From 9bd926ee88340fe234e4e76d082658a909b24884 Mon Sep 17 00:00:00 2001
From: dave <dave@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Sat, 27 Dec 2003 16:07:43 +0000
Subject: RDoc comments added by Elliott Hughes

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@5321 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 signal.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)

(limited to 'signal.c')

diff --git a/signal.c b/signal.c
index 155f52a853..3bc2c7f7a2 100644
--- a/signal.c
+++ b/signal.c
@@ -643,6 +643,34 @@ rb_trap_restore_mask()
 #endif
 }
 
+/*
+ * call-seq:
+ *   Signal.trap( signal, proc ) => obj
+ *   Signal.trap( signal ) {| | block } => obj
+ *
+ * Specifies the handling of signals. The first parameter is a signal
+ * name (a string such as ``SIGALRM'', ``SIGUSR1'', and so on) or a
+ * signal number. The characters ``SIG'' may be omitted from the
+ * signal name. The command or block specifies code to be run when the
+ * signal is raised. If the command is the string ``IGNORE'' or
+ * ``SIG_IGN'', the signal will be ignored. If the command is
+ * ``DEFAULT'' or ``SIG_DFL'', the operating system's default handler
+ * will be invoked. If the command is ``EXIT'', the script will be
+ * terminated by the signal. Otherwise, the given command or block
+ * will be run.
+ * The special signal name ``EXIT'' or signal number zero will be
+ * invoked just prior to program termination.
+ * trap returns the previous handler for the given signal.
+ *
+ *     Signal.trap(0, proc { puts "Terminating: #{$$}" })
+ *     Signal.trap("CLD")  { puts "Child died" }
+ *     fork && Process.wait
+ *
+ * produces:
+ *     Terminating: 27461
+ *     Child died
+ *     Terminating: 27460
+ */
 static VALUE
 sig_trap(argc, argv)
     int argc;
@@ -681,6 +709,15 @@ sig_trap(argc, argv)
 #endif
 }
 
+/*
+ * call-seq:
+ *   Signal.list => a_hash
+ *
+ * Returns a list of signal names mapped to the corresponding
+ * underlying signal numbers.
+ *
+ * Signal.list   #=> {"ABRT"=>6, "ALRM"=>14, "BUS"=>7, "CHLD"=>17, "CLD"=>17, "CONT"=>18, "FPE"=>8, "HUP"=>1, "ILL"=>4, "INT"=>2, "IO"=>29, "IOT"=>6, "KILL"=>9, "PIPE"=>13, "POLL"=>29, "PROF"=>27, "PWR"=>30, "QUIT"=>3, "SEGV"=>11, "STOP"=>19, "SYS"=>31, "TERM"=>15, "TRAP"=>5, "TSTP"=>20, "TTIN"=>21, "TTOU"=>22, "URG"=>23, "USR1"=>10, "USR2"=>12, "VTALRM"=>26, "WINCH"=>28, "XCPU"=>24, "XFSZ"=>25}
+ */
 static VALUE
 sig_list()
 {
@@ -748,6 +785,43 @@ init_sigchld(sig)
 #endif
 }
 
+/*
+ * Many operating systems allow signals to be sent to running
+ * processes. Some signals have a defined effect on the process, while
+ * others may be trapped at the code level and acted upon. For
+ * example, your process may trap the USR1 signal and use it to toggle
+ * debugging, and may use TERM to initiate a controlled shutdown.
+ *
+ *     pid = fork do
+ *       Signal.trap("USR1") do
+ *         $debug = !$debug
+ *         puts "Debug now: #$debug"
+ *       end
+ *       Signal.trap("TERM") do
+ *         puts "Terminating..."
+ *         shutdown()
+ *       end
+ *       # . . . do some work . . .
+ *     end
+ *
+ *     Process.detach(pid)
+ *
+ *     # Controlling program:
+ *     Process.kill("USR1", pid)
+ *     # ...
+ *     Process.kill("USR1", pid)
+ *     # ...
+ *     Process.kill("TERM", pid)
+ *
+ * produces:
+ *     Debug now: true
+ *     Debug now: false
+ *    Terminating...
+ *
+ * The list of available signal names and their interpretation is
+ * system dependent. Signal delivery semantics may also vary between
+ * systems; in particular signal delivery may not always be reliable.
+ */
 void
 Init_signal()
 {
-- 
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