bits/dlfcn.h

   1 /* System dependent definitions for run-time dynamic loading.
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000 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 #ifndef _DLFCN_H
  21 # error "Never use <bits/dlfcn.h> directly; include <dlfcn.h> instead."
  22 #endif
  23
  24 /* The MODE argument to `dlopen' contains one of the following: */
  25 #define RTLD_LAZY       0x001   /* Lazy function call binding.  */
  26 #define RTLD_NOW        0x002   /* Immediate function call binding.  */
  27 #define RTLD_BINDING_MASK 0x3   /* Mask of binding time value.  */
  28
  29 /* If the following bit is set in the MODE argument to `dlopen',
  30    the symbols of the loaded object and its dependencies are made
  31    visible as if the object were linked directly into the program.  */
  32 #define RTLD_GLOBAL     0x100
  33
  34 /* Unix98 demands the following flag which is the inverse to RTLD_GLOBAL.
  35    The implementation does this by default and so we can define the
  36    value to zero.  */
  37 #define RTLD_LOCAL      0
  38
  39 #ifdef __USE_GNU
  40 /* To support profiling of shared objects it is a good idea to call
  41    the function found using `dlsym' using the following macro since
  42    these calls do not use the PLT.  But this would mean the dynamic
  43    loader has no chance to find out when the function is called.  The
  44    macro applies the necessary magic so that profiling is possible.
  45    Rewrite
  46         foo = (*fctp) (arg1, arg2);
  47    into
  48         foo = DL_CALL_FCT (fctp, (arg1, arg2));
  49 */
  50 # define DL_CALL_FCT(fctp, args) \
  51   (_dl_mcount_wrapper_check (fctp), (*(fctp)) args)
  52
  53 /* This function calls the profiling functions.  */
  54 extern void _dl_mcount_wrapper_check (void *__selfpc) __THROW;
  55 #endif