__gnat_error_handler for LynxOS in init.c only accepts a "sig" argument.
Add some comments to explain why, and how to fix it with a change to a
kernel build parameter.
Tested on x86_64-pc-linux-gnu, committed on trunk
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
--- 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)
{
