From cd13c99d23979c731a447058cf126015a5e739c2 Mon Sep 17 00:00:00 2001
From: sbund <sbund@wiback.org>
Date: Thu, 7 Sep 2006 08:31:39 +0000
Subject: [PATCH] Added some comments concerning future enhancements
---
Scheduler/Scheduler.cc | 43 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/Scheduler/Scheduler.cc b/Scheduler/Scheduler.cc
index 257e5f617..21885f24a 100644
--- a/Scheduler/Scheduler.cc
+++ b/Scheduler/Scheduler.cc
@@ -20,6 +20,48 @@
// Free Software Foundation, Inc.,
// 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+// TODO: Implement signal handling
+// Here a basic concept of how to add signal support to the scheduler:
+//
+// Every signal to be reported by the scheduler will be asigned a
+// generic signal handler by the scheduler. This signal handler will
+// use longjmp (juck) to report this signal back to the scheduler
+// main-loop.
+//
+// To make this safe, the main-loop will look something like:
+//
+// int signal = setjmp(jmpBuffer_);
+// if (signal == 0) {
+// // unblock all signals which are registered with the
+// // scheduler
+// // call epoll
+// // block all relevant signals again
+// }
+//
+// // now handle the event
+//
+// The signal handler is then simply defined as
+//
+// static void Scheduler::sigHandler(int signal)
+// {
+// // make sure to restore the signal handler here if
+// // necessary
+// longjmp(Scheduler::instance().jmpBuffer_,signal);
+// }
+//
+// You should use sigaction to register the signal handlers and define
+// a sa_mask so all Scheduler-registered signals are automatically
+// *blocked* whenever one of the signals is called (including the
+// called signal!). This ensures, that no two signals can be delivered
+// on top of each other. And of course any signal registered with the
+// scheduler must be blocked as soon as it is registered with the
+// scheduler.
+
+// TODO: Multithreading support
+// To support multithreading, the static member Scheduler::instance()
+// must return a thread-local value (that is Scheduler::instance()
+// must allocate one Scheduler instance per thread)
+
// Definition of non-inline non-template functions
#include "Scheduler.hh"
@@ -118,6 +160,7 @@ prefix_ void satcom::lib::Scheduler::process()
struct epoll_event ev;
int events = epoll_wait(epollFd_, &ev, 1, 1000);
if (events<0)
+ // Hmm ... man epoll says, it will NOT return with EINTR ??
throw SystemException(errno);
if (events==0)
continue;
--
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