elf/dlfcn.h

   1 /* User functions for run-time dynamic loading.
   2    Copyright (C) 1995, 1996, 1997, 1998 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 #define _DLFCN_H 1
  22
  23 #include <features.h>
  24 #define __need_NULL
  25 #include <stddef.h>
  26
  27 /* Collect various system dependand definitions and declarations.  */
  28 #include <bits/dlfcn.h>
  29
  30 /* If the first argument of `dlsym' or `dlvsym' is set to RTLD_NEXT
  31    the run-time address of the symbol called NAME in the next shared
  32    object is returned.  The "next" relation is defined by the order
  33    the shared objects were loaded.  */
  34 #define RTLD_NEXT       ((void *) -1l)
  35
  36 /* If the first argument to `dlsym' or `dlvsym' is set to RTLD_DEFAULT
  37    the run-time address of the symbol called NAME in the global scope
  38    is returned.  */
  39 #define RTLD_DEFAULT    NULL
  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 *__restrict __handle,
  54                          __const char *__restrict __name));
  55
  56 #ifdef __USE_GNU
  57 /* Find the run-time address in the shared object HANDLE refers to
  58    of the symbol called NAME with VERSION.  */
  59 extern void *dlvsym __P ((void *__restrict __handle,
  60                           __const char *__restrict __name,
  61                           __const char *__restrict __version));
  62 #endif
  63
  64 /* When any of the above functions fails, call this function
  65    to return a string describing the error.  Each call resets
  66    the error string so that a following call returns null.  */
  67 extern char *dlerror __P ((void));
  68
  69 #ifdef __USE_GNU
  70 /* Fill in *INFO with the following information about ADDRESS.
  71    Returns 0 iff no shared object's segments contain that address.  */
  72 typedef struct
  73   {
  74     __const char *dli_fname;    /* File name of defining object.  */
  75     void *dli_fbase;            /* Load address of that object.  */
  76     __const char *dli_sname;    /* Name of nearest symbol.  */
  77     void *dli_saddr;            /* Exact value of nearest symbol.  */
  78   } Dl_info;
  79 extern int dladdr __P ((const void *__address, Dl_info *__info));
  80
  81 /* To support profiling of shared objects it is a good idea to call
  82    the function found using `dlsym' using the following macro since
  83    these calls do not use the PLT.  But this would mean the dynamic
  84    loader has no chance to find out when the function is called.  The
  85    macro applies the necessary magic so that profiling is possible.
  86    Rewrite
  87         foo = (*fctp) (arg1, arg2);
  88    into
  89         foo = DL_CALL_FCT (fctp, (arg1, arg2));
  90 */
  91 # define DL_CALL_FCT(fctp, args) \
  92   (_dl_mcount_wrapper_check (fctp), (*(fctp)) args)
  93
  94 /* This function calls the profiling functions.  */
  95 extern void _dl_mcount_wrapper_check __P ((void *__selfpc));
  96 #endif
  97
  98 __END_DECLS
  99
 100 #endif  /* dlfcn.h */