1 files changed, 96 insertions, 0 deletions
diff --git a/newlib/libc/stdlib/on_exit.c b/newlib/libc/stdlib/on_exit.c
new file mode 100644
index 000000000..1b6cd2abe
--- /dev/null
+++ b/newlib/libc/stdlib/on_exit.c
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 1990 Regents of the University of California.
+ * All rights reserved.
+ *
+ * %sccs.include.redist.c%
+ *
+ * This function is a modified version of atexit.c
+ */
+
+/*
+FUNCTION
+<<on_exit>>---request execution of function with argument at program exit
+
+INDEX
+	on_exit
+
+ANSI_SYNOPSIS
+	#include <stdlib.h>
+	int on_exit (void (*<[function]>)(int, void *), void *<[arg]>);
+
+TRAD_SYNOPSIS
+	#include <stdlib.h>
+	int on_exit ((<[function]>, <[arg]>)
+	  void (*<[function]>)(int, void *);
+	  void *<[arg]>;
+
+DESCRIPTION
+You can use <<on_exit>> to enroll functions in a list of functions that
+will be called when your program terminates normally.  The argument is
+a pointer to a user-defined function which takes two arguments.  The
+first is the status code passed to exit and the second argument is of type
+pointer to void.  The function must not return a result.  The value
+of <[arg]> is registered and passed as the argument to <[function]>.
+
+The functions are kept in a LIFO stack; that is, the last function
+enrolled by <<atexit>> or <<on_exit>> will be the first to execute when 
+your program exits.  You can intermix functions using <<atexit>> and
+<<on_exit>>.
+
+There is no built-in limit to the number of functions you can enroll
+in this list; however, after every group of 32 functions is enrolled,
+<<atexit>>/<<on_exit>> will call <<malloc>> to get space for the next part 
+of the list.   The initial list of 32 functions is statically allocated, so
+you can always count on at least that many slots available.
+
+RETURNS
+<<on_exit>> returns <<0>> if it succeeds in enrolling your function,
+<<-1>> if it fails (possible only if no space was available for
+<<malloc>> to extend the list of functions).
+
+PORTABILITY
+<<on_exit>> is a non-standard glibc extension
+
+Supporting OS subroutines required: None
+*/
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <reent.h>
+
+/*
+ * Register a function to be performed at exit.
+ */
+
+int
+_DEFUN (on_exit,
+	(fn, arg),
+	_VOID _EXFUN ((*fn), (int, _PTR)) _AND
+        _PTR arg)
+{
+  register struct _atexit *p;
+  void (*x)(void) = (void (*)(void))fn;
+
+/* _REENT_SMALL on_exit() doesn't allow more than the required 32 entries.  */
+#ifndef _REENT_SMALL
+  if ((p = _REENT->_atexit) == NULL)
+    _REENT->_atexit = p = &_REENT->_atexit0;
+  if (p->_ind >= _ATEXIT_SIZE)
+    {
+      if ((p = (struct _atexit *) malloc (sizeof *p)) == NULL)
+	return -1;
+      p->_ind = 0;
+      p->_fntypes = 0;
+      p->_next = _REENT->_atexit;
+      _REENT->_atexit = p;
+    }
+#else
+  p = &_REENT->_atexit;
+  if (p->_ind >= _ATEXIT_SIZE)
+    return -1;
+#endif
+  p->_fntypes |= (1 << p->_ind);
+  p->_fnargs[p->_ind] = arg;
+  p->_fns[p->_ind++] = x;
+  return 0;
+}