From: Doug Rupp <rupp@adacore.com>
Date: Wed, 7 Jul 2021 16:38:34 +0000 (-0700)
Subject: [Ada] Add some comments in init.c about the lynx178 signal handler
X-Git-Tag: upstream/12.2.0~4941
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=303b5d874720aa1830c696a20e1e03abc1a12e14;p=platform%2Fupstream%2Fgcc.git

[Ada] Add some comments in init.c about the lynx178 signal handler

gcc/ada/

	* init.c (__gnat_error_handler) [LynxOS]: Add a comment about
	missing optional args.
---

diff --git a/gcc/ada/init.c b/gcc/ada/init.c
index c48e244..2bbb601 100644
--- a/gcc/ada/init.c
+++ b/gcc/ada/init.c
@@ -661,6 +661,28 @@ __gnat_install_handler (void)
 #include <signal.h>
 #include <unistd.h>
 
+/* SA_SIGINFO is not supported by default on LynxOS, so all we have
+   available here is the "sig" argument. On newer LynxOS versions it's
+   possible to support SA_SIGINFO by setting a kernel configuration macro.
+
+   To wit:
+
+   #define NONPOSIX_SA_HANDLER_PROTO (0)
+
+   This macro must be set to 1 in either sys/bsp.<bspname>/uparam.h
+   or in the associated uparam.h customization file sys/bsp.<bspname>/xparam.h
+   (uparam.h includes xparam.h for customization)
+
+   The NONPOSIX_SA_HANDLER_PROTO macro makes it possible to provide
+   signal-catching function with 'info' and 'context' input parameters
+   even if SA_SIGINFO flag is not set or it is set for a non-realtime signal.
+
+   It also allows signal-catching function to update thread context even
+   if SA_UPDATECTX flag is not set.
+
+   This would be useful, but relying on that would transmit the requirement
+   to users to configure that feature as well, which is undesirable.  */
+
 static void
 __gnat_error_handler (int sig)
 {