[pure-lang-svn] SF.net SVN: pure-lang:[479] pure/trunk

[<ag...@us...>]

Revision: 479
          http://pure-lang.svn.sourceforge.net/pure-lang/?rev=479&view=rev
Author:   agraef
Date:     2008-08-13 01:07:48 +0000 (Wed, 13 Aug 2008)

Log Message:
-----------
Add signal processing example.

Modified Paths:
--------------
    pure/trunk/ChangeLog

Added Paths:
-----------
    pure/trunk/examples/signal.pure

Modified: pure/trunk/ChangeLog
===================================================================
--- pure/trunk/ChangeLog	2008-08-12 23:58:36 UTC (rev 478)
+++ pure/trunk/ChangeLog	2008-08-13 01:07:48 UTC (rev 479)
@@ -1,5 +1,7 @@
 2008-08-13  Albert Graef  <Dr....@t-...>
 
+	* examples/signal.pure: Add signal processing example.
+
 	* runtime.cc (pure_catch, pure_invoke): Collecting temporary
 	values after an exception doesn't seem to be safe while an
 	evaluation is still in progress. Moved this to doeval/dodefn in

Added: pure/trunk/examples/signal.pure
===================================================================
--- pure/trunk/examples/signal.pure	                        (rev 0)
+++ pure/trunk/examples/signal.pure	2008-08-13 01:07:48 UTC (rev 479)
@@ -0,0 +1,30 @@
+
+/* Signal processing example. */
+
+using system;
+extern int getpid();
+
+/* The common POSIX termination signals like SIGHUP, SIGINT, SIGTERM etc. are
+   already remapped to Pure exceptions by the interpreter when it starts.
+   Other kinds of signals can be handled as Pure exceptions, too, if we rebind
+   them with the 'trap' function. (Try 'list -g SIG*' to see which standard
+   signal values are known on your system.) Example: */
+
+trap SIG_TRAP SIGTSTP;
+
+/* Running this function enters an endless loop reporting all signals
+   delivered to the process. */
+
+test = printf "Running as pid %d, try to kill me!\n" getpid, loop;
+
+loop = loop when _ = catch sig check end
+with
+  sig (signal k) = loop when _ = printf "Hey, I got signal %d.\n" k end;
+end;
+
+/* Take a short nap so that the loop doesn't run busily. This also serves the
+   purpose of checking for pending signals. (Note that for performance reasons
+   the Pure interpreter only processes asynchronous signals at certain points,
+   such as the entry of a global Pure function.) */
+
+check = sleep 1;


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