sysdeps/unix/sysv/linux/init-first.h

   1 /* Prepare arguments for library initialization function.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 /* The job of this fragment it to find argc and friends for INIT.
  21    This is done in one of two ways: either in the stack context
  22    of program start, or having dlopen pass them in.  */
  23
  24 #define SYSDEP_CALL_INIT(NAME, INIT)                                          \
  25 void NAME (void *arg)                                                         \
  26 {                                                                             \
  27   int argc;                                                                   \
  28   char **argv, **envp;                                                        \
  29   /* The next variable is only here to work around a bug in gcc <= 2.7.2.2.   \
  30      If the address would be taken inside the expression the optimizer        \
  31      would try to be too smart and throws it away.  Grrr.  */                 \
  32   int *dummy_addr = &_dl_starting_up;                                         \
  33                                                                               \
  34   __libc_multiple_libcs = dummy_addr && !_dl_starting_up;                     \
  35                                                                               \
  36   if (!__libc_multiple_libcs)                                                 \
  37     {                                                                         \
  38       argc = (int) arg;                                                       \
  39       argv = (char **) &arg + 1;                                              \
  40       envp = &argv[argc+1];                                                   \
  41     }                                                                         \
  42   else                                                                        \
  43     {                                                                         \
  44       argc = (int) arg;                                                       \
  45       argv = ((char ***) &arg)[1];                                            \
  46       envp = ((char ***) &arg)[2];                                            \
  47     }                                                                         \
  48                                                                               \
  49   INIT (argc, argv, envp);                                                    \
  50 }