libgfortran/runtime/main.c

   1 /* Copyright (C) 2002-2017 Free Software Foundation, Inc.
   2    Contributed by Andy Vaught and Paul Brook <paul@nowt.org>
   3
   4 This file is part of the GNU Fortran runtime library (libgfortran).
   5
   6 Libgfortran is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 Libgfortran is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 Under Section 7 of GPL version 3, you are granted additional
  17 permissions described in the GCC Runtime Library Exception, version
  18 3.1, as published by the Free Software Foundation.
  19
  20 You should have received a copy of the GNU General Public License and
  21 a copy of the GCC Runtime Library Exception along with this program;
  22 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 <http://www.gnu.org/licenses/>.  */
  24
  25 #include "libgfortran.h"
  26
  27
  28 /* Stupid function to be sure the constructor is always linked in, even
  29    in the case of static linking.  See PR libfortran/22298 for details.  */
  30 void
  31 stupid_function_name_for_static_linking (void)
  32 {
  33   return;
  34 }
  35
  36 /* This will be 0 for little-endian
  37    machines and 1 for big-endian machines.  */
  38 int big_endian = 0;
  39
  40
  41 /* Figure out endianness for this machine.  */
  42
  43 static void
  44 determine_endianness (void)
  45 {
  46   union
  47   {
  48     GFC_LOGICAL_8 l8;
  49     GFC_LOGICAL_4 l4[2];
  50   } u;
  51
  52   u.l8 = 1;
  53   if (u.l4[0])
  54     big_endian = 0;
  55   else if (u.l4[1])
  56     big_endian = 1;
  57   else
  58     runtime_error ("Unable to determine machine endianness");
  59 }
  60
  61
  62 static int argc_save;
  63 static char **argv_save;
  64
  65
  66 /* Set the saved values of the command line arguments.  */
  67
  68 void
  69 set_args (int argc, char **argv)
  70 {
  71   argc_save = argc;
  72   argv_save = argv;
  73 }
  74 iexport(set_args);
  75
  76
  77 /* Retrieve the saved values of the command line arguments.  */
  78
  79 void
  80 get_args (int *argc, char ***argv)
  81 {
  82   *argc = argc_save;
  83   *argv = argv_save;
  84 }
  85
  86
  87 /* Initialize the runtime library.  */
  88
  89 static void __attribute__((constructor))
  90 init (void)
  91 {
  92   /* Figure out the machine endianness.  */
  93   determine_endianness ();
  94
  95   /* Must be first */
  96   init_variables ();
  97
  98   init_units ();
  99
 100   /* If (and only if) the user asked for it, set up the FPU state.  */
 101   if (options.fpe != 0)
 102     set_fpu ();
 103
 104   init_compile_options ();
 105 }
 106
 107
 108 /* Cleanup the runtime library.  */
 109
 110 static void __attribute__((destructor))
 111 cleanup (void)
 112 {
 113   close_units ();
 114 }