From: Tanaka Akira <akr@...17n.org>
Date: 2000-11-26T15:41:14+09:00
Subject: [ruby-list:26176] Re: fork problem?

In article <200011252247.HAA09258@sharui.nakada.kanuma.tochigi.jp>,
  nobu.nakada@nifty.ne.jp writes:

> > fork$B$H(Bthread$B$r:.$<$k$N$O$+$J$jLdBj$N85$G$9!#(B
> > $B$$$C$=!"(Bfork_and_kill_other_threads$B$r(Bfork$B$NI8=`;EMM$K$7$A$c(B
> > $B$$$^$7$g$&$+!#(B
> 
> $B!!$H$$$&$+!"(Bfork $B$9$k0JA0$N(B thread $B$,?7$7$$%W%m%;%96u4V$G$^$GF0(B
> $B$$$F$/$l$F4r$7$$>u67$H$$$&$N$,!"$A$g$C$HA[A|$D$+$J$+$C$?$s$G$9(B
> $B$,!#(Bfork $B$7$?;~E@$G$=$N(B thread $B$,(B main $B$K$J$C$F$=$l0J30$OB8:_$7(B
> $B$J$$!"$H$$$&$N$G$I$&$G$7$g$&$+!#(B

$B$=$l$,(B fork_and_kill_other_threads $B$N0U?^$G$9!#(B
($B=q$/$N$rK:$l$F$$$?$N$GDI5-$7$F$*$-$^$9$,!";&$9$N$O;R%W%m%;%9B&$G$NOC(B
$B$G!"?F%W%m%;%9B&$G$OEvA3!"F0$$$?$^$^$G$9!#(B)

$B$9$3$79M$($?$N$G$9$,!"%W%m%;%930$H$NDL?.$r9T$J$C$F$$$k(B thread $B$,(B fork
$B$GJ#@=$5$l$k$HLdBj$K$J$j$,$A$G$"$k!"$H$$$&$N$O3N$+$@$H;W$$$^$9!#(B

# $BNc30$b$"$k$h$&$J5$$b$7$^$9$,!#(Baccept $B$7$F$O(B Thread.new $B$9$k$@$1$N(B
# loop $B$H$+!#(B

$B$G!"5?Ld$J$N$O%W%m%;%930$H$NDL?.$r(B($BD>@\$K$O(B)$B9T$J$o$J$$(B thread $B$K$D$$$F(B
$B$G$9!#(Bthread $B%W%m%0%i%_%s%0$OAG?M(B($B$8$D$O:#2s=i$a$F(B thread $B$r;H$C$?(B)$B$J(B
$B$N$G$h$/$o$+$i$J$$$N$G$9$,!"$=$&$$$&$b$N$O(B fork $B;~$K$I$N$h$&$J?6Iq$r<((B
$B$9$N$,E,@Z$J$3$H$,B?$$$s$G$7$g$&$+(B? $B$=$l$H$b$=$s$J(B thread $B$OIaDL;H$o$l(B
$B$J$$(B?

$B$A$J$_$K!"(BThe Single UNIX (R) Specification, Version 2 $B$rD4$Y$F$_$k$H!"(B
fork(2) $B$O$^$5$K(B fork_and_kill_other_threads $B$N$h$&$JF0:n$r$9$k$h$&$G(B
$B$9!#(B

    A process is created with a single thread. If a multi-threaded process
    calls fork(), the new process contains a replica of the calling thread and
    its entire address space, possibly including the states of mutexes and
    other resources. Consequently, to avoid errors, the child process may only
    execute async-signal safe operations until such time as one of the exec
    functions is called. Fork handlers may be established by means of the
    pthread_atfork() function in order to maintain application invariants
    across fork() calls.

$B$=$7$F!"FCJL$J$3$H$r$7$?$$>l9g$K$O(B pthread_atfork $B$G(B fork $B;~$K<B9T$5$l(B
$B$k(B 3$B<oN`(B(fork $BA0!"(Bfork $B8e$N?F!"(Bfork $B8e$N;R(B)$B$N=hM}$r@_Dj$G$-$k$h$&$G$9!#(B
-- 
[$BEDCf(B $BE/(B][$B$?$J$+(B $B$"$-$i(B][Tanaka Akira]
$B!V$/$C$@$i$J$$%3%HJ9$$$A$c$C$?$M!<$(C"=(B $B$4$C$a!<$s$(C"=$B!W(B
  ($BKbK!;H$$M\@.@lLg(B $B%^%8%C%/%9%?!<3X1!(B 2, $BFn_7%_%E%-(B)