From 1e166f7ecbddc2e59005d9b17a967c57d7331a8a Mon Sep 17 00:00:00 2001
From: Xiang Xiao <xiaoxiang@xiaomi.com>
Date: Mon, 22 Jun 2020 12:37:37 +0800
Subject: [PATCH] sysconf: Implement _SC_ATEXIT_MAX query

and remove the incorrect macro ATEXIT_MAX

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Ia5d7dafc50e942f62f95137313c34741c6dd60ba
---
 include/unistd.h               | 6 ------
 libs/libc/unistd/lib_sysconf.c | 8 ++++++++
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/unistd.h b/include/unistd.h
index 0d4283a117..e51ab9fc3e 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -48,12 +48,6 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
-/* The number of functions that may be registered to be called
- * at program exit.
- */
-
-#define ATEXIT_MAX 1
-
 /* Values for seeking */
 
 #define SEEK_SET    0  /* From the start of the file */
diff --git a/libs/libc/unistd/lib_sysconf.c b/libs/libc/unistd/lib_sysconf.c
index 7f51d9e99e..c27acf740e 100644
--- a/libs/libc/unistd/lib_sysconf.c
+++ b/libs/libc/unistd/lib_sysconf.c
@@ -41,6 +41,7 @@
 #include <nuttx/config.h>
 
 #include <unistd.h>
+#include <sched.h>
 #include <errno.h>
 
 /****************************************************************************
@@ -225,6 +226,13 @@ long sysconf(int name)
       case _SC_OPEN_MAX:
         return CONFIG_NFILE_DESCRIPTORS;
 
+      case _SC_ATEXIT_MAX:
+#ifdef CONFIG_SCHED_EXIT_MAX
+        return CONFIG_SCHED_EXIT_MAX;
+#else
+        return 0;
+#endif
+
       default:
 #if 0 /* Assume valid but not implemented for the time being */
         errcode = EINVAL;