glibc/bits/dlfcn.h

/* System dependent definitions for run-time dynamic loading.
   Copyright (C) 1996-2020 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef _DLFCN_H
# error "Never use <bits/dlfcn.h> directly; include <dlfcn.h> instead."
#endif

/* The MODE argument to `dlopen' contains one of the following: */
#define RTLD_LAZY	0x00001	/* Lazy function call binding.  */
#define RTLD_NOW	0x00002	/* Immediate function call binding.  */
#define	RTLD_BINDING_MASK   0x3	/* Mask of binding time value.  */
#define RTLD_NOLOAD	0x00004	/* Do not load the object.  */
#define RTLD_DEEPBIND	0x00008	/* Use deep binding.  */

/* If the following bit is set in the MODE argument to `dlopen',
   the symbols of the loaded object and its dependencies are made
   visible as if the object were linked directly into the program.  */
#define RTLD_GLOBAL	0x00100

/* Unix98 demands the following flag which is the inverse to RTLD_GLOBAL.
   The implementation does this by default and so we can define the
   value to zero.  */
#define RTLD_LOCAL	0

/* Do not delete object when closed.  */
#define RTLD_NODELETE	0x01000

#ifdef __USE_GNU
/* To support profiling of shared objects it is a good idea to call
   the function found using `dlsym' using the following macro since
   these calls do not use the PLT.  But this would mean the dynamic
   loader has no chance to find out when the function is called.  The
   macro applies the necessary magic so that profiling is possible.
   Rewrite
	foo = (*fctp) (arg1, arg2);
   into
        foo = DL_CALL_FCT (fctp, (arg1, arg2));
*/
# define DL_CALL_FCT(fctp, args) \
  (_dl_mcount_wrapper_check ((void *) (fctp)), (*(fctp)) args)

__BEGIN_DECLS

/* This function calls the profiling functions.  */
extern void _dl_mcount_wrapper_check (void *__selfpc) __THROW;

__END_DECLS

#endif