bits/dlfcn.h

   1 /* System dependent definitions for run-time dynamic loading.
   2    Copyright (C) 1996-2016 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _DLFCN_H
  20 # error "Never use <bits/dlfcn.h> directly; include <dlfcn.h> instead."
  21 #endif
  22
  23 /* The MODE argument to `dlopen' contains one of the following: */
  24 #define RTLD_LAZY       0x00001 /* Lazy function call binding.  */
  25 #define RTLD_NOW        0x00002 /* Immediate function call binding.  */
  26 #define RTLD_BINDING_MASK   0x3 /* Mask of binding time value.  */
  27 #define RTLD_NOLOAD     0x00004 /* Do not load the object.  */
  28 #define RTLD_DEEPBIND   0x00008 /* Use deep binding.  */
  29
  30 /* If the following bit is set in the MODE argument to `dlopen',
  31    the symbols of the loaded object and its dependencies are made
  32    visible as if the object were linked directly into the program.  */
  33 #define RTLD_GLOBAL     0x00100
  34
  35 /* Unix98 demands the following flag which is the inverse to RTLD_GLOBAL.
  36    The implementation does this by default and so we can define the
  37    value to zero.  */
  38 #define RTLD_LOCAL      0
  39
  40 /* Do not delete object when closed.  */
  41 #define RTLD_NODELETE   0x01000
  42
  43 #ifdef __USE_GNU
  44 /* To support profiling of shared objects it is a good idea to call
  45    the function found using `dlsym' using the following macro since
  46    these calls do not use the PLT.  But this would mean the dynamic
  47    loader has no chance to find out when the function is called.  The
  48    macro applies the necessary magic so that profiling is possible.
  49    Rewrite
  50         foo = (*fctp) (arg1, arg2);
  51    into
  52         foo = DL_CALL_FCT (fctp, (arg1, arg2));
  53 */
  54 # define DL_CALL_FCT(fctp, args) \
  55   (_dl_mcount_wrapper_check ((void *) (fctp)), (*(fctp)) args)
  56
  57 __BEGIN_DECLS
  58
  59 /* This function calls the profiling functions.  */
  60 extern void _dl_mcount_wrapper_check (void *__selfpc) __THROW;
  61
  62 __END_DECLS
  63
  64 #endif