 and < than the maximal number of
406 channels fixed with MSG_set_channel_number().
407 * \return #MSG_FATAL if \a task is not properly initialized and
410 MSG_error_t MSG_task_put(m_task_t task,
411 m_host_t dest, m_channel_t channel)
413 m_process_t process = MSG_process_self();
414 simdata_task_t task_simdata = NULL;
415 e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
416 m_host_t local_host = NULL;
417 m_host_t remote_host = NULL;
421 xbt_assert1((channel>=0) && (channel < msg_global->max_channel),"Invalid channel %d",channel);
423 task_simdata = task->simdata;
424 task_simdata->sender = process;
425 task_simdata->source = MSG_process_get_host(process);
426 xbt_assert0(task_simdata->using==1,
427 "This taks is still being used somewhere else. You cannot send it now. Go fix your code!");
428 task_simdata->comm = NULL;
430 local_host = ((simdata_process_t) process->simdata)->host;
433 DEBUG4("Trying to send a task (%g Mb) from %s to %s on channel %d",
434 task->simdata->message_size,local_host->name, remote_host->name, channel);
436 xbt_fifo_push(((simdata_host_t) remote_host->simdata)->
437 mbox[channel], task);
439 PAJE_COMM_START(process,task,channel);
441 if(remote_host->simdata->sleeping[channel]) {
442 DEBUG0("Somebody is listening. Let's wake him up!");
443 __MSG_process_unblock(remote_host->simdata->sleeping[channel]);
446 process->simdata->put_host = dest;
447 process->simdata->put_channel = channel;
448 while(!(task_simdata->comm)) {
449 DEBUG0("Communication not initiated yet. Let's block!");
450 __MSG_process_block(-1);
451 if(surf_workstation_resource->extension_public->
452 get_state(local_host->simdata->host) == SURF_CPU_OFF) {
453 xbt_fifo_remove(((simdata_host_t) remote_host->simdata)->mbox[channel],
455 MSG_task_destroy(task);
456 MSG_RETURN(MSG_HOST_FAILURE);
459 DEBUG0("Registering to this communication");
460 surf_workstation_resource->common_public->action_use(task_simdata->comm);
461 process->simdata->put_host = NULL;
462 process->simdata->put_channel = -1;
465 PAJE_PROCESS_PUSH_STATE(process,"C",task);
467 state=surf_workstation_resource->common_public->action_get_state(task_simdata->comm);
468 while (state==SURF_ACTION_RUNNING) {
469 DEBUG0("Waiting for action termination");
470 __MSG_task_wait_event(process, task);
471 state=surf_workstation_resource->common_public->action_get_state(task_simdata->comm);
473 DEBUG0("Action terminated");
474 task->simdata->rate=-1.0; /* Sets the rate back to default */
476 PAJE_PROCESS_POP_STATE(process);
478 if(state == SURF_ACTION_DONE) {
479 if(surf_workstation_resource->common_public->action_free(task_simdata->comm))
480 task_simdata->comm = NULL;
481 MSG_task_destroy(task);
483 } else if(surf_workstation_resource->extension_public->get_state(local_host->simdata->host)
485 if(surf_workstation_resource->common_public->action_free(task_simdata->comm))
486 task_simdata->comm = NULL;
487 MSG_task_destroy(task);
488 MSG_RETURN(MSG_HOST_FAILURE);
490 if(surf_workstation_resource->common_public->action_free(task_simdata->comm))
491 task_simdata->comm = NULL;
492 MSG_task_destroy(task);
493 MSG_RETURN(MSG_TRANSFER_FAILURE);
497 /** \ingroup msg_gos_functions
498 * \brief Does exactly the same as MSG_task_put but with a bounded transmition
503 MSG_error_t MSG_task_put_bounded(m_task_t task,
504 m_host_t dest, m_channel_t channel,
507 MSG_error_t res = MSG_OK;
508 task->simdata->rate=max_rate;
509 res = MSG_task_put(task, dest, channel);
513 /** \ingroup msg_gos_functions
514 * \brief Executes a task and waits for its termination.
516 * This function is used for describing the behavior of an agent. It
517 * takes only one parameter.
518 * \param task a #m_task_t to execute on the location on which the
520 * \return #MSG_FATAL if \a task is not properly initialized and
523 MSG_error_t MSG_task_execute(m_task_t task)
525 m_process_t process = MSG_process_self();
528 DEBUG1("Computing on %s", process->simdata->host->name);
530 __MSG_task_execute(process, task);
532 PAJE_PROCESS_PUSH_STATE(process,"E",task);
533 res = __MSG_wait_for_computation(process,task);
534 PAJE_PROCESS_POP_STATE(process);
538 void __MSG_task_execute(m_process_t process, m_task_t task)
540 simdata_task_t simdata = NULL;
544 simdata = task->simdata;
545 xbt_assert0((!simdata->compute)&&(task->simdata->using==1),
546 "This taks is executed somewhere else. Go fix your code!");
547 task->simdata->using++;
548 simdata->compute = surf_workstation_resource->extension_public->
549 execute(MSG_process_get_host(process)->simdata->host,
550 simdata->computation_amount);
551 surf_workstation_resource->common_public->
552 set_priority(simdata->compute, simdata->priority);
554 surf_workstation_resource->common_public->action_set_data(simdata->compute,task);
555 task->simdata->using--;
558 MSG_error_t __MSG_wait_for_computation(m_process_t process, m_task_t task)
560 e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
561 simdata_task_t simdata = task->simdata;
563 XBT_IN4("(%p(%s) %p(%s))",process,process->name,task,task->name);
566 __MSG_task_wait_event(process, task);
567 state=surf_workstation_resource->common_public->action_get_state(simdata->compute);
568 } while (state==SURF_ACTION_RUNNING);
572 if(state == SURF_ACTION_DONE) {
573 if(surf_workstation_resource->common_public->action_free(simdata->compute))
574 simdata->compute = NULL;
575 simdata->computation_amount = 0.0;
578 } else if(surf_workstation_resource->extension_public->
579 get_state(MSG_process_get_host(process)->simdata->host)
581 if(surf_workstation_resource->common_public->action_free(simdata->compute))
582 simdata->compute = NULL;
584 MSG_RETURN(MSG_HOST_FAILURE);
586 if(surf_workstation_resource->common_public->action_free(simdata->compute))
587 simdata->compute = NULL;
589 MSG_RETURN(MSG_TASK_CANCELLED);
592 /** \ingroup m_task_management
593 * \brief Creates a new #m_task_t (a parallel one....).
595 * A constructor for #m_task_t taking six arguments and returning the
596 corresponding object.
597 * \param name a name for the object. It is for user-level information
599 * \param host_nb the number of hosts implied in the parallel task.
600 * \param host_list an array of \p host_nb m_host_t.
601 * \param computation_amount an array of \p host_nb
602 doubles. computation_amount[i] is the total number of operations
603 that have to be performed on host_list[i].
604 * \param communication_amount an array of \p host_nb* \p host_nb doubles.
605 * \param data a pointer to any data may want to attach to the new
606 object. It is for user-level information and can be NULL. It can
607 be retrieved with the function \ref MSG_task_get_data.
609 * \return The new corresponding object.
611 m_task_t MSG_parallel_task_create(const char *name,
613 const m_host_t *host_list,
614 double *computation_amount,
615 double *communication_amount,
618 simdata_task_t simdata = xbt_new0(s_simdata_task_t,1);
619 m_task_t task = xbt_new0(s_m_task_t,1);
623 task->name = xbt_strdup(name);
624 task->simdata = simdata;
628 simdata->sleeping = xbt_dynar_new(sizeof(m_process_t),NULL);
629 simdata->rate = -1.0;
631 simdata->sender = NULL;
632 simdata->source = NULL;
633 simdata->host_nb = host_nb;
635 simdata->host_list = xbt_new0(void *, host_nb);
636 simdata->comp_amount = computation_amount;
637 simdata->comm_amount = communication_amount;
639 for(i=0;i<host_nb;i++)
640 simdata->host_list[i] = host_list[i]->simdata->host;
646 static void __MSG_parallel_task_execute(m_process_t process, m_task_t task)
648 simdata_task_t simdata = NULL;
652 simdata = task->simdata;
654 xbt_assert0(simdata->host_nb,"This is not a parallel task. Go to hell.");
656 simdata->compute = surf_workstation_resource->extension_public->
657 execute_parallel_task(task->simdata->host_nb,
658 task->simdata->host_list,
659 task->simdata->comp_amount,
660 task->simdata->comm_amount,
664 surf_workstation_resource->common_public->action_set_data(simdata->compute,task);
667 MSG_error_t MSG_parallel_task_execute(m_task_t task)
669 m_process_t process = MSG_process_self();
672 DEBUG0("Computing on a tons of guys");
674 __MSG_parallel_task_execute(process, task);
676 if(task->simdata->compute)
677 res = __MSG_wait_for_computation(process,task);
685 /** \ingroup msg_gos_functions
686 * \brief Sleep for the specified number of seconds
688 * Makes the current process sleep until \a time seconds have elapsed.
690 * \param nb_sec a number of second
692 MSG_error_t MSG_process_sleep(double nb_sec)
694 e_surf_action_state_t state = SURF_ACTION_NOT_IN_THE_SYSTEM;
695 m_process_t process = MSG_process_self();
696 m_task_t dummy = NULL;
697 simdata_task_t simdata = NULL;
700 dummy = MSG_task_create("MSG_sleep", nb_sec, 0.0, NULL);
701 simdata = dummy->simdata;
703 simdata->compute = surf_workstation_resource->extension_public->
704 sleep(MSG_process_get_host(process)->simdata->host,
705 simdata->computation_amount);
706 surf_workstation_resource->common_public->action_set_data(simdata->compute,dummy);
711 __MSG_task_wait_event(process, dummy);
712 state=surf_workstation_resource->common_public->action_get_state(simdata->compute);
713 } while (state==SURF_ACTION_RUNNING);
716 if(state == SURF_ACTION_DONE) {
717 if(surf_workstation_resource->extension_public->
718 get_state(MSG_process_get_host(process)->simdata->host)
720 if(surf_workstation_resource->common_public->action_free(simdata->compute))
721 simdata->compute = NULL;
722 MSG_RETURN(MSG_HOST_FAILURE);
724 if(__MSG_process_isBlocked(process)) {
725 __MSG_process_unblock(MSG_process_self());
727 if(surf_workstation_resource->extension_public->
728 get_state(MSG_process_get_host(process)->simdata->host)
730 if(surf_workstation_resource->common_public->action_free(simdata->compute))
731 simdata->compute = NULL;
732 MSG_RETURN(MSG_HOST_FAILURE);
734 if(surf_workstation_resource->common_public->action_free(simdata->compute))
735 simdata->compute = NULL;
736 MSG_task_destroy(dummy);
738 } else MSG_RETURN(MSG_HOST_FAILURE);
741 /** \ingroup msg_gos_functions
742 * \brief Return the number of MSG tasks currently running on
743 * the host of the current running process.
745 static int MSG_get_msgload(void)
751 xbt_assert0(0, "This function is still to be specified correctly (what do you mean by 'load', exactly?). In the meantime, please don't use it");
752 process = MSG_process_self();
753 return xbt_fifo_size(process->simdata->host->simdata->process_list);
756 /** \ingroup msg_gos_functions
758 * \brief Return the last value returned by a MSG function (except
761 MSG_error_t MSG_get_errno(void)
763 return PROCESS_GET_ERRNO();