elf/dlfcn.h

   1 /* dlfcn.h -- User functions for run-time dynamic loading.
   2    Copyright (C) 1995, 1996 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
  22 #define _DLFCN_H 1
  23 #include <features.h>
  24
  25 /* The MODE argument to `dlopen' contains one of the following: */
  26 #define RTLD_LAZY       0x001   /* Lazy function call binding.  */
  27 #define RTLD_NOW        0x002   /* Immediate function call binding.  */
  28 #define RTLD_BINDING_MASK 0x3   /* Mask of binding time value.  */
  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     0x100
  34
  35 /* If the first argument of `dlsym' is set to RTLD_NEXT the run-time
  36    address of the symbol called NAME in the next shared object is
  37    returned.  The "next" relation is defined by the order the shared
  38    objects were loaded.  */
  39 #define RTLD_NEXT       ((void *) -1l)
  40
  41 __BEGIN_DECLS
  42
  43 /* Open the shared object FILE and map it in; return a handle that can be
  44    passed to `dlsym' to get symbol values from it.  */
  45 extern void *dlopen __P ((__const char *__file, int __mode));
  46
  47 /* Unmap and close a shared object opened by `dlopen'.
  48    The handle cannot be used again after calling `dlclose'.  */
  49 extern int dlclose __P ((void *__handle));
  50
  51 /* Find the run-time address in the shared object HANDLE refers to
  52    of the symbol called NAME.  */
  53 extern void *dlsym __P ((void *__handle, __const char *__name));
  54
  55 /* When any of the above functions fails, call this function
  56    to return a string describing the error.  Each call resets
  57    the error string so that a following call returns null.  */
  58 extern char *dlerror __P ((void));
  59
  60 /* Fill in *INFO with the following information about ADDRESS.
  61    Returns 0 iff no shared object's segments contain that address.  */
  62 typedef struct
  63   {
  64     __const char *dli_fname;    /* File name of defining object.  */
  65     void *dli_fbase;            /* Load address of that object.  */
  66     __const char *dli_sname;    /* Name of nearest symbol.  */
  67     void *dli_saddr;            /* Exact value of nearest symbol.  */
  68   } Dl_info;
  69 extern int dladdr __P ((void *__address, Dl_info *__info));
  70
  71 __END_DECLS
  72
  73 #endif  /* dlfcn.h */