bsd/sys/signal.h

   1 /*
   2  * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  29 /*
  30  * Copyright (c) 1982, 1986, 1989, 1991, 1993
  31  *      The Regents of the University of California.  All rights reserved.
  32  * (c) UNIX System Laboratories, Inc.
  33  * All or some portions of this file are derived from material licensed
  34  * to the University of California by American Telephone and Telegraph
  35  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  36  * the permission of UNIX System Laboratories, Inc.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. All advertising materials mentioning features or use of this software
  47  *    must display the following acknowledgement:
  48  *      This product includes software developed by the University of
  49  *      California, Berkeley and its contributors.
  50  * 4. Neither the name of the University nor the names of its contributors
  51  *    may be used to endorse or promote products derived from this software
  52  *    without specific prior written permission.
  53  *
  54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  64  * SUCH DAMAGE.
  65  *
  66  *      @(#)signal.h    8.2 (Berkeley) 1/21/94
  67  */
  68
  69 #ifndef _SYS_SIGNAL_H_
  70 #define _SYS_SIGNAL_H_
  71
  72 #include <sys/cdefs.h>
  73 #include <sys/appleapiopts.h>
  74
  75 #if !defined(_ANSI_SOURCE) && !defined(_POSIX_C_SOURCE)
  76 #define NSIG    32              /* counting 0; could be 33 (mask is 1-32) */
  77 #endif
  78
  79 #include <machine/signal.h>     /* sigcontext; codes for SIGILL, SIGFPE */
  80
  81 #define SIGHUP  1       /* hangup */
  82 #define SIGINT  2       /* interrupt */
  83 #define SIGQUIT 3       /* quit */
  84 #define SIGILL  4       /* illegal instruction (not reset when caught) */
  85 #define SIGTRAP 5       /* trace trap (not reset when caught) */
  86 #define SIGABRT 6       /* abort() */
  87 #if  defined(_POSIX_C_SOURCE)
  88 #define SIGPOLL 7       /* pollable event ([XSR] generated, not supported) */
  89 #else   /* !_POSIX_C_SOURCE */
  90 #define SIGIOT  SIGABRT /* compatibility */
  91 #define SIGEMT  7       /* EMT instruction */
  92 #endif  /* !_POSIX_C_SOURCE */
  93 #define SIGFPE  8       /* floating point exception */
  94 #define SIGKILL 9       /* kill (cannot be caught or ignored) */
  95 #define SIGBUS  10      /* bus error */
  96 #define SIGSEGV 11      /* segmentation violation */
  97 #define SIGSYS  12      /* bad argument to system call */
  98 #define SIGPIPE 13      /* write on a pipe with no one to read it */
  99 #define SIGALRM 14      /* alarm clock */
 100 #define SIGTERM 15      /* software termination signal from kill */
 101 #define SIGURG  16      /* urgent condition on IO channel */
 102 #define SIGSTOP 17      /* sendable stop signal not from tty */
 103 #define SIGTSTP 18      /* stop signal from tty */
 104 #define SIGCONT 19      /* continue a stopped process */
 105 #define SIGCHLD 20      /* to parent on child stop or exit */
 106 #define SIGTTIN 21      /* to readers pgrp upon background tty read */
 107 #define SIGTTOU 22      /* like TTIN for output if (tp->t_local&LTOSTOP) */
 108 #if  !defined(_POSIX_C_SOURCE)
 109 #define SIGIO   23      /* input/output possible signal */
 110 #endif
 111 #define SIGXCPU 24      /* exceeded CPU time limit */
 112 #define SIGXFSZ 25      /* exceeded file size limit */
 113 #define SIGVTALRM 26    /* virtual time alarm */
 114 #define SIGPROF 27      /* profiling time alarm */
 115 #if  !defined(_POSIX_C_SOURCE)
 116 #define SIGWINCH 28     /* window size changes */
 117 #define SIGINFO 29      /* information request */
 118 #endif
 119 #define SIGUSR1 30      /* user defined signal 1 */
 120 #define SIGUSR2 31      /* user defined signal 2 */
 121
 122 #if defined(_ANSI_SOURCE) || defined(_POSIX_C_SOURCE) || defined(__cplusplus)
 123 /*
 124  * Language spec sez we must list exactly one parameter, even though we
 125  * actually supply three.  Ugh!
 126  * SIG_HOLD is chosen to avoid KERN_SIG_* values in <sys/signalvar.h>
 127  */
 128 #define SIG_DFL         (void (*)(int))0
 129 #define SIG_IGN         (void (*)(int))1
 130 #define SIG_HOLD        (void (*)(int))5
 131 #define SIG_ERR         ((void (*)(int))-1)
 132 #else
 133 /* DO NOT REMOVE THE COMMENTED OUT int: fixincludes needs to see them */
 134 #define SIG_DFL         (void (*)(/*int*/))0
 135 #define SIG_IGN         (void (*)(/*int*/))1
 136 #define SIG_HOLD        (void (*)(/*int*/))5
 137 #define SIG_ERR         ((void (*)(/*int*/))-1)
 138 #endif
 139
 140 #ifndef _ANSI_SOURCE
 141 #include <sys/_types.h>
 142
 143 #ifndef _MCONTEXT_T
 144 #define _MCONTEXT_T
 145 typedef __darwin_mcontext_t             mcontext_t;
 146 #endif
 147
 148 #ifndef _POSIX_C_SOURCE
 149 #ifndef _MCONTEXT64_T
 150 #define _MCONTEXT64_T
 151 typedef __darwin_mcontext64_t           mcontext64_t;
 152 #endif
 153 #endif /* _POSIX_C_SOURCE */
 154
 155 #ifndef _PID_T
 156 #define _PID_T
 157 typedef __darwin_pid_t                  pid_t;
 158 #endif
 159
 160 #ifndef _PTHREAD_ATTR_T
 161 #define _PTHREAD_ATTR_T
 162 typedef __darwin_pthread_attr_t         pthread_attr_t;
 163 #endif
 164
 165 #ifndef _SIGSET_T
 166 #define _SIGSET_T
 167 typedef __darwin_sigset_t               sigset_t;
 168 #endif
 169
 170 #ifndef _SIZE_T
 171 #define _SIZE_T
 172 typedef __darwin_size_t                 size_t;
 173 #endif
 174
 175 #ifndef _UCONTEXT_T
 176 #define _UCONTEXT_T
 177 typedef __darwin_ucontext_t             ucontext_t;
 178 #endif
 179
 180 #ifndef _POSIX_C_SOURCE
 181 #ifndef _UCONTEXT64_T
 182 #define _UCONTEXT64_T
 183 typedef __darwin_ucontext64_t           ucontext64_t;
 184 #endif
 185 #endif /* _POSIX_C_SOURCE */
 186
 187 #ifndef _UID_T
 188 #define _UID_T
 189 typedef __darwin_uid_t                  uid_t;
 190 #endif
 191
 192 union sigval {
 193         /* Members as suggested by Annex C of POSIX 1003.1b. */
 194         int     sival_int;
 195         void    *sival_ptr;
 196 };
 197
 198 #define SIGEV_NONE      0               /* No async notification */
 199 #define SIGEV_SIGNAL    1               /* aio - completion notification */
 200 #define SIGEV_THREAD    3               /* A notification function will be called to perform notification */
 201
 202 struct sigevent {
 203         int                             sigev_notify;                           /* Notification type */
 204         int                             sigev_signo;                            /* Signal number */
 205         union sigval    sigev_value;                            /* Signal value */
 206         void                    (*sigev_notify_function)(union sigval);   /* Notification function */
 207         pthread_attr_t  *sigev_notify_attributes;       /* Notification attributes */
 208 };
 209
 210 // LP64todo - should this move?
 211 #ifdef BSD_KERNEL_PRIVATE
 212
 213 union user_sigval {
 214         struct {
 215                 int             pad;    /* assumes Motorolla byte order */
 216                 int             sival_int;
 217         } size_equivalent;
 218         user_addr_t     sival_ptr;
 219 };
 220
 221 struct user_sigevent {
 222         int             sigev_notify;                   /* Notification type */
 223         int             sigev_signo;                    /* Signal number */
 224         union user_sigval sigev_value;                  /* Signal value */
 225         user_addr_t     sigev_notify_function;          /* Notify function */
 226         user_addr_t     sigev_notify_attributes;        /* Notify attributes */
 227 };
 228
 229 #endif  /* BSD_KERNEL_PRIVATE */
 230
 231 typedef struct __siginfo {
 232         int     si_signo;               /* signal number */
 233         int     si_errno;               /* errno association */
 234         int     si_code;                /* signal code */
 235         pid_t   si_pid;                 /* sending process */
 236         uid_t   si_uid;                 /* sender's ruid */
 237         int     si_status;              /* exit value */
 238         void    *si_addr;               /* faulting instruction */
 239         union sigval si_value;          /* signal value */
 240         long    si_band;                /* band event for SIGPOLL */
 241         unsigned long   pad[7];         /* Reserved for Future Use */
 242 } siginfo_t;
 243
 244 #ifdef BSD_KERNEL_PRIVATE
 245
 246 typedef struct __user_siginfo {
 247         int             si_signo;       /* signal number */
 248         int             si_errno;       /* errno association */
 249         int             si_code;        /* signal code */
 250         pid_t           si_pid;         /* sending process */
 251         uid_t           si_uid;         /* sender's ruid */
 252         int             si_status;      /* exit value */
 253         user_addr_t     si_addr;        /* faulting instruction */
 254         union user_sigval si_value;     /* signal value */
 255         user_long_t     si_band;        /* band event for SIGPOLL */
 256         user_ulong_t    pad[7];         /* Reserved for Future Use */
 257 } user_siginfo_t;
 258
 259 #endif  /* BSD_KERNEL_PRIVATE */
 260
 261 /*
 262  * Incase of SIGILL and SIGFPE, si_addr contains the address of
 263  *  faulting instruction.
 264  * Incase of SIGSEGV and SIGBUS, si_addr contains address of
 265  *  faulting memory reference.
 266  * Incase of SIGCHLD, si_pid willhave child process ID,
 267  *  si_status will contain exit value or signal.
 268  *  si_uid contains real user ID of the process that sent the signal
 269  */
 270
 271 /* Values for si_code */
 272
 273 /* Codes for SIGILL */
 274 #ifndef _POSIX_C_SOURCE
 275 #define ILL_NOOP        0       /* if only I knew... */
 276 #endif
 277 #define ILL_ILLOPC      1       /* [XSI] illegal opcode */
 278 #define ILL_ILLTRP      2       /* [XSI] illegal trap */
 279 #define ILL_PRVOPC      3       /* [XSI] privileged opcode */
 280 #define ILL_ILLOPN      4       /* [XSI] illegal operand -NOTIMP */
 281 #define ILL_ILLADR      5       /* [XSI] illegal addressing mode -NOTIMP */
 282 #define ILL_PRVREG      6       /* [XSI] privileged register -NOTIMP */
 283 #define ILL_COPROC      7       /* [XSI] coprocessor error -NOTIMP */
 284 #define ILL_BADSTK      8       /* [XSI] internal stack error -NOTIMP */
 285
 286 /* Codes for SIGFPE */
 287 #ifndef _POSIX_C_SOURCE
 288 #define FPE_NOOP        0       /* if only I knew... */
 289 #endif
 290 #define FPE_FLTDIV      1       /* [XSI] floating point divide by zero */
 291 #define FPE_FLTOVF      2       /* [XSI] floating point overflow */
 292 #define FPE_FLTUND      3       /* [XSI] floating point underflow */
 293 #define FPE_FLTRES      4       /* [XSI] floating point inexact result */
 294 #define FPE_FLTINV      5       /* [XSI] invalid floating point operation */
 295 #define FPE_FLTSUB      6       /* [XSI] subscript out of range -NOTIMP */
 296 #define FPE_INTDIV      7       /* [XSI] integer divide by zero -NOTIMP */
 297 #define FPE_INTOVF      8       /* [XSI] integer overflow -NOTIMP */
 298
 299 /* Codes for SIGSEGV */
 300 #ifndef _POSIX_C_SOURCE
 301 #define SEGV_NOOP       0       /* if only I knew... */
 302 #endif
 303 #define SEGV_MAPERR     1       /* [XSI] address not mapped to object */
 304 #define SEGV_ACCERR     2       /* [XSI] invalid permission for mapped object */
 305
 306 /* Codes for SIGBUS */
 307 #ifndef _POSIX_C_SOURCE
 308 #define BUS_NOOP        0       /* if only I knew... */
 309 #endif
 310 #define BUS_ADRALN      1       /* [XSI] Invalid address alignment */
 311 #define BUS_ADRERR      2       /* [XSI] Nonexistent physical address -NOTIMP */
 312 #define BUS_OBJERR      3       /* [XSI] Object-specific HW error - NOTIMP */
 313
 314 /* Codes for SIGTRAP */
 315 #define TRAP_BRKPT      1       /* [XSI] Process breakpoint -NOTIMP */
 316 #define TRAP_TRACE      2       /* [XSI] Process trace trap -NOTIMP */
 317
 318 /* Codes for SIGCHLD */
 319 #ifndef _POSIX_C_SOURCE
 320 #define CLD_NOOP        0       /* if only I knew... */
 321 #endif
 322 #define CLD_EXITED      1       /* [XSI] child has exited */
 323 #define CLD_KILLED      2       /* [XSI] terminated abnormally, no core file */
 324 #define CLD_DUMPED      3       /* [XSI] terminated abnormally, core file */
 325 #define CLD_TRAPPED     4       /* [XSI] traced child has trapped */
 326 #define CLD_STOPPED     5       /* [XSI] child has stopped */
 327 #define CLD_CONTINUED   6       /* [XSI] stopped child has continued */
 328
 329 /* Codes for SIGPOLL */
 330 #define POLL_IN         1       /* [XSR] Data input available */
 331 #define POLL_OUT        2       /* [XSR] Output buffers available */
 332 #define POLL_MSG        3       /* [XSR] Input message available */
 333 #define POLL_ERR        4       /* [XSR] I/O error */
 334 #define POLL_PRI        5       /* [XSR] High priority input available */
 335 #define POLL_HUP        6       /* [XSR] Device disconnected */
 336
 337 /* union for signal handlers */
 338 union __sigaction_u {
 339         void    (*__sa_handler)(int);
 340         void    (*__sa_sigaction)(int, struct __siginfo *,
 341                        void *);
 342 };
 343
 344 /* Signal vector template for Kernel user boundary */
 345 struct  __sigaction {
 346         union __sigaction_u __sigaction_u;  /* signal handler */
 347         void    (*sa_tramp)(void *, int, int, siginfo_t *, void *);
 348         sigset_t sa_mask;               /* signal mask to apply */
 349         int     sa_flags;               /* see signal options below */
 350 };
 351
 352 /*
 353  * Signal vector "template" used in sigaction call.
 354  */
 355 struct  sigaction {
 356         union __sigaction_u __sigaction_u;  /* signal handler */
 357         sigset_t sa_mask;               /* signal mask to apply */
 358         int     sa_flags;               /* see signal options below */
 359 };
 360
 361 #ifdef  BSD_KERNEL_PRIVATE
 362 #include <machine/types.h>
 363
 364 union __user_sigaction_u {
 365         user_addr_t     __sa_handler;
 366         user_addr_t     __sa_sigaction;
 367 };
 368
 369 struct  user_sigaction {
 370         union __user_sigaction_u __sigaction_u;  /* signal handler */
 371         sigset_t sa_mask;               /* signal mask to apply */
 372         int     sa_flags;               /* see signal options below */
 373 };
 374
 375 struct  __user_sigaction {
 376         union __user_sigaction_u __sigaction_u;  /* signal handler */
 377         user_addr_t     sa_tramp;       /* signal mask to apply */
 378         sigset_t sa_mask;               /* signal mask to apply */
 379         int     sa_flags;               /* see signal options below */
 380 };
 381
 382 #undef SIG_DFL
 383 #undef SIG_IGN
 384 #undef SIG_ERR
 385 #define  SIG_DFL        ((user_addr_t)0LL)
 386 #define  SIG_IGN        ((user_addr_t)1LL)
 387 #define  SIG_ERR        ((user_addr_t)-1LL)
 388
 389 #endif  /* BSD_KERNEL_PRIVATE */
 390
 391
 392 /* if SA_SIGINFO is set, sa_sigaction is to be used instead of sa_handler. */
 393 #define sa_handler      __sigaction_u.__sa_handler
 394 #define sa_sigaction    __sigaction_u.__sa_sigaction
 395
 396 #define SA_ONSTACK      0x0001  /* take signal on signal stack */
 397 #define SA_RESTART      0x0002  /* restart system on signal return */
 398 #define SA_DISABLE      0x0004  /* disable taking signals on alternate stack */
 399 #define SA_RESETHAND    0x0004  /* reset to SIG_DFL when taking signal */
 400 #define SA_NOCLDSTOP    0x0008  /* do not generate SIGCHLD on child stop */
 401 #define SA_NODEFER      0x0010  /* don't mask the signal we're delivering */
 402 #define SA_NOCLDWAIT    0x0020  /* don't keep zombies around */
 403 #define SA_SIGINFO      0x0040  /* signal handler with SA_SIGINFO args */
 404 #ifndef _POSIX_C_SOURCE
 405 #define SA_USERTRAMP    0x0100  /* do not bounce off kernel's sigtramp */
 406 /* This will provide 64bit register set in a 32bit user address space */
 407 #define SA_64REGSET     0x0200  /* signal handler with SA_SIGINFO args with 64bit regs information */
 408 #endif /* !_POSIX_C_SOURCE */
 409
 410 /*
 411  * Flags for sigprocmask:
 412  */
 413 #define SIG_BLOCK       1       /* block specified signal set */
 414 #define SIG_UNBLOCK     2       /* unblock specified signal set */
 415 #define SIG_SETMASK     3       /* set specified signal set */
 416
 417 /* POSIX 1003.1b required values. */
 418 #define SI_USER         0x10001 /* [CX] signal from kill() */
 419 #define SI_QUEUE        0x10002 /* [CX] signal from sigqueue() */
 420 #define SI_TIMER        0x10003 /* [CX] timer expiration */
 421 #define SI_ASYNCIO      0x10004 /* [CX] aio request completion */
 422 #define SI_MESGQ        0x10005 /* [CX] from message arrival on empty queue */
 423
 424 #ifndef _POSIX_C_SOURCE
 425 typedef void (*sig_t)(int);     /* type of signal function */
 426 #endif
 427
 428 /*
 429  * Structure used in sigaltstack call.
 430  */
 431 #ifdef  BSD_KERNEL_PRIVATE
 432
 433 struct  user_sigaltstack {
 434         user_addr_t     ss_sp;          /* signal stack base */
 435         user_size_t     ss_size;        /* signal stack length */
 436         int             ss_flags __attribute((aligned(8)));     /* SA_DISABLE and/or SA_ONSTACK */
 437 };
 438
 439 #endif  /* BSD_KERNEL_PRIVATE */
 440
 441 #ifndef _STACK_T
 442 #define _STACK_T
 443 typedef __darwin_stack_t stack_t;
 444 #endif
 445
 446 #define SS_ONSTACK      0x0001  /* take signal on signal stack */
 447 #define SS_DISABLE      0x0004  /* disable taking signals on alternate stack */
 448 #define MINSIGSTKSZ     32768   /* (32K)minimum allowable stack */
 449 #define SIGSTKSZ        131072  /* (128K)recommended stack size */
 450
 451 #ifndef _POSIX_C_SOURCE
 452 /*
 453  * 4.3 compatibility:
 454  * Signal vector "template" used in sigvec call.
 455  */
 456 struct  sigvec {
 457         void    (*sv_handler)(int);     /* signal handler */
 458         int     sv_mask;                /* signal mask to apply */
 459         int     sv_flags;               /* see signal options below */
 460 };
 461
 462 #define SV_ONSTACK      SA_ONSTACK
 463 #define SV_INTERRUPT    SA_RESTART      /* same bit, opposite sense */
 464 #define SV_RESETHAND    SA_RESETHAND
 465 #define SV_NODEFER      SA_NODEFER
 466 #define SV_NOCLDSTOP    SA_NOCLDSTOP
 467 #define SV_SIGINFO      SA_SIGINFO
 468
 469 #define sv_onstack sv_flags     /* isn't compatibility wonderful! */
 470 #endif /* !_POSIX_C_SOURCE */
 471
 472 /*
 473  * Structure used in sigstack call.
 474  */
 475 struct  sigstack {
 476         char    *ss_sp;                 /* signal stack pointer */
 477         int     ss_onstack;             /* current status */
 478 };
 479
 480 #ifndef _POSIX_C_SOURCE
 481 /*
 482  * Macro for converting signal number to a mask suitable for
 483  * sigblock().
 484  */
 485 #define sigmask(m)      (1 << ((m)-1))
 486
 487 #ifdef  BSD_KERNEL_PRIVATE
 488 /*
 489  *      signals delivered on a per-thread basis.
 490  */
 491 #define threadmask (sigmask(SIGILL)|sigmask(SIGTRAP)|\
 492                     sigmask(SIGIOT)|sigmask(SIGEMT)|\
 493                     sigmask(SIGFPE)|sigmask(SIGBUS)|\
 494                     sigmask(SIGSEGV)|sigmask(SIGSYS)|\
 495                     sigmask(SIGPIPE))
 496 #endif  /* BSD_KERNEL_PRIVATE */
 497
 498 #define BADSIG          SIG_ERR
 499
 500 #endif  /* !_POSIX_C_SOURCE */
 501 #endif  /* !_ANSI_SOURCE */
 502
 503 /*
 504  * For historical reasons; programs expect signal's return value to be
 505  * defined by <sys/signal.h>.
 506  */
 507 __BEGIN_DECLS
 508 void    (*signal(int, void (*)(int)))(int);
 509 __END_DECLS
 510 #endif  /* !_SYS_SIGNAL_H_ */