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$B"#(B $B4X?t8F$S=P$7$OF14|=hM}!$3d$j9~$_$OHsF14|=hM}(B

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$B"#(B $B3d$j9~$_$rCj>]2=$7$?$N$,%7%0%J%k(B

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$B%W%m%;%930It$+$i$N%$%Y%s%H$H$7$FNI$/;HMQ$5$l$F$$$k$N$,!$%-!<%\!<%I$+$i(B Ctrl-C $B$d(B Ctrl-Z $B$K$h$k%W%m%;%9

$B%7%0%J%k$rMQ$$$?%W%m%0%i%_%s%0(B

$B%7%0%J%k$N

SIGNAL(7)           Linux Programmer's Manual           SIGNAL(7)

$BL>A0(B
       signal - $BM-8z$J%7%0%J%k$N0lMw(B

$B@bL@(B
       Linux $B$,%5%]!<%H$9$k%7%0%J%k$N0lMw$r0J2<$K<($9!#%7%0%J%kHV9f$N4v$D$+$O(B
       $B%"!<%-%F%#%/%A%c0MB8$G$"$k!#:G=i$K!"(BPOSIX.1$B$KDj5A$5$l$F$$$k%7%0%J%k$r<($9!#(B

       $B%7%0%J%k(B      $BCM(B      $BF0:n(B   $B%3%a%s%H(B
       --------------------------------------------------------------------------
       SIGHUP         1       A     $B@)8f$7$F$$$k%?!<%_%J%k(B(controlling terminal)
                                    $B$N%O%s%0%"%C%W$r8!=P$7$?!#$"$k$$$O!"@)8f$7$F(B
                                    $B$$$k%W%m%;%9(B(controlling process)$B$,;`$s$@!#(B
       SIGINT         2       A     $B%-!<%\!<%I$+$i$N3d$j9~$_(B(Interrupt)
       SIGQUIT        3       A     $B%-!<%\!<%I$K$h$kCf;_(B(Quit)
       SIGILL         4       A     $BITEv$JL?Na(B
       SIGABRT        6       C     abort(3)$B$+$i$NCfCG(B(Abort)$B?.9f(B
       SIGFPE         8       C     $BIbF0>.?tE@Nc30(B
       SIGKILL        9      AEF    Kill$B%7%0%J%k(B
       SIGSEGV       11       C     $BITEv$J%a%b%j;2>H(B
       SIGPIPE       13       A     $B%Q%$%WGK2u(B: $BFI$_



 SIGQUIT, SIGILL: 
$B>e5-$O%^%K%e%"%k$+$i$NH4?h$G$"$k$,!$$b$H$N%^%K%e%"%k%Z!<%8$K0J2<$N4V0c$$$,$"$j!$(B
SIGQUIT, SIGILL$B$N%G%U%)%k%H$NF0:n$O!V%W%m%;%9$N=*N;$H%3%"%@%s%W!W$G$"$k!%(B
$B$7$+$7!$0J2<$N$h$&$K1Q8l$N%^%K%e%"%k%Z!<%8$K$O@5$7$$>pJs$,=P$F$$$k!%(B




       SIGQUIT       3        C      Quit from keyboard
       SIGILL        4        C      Illegal Instruction



$BF|K\8l$N%^%K%e%"%k%Z!<%8$N>pJs$O8E$+$C$?$j!$8mLu$G0UL#$,ITL@$G$"$C$?$j$9$k$3$H$,$"$k$?$a!$$=$N$h$&$J>l9g$O1Q8l$N%^%K%e%"%k%Z!<%8$r;2>H$9$Y$-$G$"$k!%(B
$B1Q8l$N%^%K%e%"%k%Z!<%8$O0J2<$N$h$&$K$9$k$HI=<($5$;$k$3$H$,$G$-$k!%(B


% env LANG=C man 7 signal


signal $B%7%9%F%`%3!<%k(B


signal $B%7%9%F%`%3!<%k$O!$%7%0%J%k$r%5%]!<%H$9$k$?$a$K:G=i$K:n$i$l$?%7%9%F%`%3!<%k$G$"$k!%(B


typedef void (*sighandler_t)(int);
sighandler_t signal(int signum, sighandler_t sighandler);



$B%7%0%J%k%O%s%I%i$rJQ99$9$k%7%0%J%k$H?7$7$$%7%0%J%k%O%s%I%i$r0z?t$K;XDj$7$F8F$S=P$9$H!$8E$$%7%0%J%k%O%s%I%i$,JV$5$l$k!%(B
signal $B%7%9%F%`%3!<%k$N0z?t$HLa$jCM$N7?$O(B sighandler_t $B$G$"$j!$$3$l$O(B int $B7?$r0z?t$K

void signal_handler(int);



$B8E$$%7%0%J%k%O%s%I%i$NCM$H$7$F$O
 SIG_IGN$B!!%7%0%J%k$NL5;k(B
 SIG_DFL$B!!%G%U%)%k%H$NF0:n(B





$B%7%0%J%k$H6&$K;H$o$l$k%7%9%F%`%3!<%k$K(B pause $B$,$"$k!%(B
pause $B$r8F$S=P$9$H%7%0%J%k$r

int pause(void);



$B0J2<$O(B signal $B$H(B pause $B$r;H$C$?%W%m%0%i%`Nc$G$"$k!%(B


 6$B!A(B20$B9TL\!'%7%0%J%k%O%s%I%i$NDj5A!%(B3$B2s5/F0$9$k$H(B exit $B$r8F$V!%(B
 24$B9TL\!'(BSIGINT$B$KBP$9$k%7%0%J%k%O%s%I%i$H$7$F(B sigint_handler $B$r@_Dj(B
 30$B9TL\!'(Bpause $B$G%7%0%J%k$r

$B$D$^$j!$(BCtrl-C $B$?$?$/EY$K(B sigint_handler $B$,5/F0$7!$(B3$B2s$?$?$/$H=*N;$9$k!%(B


     1  #include <stdio.h>
     2  #include <signal.h>
     3
     4  int sigint_count = 3;
     5
     6  void
     7  sigint_handler(int signum)
     8  {
     9          printf("sigint_handler(%d): sigint_count(%d)\n",
    10              signum, sigint_count);
    11
    12          if (--sigint_count <= 0) {
    13                  printf("sigint_handler: exiting ... \n");
    14                  exit(1);
    15          }
    16
    17  #if 0   /* For the original System V signal */
    18          signal(SIGINT, &sigint_handler);
    19  #endif
    20  }
    21
    22  main()
    23  {
    24          signal(SIGINT, &sigint_handler);
    25
    26          for (;;) {
    27                  printf("main: sigint_count(%d), calling pause ....\n",
    28                      sigint_count);
    29
    30                  pause();
    31
    32                  printf("main: return from pause. sigint_count(%d)\n",
    33                      sigint_count);
    34          }
    35  }



$B%3%s%Q%$%k!$

% ./a.out 
main: sigint_count(3), calling pause ....
sigint_handler(2): sigint_count(3)
main: return from pause. sigint_count(2)
main: sigint_count(2), calling pause ....
sigint_handler(2): sigint_count(2)
main: return from pause. sigint_count(1)
main: sigint_count(1), calling pause ....
sigint_handler(2): sigint_count(1)
sigint_handler: exiting ...
%



signal $B%7%9%F%`%3!<%k$N:G=i$N!J$7$+$7$J$,$i(B System V $B7O$N(B UNIX $B$^$G7Q>5$5$l$?!K;EMM$O!$B?$/$NLdBj$r;}$C$F$$$?!%(B


 $B%7%9%F%`%3!<%k$r8F$S=P$7%V%m%C%/$7$F$$$k;~$NF0:n!'(B


$BNc$($P(B read $B%7%9%F%`%3!<%k$r8F$S=P$7!$F~NOBT$A$N>uBV$G%V%m%C%/$7$F$$$k;~$K!$%7%0%J%k$,DLCN$5$l$?>l9g!$%7%0%J%k$O=hM}$5$l!$$=$N%7%0%J%k$KBP1~$9$k%7%0%J%k%O%s%I%i$,5/F0$5$l$k!%(B
$B$3$N>l9g!$%V%m%C%/>uBV$K$J$C$F$$$?%7%9%F%`%3!<%k$O%-%c%s%;%k$5$l(B EINTR $B$H$$$&%(%i!<$,JV$5$l$k$h$&$K$J$C$F$$$?!%(B


 $B%7%0%J%k%O%s%I%i$N%^%9%/$H%j%;%C%H!'(B


$B$"$k%7%0%J%k$KBP1~$7$?%7%0%J%k%O%s%I%i$rl9g!$F1$8%7%0%J%k%O%s%I%i$r5/F0$7$F$7$^$&$H!$%G!<%?$N0l4S@-$J$I$KLdBj$,@8$8$F$7$^$&!%(B
$B$=$N$?$a!$%7%0%J%k%O%s%I%i$O0lEY8F$S=P$5$l$k$H%G%U%)%k%H$NF0:n$K%j%;%C%H$5$l$k$h$&$K$J$C$F$$$?!%(B
$B$=$N$?$a!$%7%0%J%k%O%s%I%i$,5/F0$5$l$kEY$K(B signal $B%7%9%F%`%3!<%k$G%7%0%J%k%O%s%I%i$r@_Dj$7D>$9I,MW$,$"$C$?!J>e5-%W%m%0%i%`$N(B17$B!A(B19$B9TL\!K!%(B



$B$7$+$7$J$,$i!$$3$NJ}K!$G$O%G%U%)%k%H$NF0:n$,%W%m%;%9$N=*N;$G$"$C$?>l9g!$%7%0%J%k%O%s%I%i$r


$B$=$3$G%7%0%J%k$rL5;k$9$k$h$&$K%7%0%J%k%O%s%I%i$N@hF,$G(B SIG_IGN $B$r@_Dj$9$l$PNI$$$h$&$K;W$o$l$k$,$,!$$3$N>l9g$O(B

 $B%7%0%J%k%O%s%I%i$,5/F0$5$l(B signal $B%7%9%F%`%3!<%k$,8F$P$l(B SIG_IGN $B$,@_Dj$5$l$k$^$G$K$o$:$+$J$,$i7d4V$,$"$k(B
 $BDLCN$5$l$?%7%0%J%k$OL5;k$5$l$F$7$^$&$?$a!$$=$N%7%0%J%k$rBT$D$D$b$j$G(B pause $B$r8F$V$H1J1s$K%V%m%C%/$7$F$7$^$&!$(B

$B$H$$$&LdBj$,$"$k!%(B






System V $B$H$OJL$N7ONs$N(BUNIX$B$K(BBSD (Berkeley Software Distribution) $B$H$$$&$b$N$,$"$C$?!%(B
BSD UNIX$B$G$O>e5-$N$h$&$JLdBj$KBP$7(B signal $B$NF0:n$rJQ$($k$3$H$GBP1~$7$h$&$H$7$?!%(B


 $B%7%9%F%`%3!<%k$r8F$S=P$7%V%m%C%/$7$F$$$k;~$NF0:n!'(B


$B%7%9%F%`%3!<%k$O%-%c%s%;%k$5$l$J$$!%(B
$B%7%0%J%k%O%s%I%iuBV$KLa$k!K!%(B


 $B%7%0%J%k%O%s%I%i$N%^%9%/$H%j%;%C%H!'(B


$B%7%0%J%k%O%s%I%i$N



BSD UNIX$B$NJQ99$O5!G=$9$k$b$N$G$"$C$?$,!$(BSystem V UNIX $B$N8E$$(B signal $B$HF1$8(BAPI$B$rMQ$$$?$?$a!$:.Mp$N860x$H$J$C$?!%(B
Linux $B$O$I$A$i$+$H$$$&$H(B System V $B$N(BAPI$B$r;}$C$F$*$j=i4|$N%P!<%8%g%s$G$O8E$$(B signal $B$N(BAPI$B$rDs6!$7$F$$$?$,!$8=:_$O(BBSD UNIX$B$N(B signal $B$N(BAPI$B$rDs6!$7$F$$$k!%(B
$B$=$N$?$a>e5-%W%m%0%i%`$N(B17$B!A(B19$B9TL\$OITMW$K$J$C$F$$$k!%(B


sigaction $B%7%9%F%`%3!<%k(B


signal $B%7%9%F%`%3!<%k$N:.Mp>uBV$r2r7h$9$k$?$a$K!$(BPOSIX $B$G$O(B sigaction $B$H$$$&?7$7$$%7%9%F%`%3!<%k$rF3F~$7$?!%(B
sigaction $B$GF3F~$5$l$?%7%0%J%k$N$3$H$r!$5lMh$N%7%0%J%k%a%+%K%:%`$H6hJL$9$k$?$a$K(BPOSIX$B%7%0%J%k$H8F$P$l$k$3$H$,$"$k!%(B
POSIX$B=`5r$N%7%9%F%`$G$"$l$P(B sigaction $B$r;HMQ$9$Y$-$G$"$j!$(Bsignal $B$O$b$O$d;HMQ$9$Y$-$G$O$J$$!%(B


int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact);



sigaction $B%7%9%F%`%3!<%k$O!$Bh(B1$B0z?t$K%7%0%J%kHV9f!$Bh(B2$B0z?t$K@_Dj$9$k%7%0%J%k$NF0:n$r;XDj$7$F8F$S=P$9$H!$Bh(B3$B0z?t$K8E$$@_Dj$,JV$5$l$k!%(B



$B>e5-$NLdBjE@$K$*$1$k(BPOSIX$B%7%0%J%k$N%G%U%)%k%H$NF0:n$O
 $B%7%9%F%`%3!<%k$r8F$S=P$7%V%m%C%/$7$F$$$k;~$NF0:n!'(B


$B8E$$(B signal $B$HF1$8$/!$%7%9%F%`%3!<%k$O%-%c%s%;%k$5$l(B EINTR $B$H$$$&%(%i!<$,JV$5$l$k!%(B


 $B%7%0%J%k%O%s%I%i$N%^%9%/$H%j%;%C%H!'(B


$B$3$NE@$D$$$F$O(BBSD UNIX$B$HF1$8$G$k!%(B
$B%7%0%J%k%O%s%I%i$N



$B$I$A$i$NE@$K$D$$$F$b!$@_Dj$K$h$j8E$$(B signal $BKt$O(B BSD UNIX $B$NF0:n$r$5$;$k$3$H$,$G$-$k$h$&$K$J$C$F$$$k!%(B



$B%7%0%J%k$NF0:n$O0J2<$N(B struct sigaction $B$rMQ$$$F@_Dj$9$k!%(B


struct sigaction {
        void (*sa_handler)(int);
        void (*sa_sigaction)(int, siginfo_t *, void *);
        sigset_t sa_mask;
        int sa_flags;
        void (*sa_restorer)(void);
}




 sa_handler$B!!%7%0%J%k%O%s%I%i(B
 sa_sigaction$B!!$h$j>\$7$$%7%0%J%k>pJs$r0z?t$K sa_mask$B!!%7%0%J%k%O%s%I%i5/F0;~$K!$BP1~$9$k%7%0%J%k$NB>$K%^%9%/$7$?$$%7%0%J%k(B
 sa_flags$B!!F0:n$N>\:Y$r@_Dj$9$k%U%i%0(B
 sa_restorer$B!!%*%V%=%j!<%H!J;HMQ$7$F$O$$$1$J$$!K(B




$B8E$$(B signal $B$N%W%m%0%i%`$r!$(Bsigaction $B$G(B sa_handler $B$r;H$&$h$&$KJQ99$9$k$H(B$B0J2<(B$B$N$h$&$K$J$k!%(B
$B4pK\E*$K$OA4$/F1$8$G$"$k$,!$
 22$B9TL\!'%9%?%C%/>e$K 23$B9TL\!'%7%0%J%k%O%s%I%i$O(B sigint_handler
 24$B9TL\!'(Bsa_flags $B$K(B SA_RESTART $B$r@_Dj$7!$%7%0%J%k$K$h$jCfCG$5$l$?%7%9%F%`%3!<%k$N=hM}$O:F3+$9$k$h$&$K@_Dj(B
 26$B9TL\!'(Bsigaction $B$K$h$j%7%0%J%k$r@_Dj(B



     1  #include <stdio.h>
     2  #include <signal.h>
     3
     4  int sigint_count = 3;
     5
     6  void
     7  sigint_handler(int signum)
     8  {
     9          printf("sigint_handler(%d): sigint_count(%d)\n",
    10              signum, sigint_count);
    11
    12          if (--sigint_count <= 0) {
    13                  printf("sigint_handler: exiting ... \n");
    14                  exit(1);
    15          }
    16  }
    17
    18  main()
    19  {
    20          struct sigaction sa_sigint;
    21
    22          memset(&sa_sigint, 0, sizeof(sa_sigint));
    23          sa_sigint.sa_handler = sigint_handler;
    24          sa_sigint.sa_flags = SA_RESTART;
    25
    26          if (sigaction(SIGINT, &sa_sigint, NULL) < 0) {
    27                  perror("sigaction");
    28                  exit(1);
    29          }
    30
    31          for (;;) {
    32                  printf("main: sigint_count(%d), calling pause ....\n",
    33                      sigint_count);
    34
    35                  pause();
    36
    37                  printf("main: return from pause. sigint_count(%d)\n",
    38                      sigint_count);
    39          }
    40  }



$B>e5-%W%m%0%i%`$Nl9g$HF10l$G$"$k$N$G!$>JN,!%(B



$BF1$8%W%m%0%i%`$r!$(Bsigaction $B$G(B sa_sigaction $B$r;H$&$h$&$KJQ99$7$?%W%m%0%i%`$O0J2<$N$h$&$K$J$k!%(B


     1  #include <stdio.h>
     2  #include <signal.h>
     3  
     4  int sigint_count = 3;
     5  
     6  void
     7  sigint_action(int signum, siginfo_t *info, void *ctx)
     8  {
     9          printf("sigint_handler(%d): sigint_count(%d) signo(%d) code(0x%x)\n",
    10              signum, sigint_count, info->si_signo, info->si_code);
    11  
    12          if (--sigint_count <= 0) {
    13                  printf("sigint_handler: exiting ... \n");
    14                  exit(1);
    15          }
    16  }
    17  
    18  main()
    19  {
    20          struct sigaction sa_sigint;
    21  
    22          memset(&sa_sigint, 0, sizeof(sa_sigint));
    23          sa_sigint.sa_sigaction = sigint_action;
    24          sa_sigint.sa_flags = SA_RESTART | SA_SIGINFO;
    25  
    26          if (sigaction(SIGINT, &sa_sigint, NULL) < 0) {
    27                  perror("sigaction");
    28                  exit(1);
    29          }
    30  
    31          while (1) {
    32                  printf("main: sigint_count(%d), calling pause ....\n",
    33                      sigint_count );
    34  
    35                  pause();
    36  
    37                  printf("main: return from pause. sigint_count(%d)\n",
    38                      sigint_count );
    39          }
    40  }



$B%3%s%Q%$%k!$pJs$r0z?t$H$7$F\:Y$K$D$$$F$O(B SIGACTION(2) $B$r;2>H!%(B


% ./a.out 
main: sigint_count(3), calling pause ....
sigint_handler(2): sigint_count(3) signo(2) code(0x80)
main: return from pause. sigint_count(2)
main: sigint_count(2), calling pause ....
sigint_handler(2): sigint_count(2) signo(2) code(0x80)
main: return from pause. sigint_count(1)
main: sigint_count(1), calling pause ....
sigint_handler(2): sigint_count(1) signo(2) code(0x80)
sigint_handler: exiting ... 
%
$B%7%0%J%k$NL5;k(B

$Bl9g%7%0%J%k%O%s%I%i$K(B SIG_IGN $B$r@_Dj$9$k!%(B

     1  #include <stdio.h>
     2  #include <signal.h>
     3  
     4  int sigint_count = 3;
     5  
     6  main()
     7  {
     8          struct sigaction sa_ignore;
     9  
    10          memset(&sa_ignore, 0, sizeof(sa_ignore));
    11          sa_ignore.sa_handler = SIG_IGN;
    12  
    13          if (sigaction(SIGINT, &sa_ignore, NULL) < 0) {
    14                  perror("sigaction");
    15                  exit(1);
    16          }
    17  
    18          while (1) {
    19                  printf("main: sigint_count(%d), calling pause() ....\n",
    20                      sigint_count );
    21  
    22                  pause();
    23  
    24                  printf("main: return from pause().  sigint_count(%d)\n",
    25                      sigint_count );
    26          }
    27  }

$B%3%s%Q%$%k!$

% ./a.out 
main: sigint_count(3), calling pause() ....

Suspended
% jobs 
[1]  + Suspended                     ./a.out
% kill %1 
% 
[1]    Terminated                    ./a.out

$B0J2<$N$h$&$K!$(BSIG_IGN $B$NCM$O(B 1 $B$G$"$j!$$^$?%G%U%)%k%H$NF0:n$rI=$9(B SIG_DFL $B$NCM$O(B 0 $B$G$"$k!%(B sigaction $B$O8E$$@_Dj$rJV$9$,!$%7%0%J%k$rL5;k$^$?$O%G%U%)%k%H$N@_Dj$N>l9g$O!$$3$l$i$NCM$,(B sa_handler $B$KF~$C$F$/$k!%(B

#define SIG_DFL ((__sighandler_t) 0)            /* Default action.  */
#define SIG_IGN ((__sighandler_t) 1)            /* Ignore signal.  */

kill

$B%W%m%;%9$X%7%0%J%k$rAw$k$?$a$K$O(B kill $B%7%9%F%`%3!<%k$r;HMQ$9$k!%(B $B0z?t$KAw$j@h$N%W%m%;%9(BID$B$HAw$k%7%0%J%k$r;XDj$9$k!%(B

int kill(pid_t pid, int sig);

$B0J2<$O!$0z?t$K%W%m%;%9(BID$B$r;XDj$7!$$=$N%W%m%;%9$KBP$7(B SIGINT $B$rAw$k(B$B%W%m%0%i%`(B$B$G$"$k!%(B

     1  #include <stdio.h>
     2  #include <signal.h>
     3  #include <sys/types.h>
     4  
     5  main(int argc, char *argv[])
     6  {
     7          pid_t pid;
     8  
     9          if (argc != 2) {
    10                  printf("Usage: %s pid\n", argv[0]);
    11                  exit(1);
    12          }
    13  
    14          pid = atoi(argv[1]);
    15  
    16          if (pid <= 0) {
    17                  printf("Invalid pid: %d\n", pid);
    18                  exit(1);
    19          }
    20  
    21          if (kill(pid, SIGINT) < 0) {
    22                  perror("kill");
    23                  exit(1);
    24          }
    25  }

$B%$%s%?!<%P%k%?%$%^(B

$B$"$k0lDj;~4V$4$H$K3d$j9~$_$rH/@8$5$;!$8=:_$N=hM}$r7QB3$7$J$,$iJL$N=hM}!$Nc$($P%W%m%s%W%H$rE@LG$5$;$?$j!$%"%K%a!<%7%g%s$rl9g$K$O%$%s%?!<%P%k%?%$%^$H$$$&5!G=$r;HMQ$9$k!%(B $B%$%s%?!<%P%k%?%$%^$O(B setitimer $B%7%9%F%`%3!<%k$rMQ$$$F@_Dj$G$-$k!%(B

int setitimer(int which, const struct itimerval *value, struct itimerval *ovalue);

$B%$%s%?!<%P%k%?%$%^$OBh(B2$B0z?t$G;XDj$7$?;~4V$,7P$D!J;D$j;~4V$,(B 0 $B$K$J$k!K$H%7%0%J%k$GDLCN$9$k$,!$$I$N$h$&$J;~4V$J$N$+$r!$Bh(B1$B0z?t$N(B which $B$G0J2<$N%?%$%^!<$+$i(B1$B$D$r@_Dj$9$k!%(B

• ITIMER_REAL$B!!/$7!$;D$j;~4V$,(B 0 $B$K$J$C$?$i(B SIGALRM $B$,DLCN$5$l$k(B
• ITIMER_VIRTUAL$B!!%W%m%;%9$,%f!<%6%W%m%0%i%`$r/$7!$;D$j;~4V$,(B 0 $B$K$J$C$?$i(B SIGVALRM $B$,DLCN$5$l$k(B
• ITIMER_PROF$B!!%+!<%M%kFb$b4^$a$F%W%m%;%9$,/$7!$;D$j;~4V$,(B 0 $B$K$J$C$?$i(B SIGPROF $B$,DLCN$5$l$k(B

$BBh(B2$B0z?t$G;~4V$r;XDj$9$k$?$a$K;HMQ$9$k(B struct itimerval $B$H$=$NCf$G;H$o$l$F$$$k(B struct timeval $B$NDj5A$O0J2<$N$h$&$K$J$C$F$$$k!%(B

struct itimerval {
    struct timeval it_interval; /* next value */
    struct timeval it_value;    /* current value */
};

struct timeval {
    long tv_sec;                /* seconds */
    long tv_usec;               /* microseconds */
};

it_value $B$,(B 0 $B$K$J$k$H!$(Bwhich $B$G;XDj$5$l$k%?%$%^$KBP1~$9$k%7%0%J%k$,DLCN$5$l$k!%(B $B$=$7$F!$(Bit_interval $B$KCM$,

$B0J2<$O!$(BITIMER_REAL $B$G

     1  #include <stdio.h>
     2  #include <signal.h>
     3  #include <time.h>
     4  #include <sys/time.h>
     5  
     6  void alrm()
     7  {
     8          printf("alrm: %d\n", time(NULL));
     9  }
    10  
    11  main()
    12  {
    13          struct sigaction sa_alarm;
    14          struct itimerval itimer;
    15          int counter = 10;
    16  
    17          memset(&sa_alarm, 0, sizeof(sa_alarm));
    18          sa_alarm.sa_handler = alrm;
    19          sa_alarm.sa_flags = SA_RESTART;
    20  
    21          if (sigaction(SIGALRM, &sa_alarm, NULL) < 0) {
    22                  perror("sigaction");
    23                  exit(1);
    24          }
    25  
    26          itimer.it_value.tv_sec  = itimer.it_interval.tv_sec  = 1;
    27          itimer.it_value.tv_usec = itimer.it_interval.tv_usec = 0;
    28  
    29          if (setitimer(ITIMER_REAL, &itimer, NULL) < 0) {
    30                  perror("setitimer");
    31                  exit(1);
    32          }
    33  
    34          while (counter--) {
    35                  pause();
    36                  printf("main: %d\n", time(NULL));
    37          }
    38  }

$B%3%s%Q%$%k!$

% ./a.out 
alrm: 1115995143
main: 1115995143
alrm: 1115995144
main: 1115995144
alrm: 1115995145
main: 1115995145
alrm: 1115995146
main: 1115995146
alrm: 1115995147
main: 1115995147
alrm: 1115995148
main: 1115995148
alrm: 1115995149
main: 1115995149
alrm: 1115995150
main: 1115995150
alrm: 1115995151
main: 1115995151
alrm: 1115995152
main: 1115995152
%

$BN}=,LdBj(B

$BN}=,LdBj!J#4#2!K(B

kill $B%7%9%F%`%3!<%k$G%7%0%J%k$rAw$k(B$B%W%m%0%i%`(B$B$H%7%0%J%k$r$B%W%m%0%i%`(B$B$r;HMQ$7$F!$%W%m%;%9$+$i%W%m%;%9$X%7%0%J%k$,Aw$i$l$k$N$r3N$+$a$J$5$$!%(B

$B%R%s%H!'C

$BN}=,LdBj!J#4#3!K(B

$BJ#?t$N0[$J$k%7%0%J%k$KBP$7%7%0%J%k%O%s%I%i$r@_Dj$7!$%7%0%J%k$K1~$8$?%7%0%J%k%O%s%I%i$,5/F0$5$l$k$3$H$r3N$+$a$J$5$$!%(B

$BN}=,LdBj!J#4#4!K(B

$BIT@5$J%a%b%j%"%/%;%9$O(B SIGSEGV $B$K$h$jDLCN$5$l$k!%(B $B$I$N%"%I%l%9$KBP$7$F%"%/%;%9$,$"$C$?$N$+$rI=<($9$k%W%m%0%i%`$r:n@.$7$J$5$$!%(B

$B%R%s%H!'(BSIGACTION(2) $B$N(B siginfo_t $B$N>pJs$r;2>H!%(B

$BN}=,LdBj!J#4#5!K(B

sleep $B$O

$B%R%s%H!'(Bsetitimer, sigaction, pause $B$r;HMQ$9$k!%(B

$BN}=,LdBj!J#4#6!K(B

$B%-!<%\!<%I$+$i(B1$BJ8;zF~NO$rFI$_9~$`4X?t(B getchar $B$K%?%$%`%"%&%H5!G=$rDI2C$7$?4X?t(B mygetchar $B$r:n$j$J$5$$!%(B mygetchar $B$O!$$"$k0lDj;~4VFb$K%-!

$B%R%s%H!'(BSA_RESTART $B$O$I$&$$$&0UL#$+!)(B

$BN}=,LdBj!J#4#7!K(B

$BN}=,LdBj!J#2#9!K(B$B$HF1$8$h$&$K!$?F%W%m%;%9$H;R%W%m%;%9$,8r8_$KJ8;z$r=PNO$9$k%W%m%0%i%`$r!$%7%0%J%k$rMQ$$$F=q$-$J$5$$!%(B fork $B$G:n$k;R%W%m%;%9$O(B1$B$D$@$1$H$9$k!%(B