dlfcn/dlsym.c

   1 /* Look up a symbol in a shared object loaded by `dlopen'.
   2    Copyright (C) 1995, 1996, 1997, 1998, 1999 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 #include <dlfcn.h>
  21 #include <stddef.h>
  22
  23 struct dlsym_args
  24 {
  25   /* The arguments to dlsym_doit.  */
  26   void *handle;
  27   const char *name;
  28   void *who;
  29
  30   /* The return value of dlsym_doit.  */
  31   void *sym;
  32 };
  33
  34 static void
  35 dlsym_doit (void *a)
  36 {
  37   struct dlsym_args *args = (struct dlsym_args *) a;
  38
  39   args->sym = _dl_sym (args->handle, args->name, args->who);
  40 }
  41
  42
  43 void *
  44 dlsym (void *handle, const char *name)
  45 {
  46   struct dlsym_args args;
  47   args.who = __builtin_return_address (0);
  48   args.handle = handle;
  49   args.name = name;
  50
  51   return (_dlerror_run (dlsym_doit, &args) ? NULL : args.sym);
  52 }