From: Simon Marlow <simonmar@microsoft.com>
Date: Thu, 6 Apr 2006 14:48:36 +0000 (+0000)
Subject: Add SA_RESTART flag to the timer signal handler.
X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=1494f895d69a33df2f8d855f73943faec5c6858e;hp=d7d596d039b48dec6b71df9c4bca0d12958ecdb9

Add SA_RESTART flag to the timer signal handler.
This seems to be necessary to prevent readline being confused by our
SIGALRM handler.
---

diff --git a/ghc/rts/posix/Itimer.c b/ghc/rts/posix/Itimer.c
index 06d0e6c..83ed84d 100644
--- a/ghc/rts/posix/Itimer.c
+++ b/ghc/rts/posix/Itimer.c
@@ -84,7 +84,18 @@ install_vtalrm_handler(TickProc handle_tick)
     action.sa_handler = handle_tick;
 
     sigemptyset(&action.sa_mask);
+
+#ifdef SA_RESTART
+    // specify SA_RESTART.  One consequence if we don't do this is
+    // that readline gets confused by the -threaded RTS.  It seems
+    // that if a SIGALRM handler is installed without SA_RESTART,
+    // readline installs its own SIGALRM signal handler (see
+    // readline's signals.c), and this somehow causes readline to go
+    // wrong when the input exceeds a single line (try it).
+    action.sa_flags = SA_RESTART;
+#else
     action.sa_flags = 0;
+#endif
 
     return sigaction(ITIMER_SIGNAL, &action, NULL);
 }