4.11.1 atexit.c

/* Copyright (c) 2013  Embecosm
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   AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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#include <stdlib.h>

#ifndef __DOXYGEN__
static struct atexit_s
{
  void (*fun) (void);
  struct atexit_s *next;
} *atexit_p;
#endif

int
atexit (void (*fun) (void))
{
  struct atexit_s *new_as = (struct atexit_s *) malloc (sizeof *new_as);
  if (!new_as)
    return 1;
  new_as->fun = fun;
  new_as->next = atexit_p;
  atexit_p = new_as;
  return 0;
}

#ifndef __DOXYGEN__
/* Don't inline this code as naked to arrange for the very unlikely case
   that it needs a frame.   This won't work as naked function.  */

static void __attribute__((__noinline__))
atexit_finido (void)
{
  while (atexit_p)
    {
      void (*fun) (void) = atexit_p->fun;
      atexit_p = atexit_p->next;
      (*fun) ();
    }
}

/* Run functions registered by atexit in .fini8 so that they are
   sequenced before static destructors which run in .fini6.  */

static void __attribute__((__naked__, __used__, __section__(".fini8")))
atexit_fini (void)
{
  atexit_finido ();
}
#endif  /* !__DOXYGEN__ */