libdm/misc/dmlib.h - main - githubmirror/lvm2

libdm/misc/dmlib.h
102 строки3 KB
Zdenek Kabelac
comments: fix and improve code comments
11 май 2026, 11:18
11 май 2026, 11:187d30411
/*
 * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
 * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
 *
 * This file is part of LVM2.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU Lesser General Public License v.2.1.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/*
 * This file must be included first by every library source file.
 */
#ifndef DM_LIB_H
#define DM_LIB_H

/*
 * Symbol export control macros
 *
 *   DM_EXPORT_NEW_SYMBOL(rettype, func, ver)
 *   DM_EXPORT_SYMBOL(func,ver)
 *   DM_EXPORT_SYMBOL_BASE(func)
 *
 * For functions that have multiple implementations these macros control
 * symbol export and versioning.
 *
 * Function definitions that exist in only one version never need to use
 * these macros.
 *
 * Backwards compatible implementations must include a version tag of
 * the form "_v1_02_104" as a suffix to the function name and use the
 * macro DM_EXPORT_SYMBOL to export the function and bind it to the
 * specified version string.
 *
 * Since versioning is only available with compilers supporting GNU symbol
 * versioning (GCC and Clang) the entire compatibility version should be
 * enclosed in '#if defined(GNU_SYMVER)',
 * for example:
 *
 *   DM_EXPORT_NEW_SYMBOL(int, dm_foo, 1_02_107)(int bar)
 *   {
 *     return bar;
 *   }
 *
 *   #if defined(GNU_SYMVER)
 *   // Backward compatible dm_foo() version 1.02.104
 *   DM_EXPORT_SYMBOL(dm_foo,1_02_104)
 *   int dm_foo_v1_02_104(void);
 *   int dm_foo_v1_02_104(void)
 *   {
 *     return 0;
 *   }
 *   #endif
 *
 * A prototype for the compatibility version is required as these
 * functions must not be declared static.
 *
 * The DM_EXPORT_SYMBOL_BASE macro is only used to export the base
 * versions of library symbols prior to the introduction of symbol
 * versioning: it must never be used for new symbols.
 */
#if defined(GNU_SYMVER)
# ifdef __has_attribute
#  if __has_attribute(symver)
#   define DM_EXPORT_NEW_SYMBOL(rettype, func, ver) \
	__attribute__((__symver__( #func "@@DM_" #ver ))) \
	__typeof__(func) func ##_v ##ver; \
	rettype func ##_v ##ver
#   define DM_EXPORT_SYMBOL(func, ver) \
	__attribute__((__symver__( #func "@DM_" #ver )))
#   define DM_EXPORT_SYMBOL_BASE(func) \
	__attribute__((__symver__( #func "@Base" )))
#  endif
# endif
# ifndef DM_EXPORT_NEW_SYMBOL
#  define DM_EXPORT_NEW_SYMBOL(rettype, func, ver) \
	__typeof__(func) func ##_v ##ver; \
	__asm__(".symver " #func "_v" #ver ", " #func "@@DM_" #ver ); \
	rettype func ##_v ##ver
#  define DM_EXPORT_SYMBOL(func, ver) \
	__asm__(".symver " #func "_v" #ver ", " #func "@DM_" #ver );
#  define DM_EXPORT_SYMBOL_BASE(func) \
	__asm__(".symver " #func "_base, " #func "@Base" );
# endif
#else
#define DM_EXPORT_NEW_SYMBOL(rettype, func, ver) rettype func
#define DM_EXPORT_SYMBOL(func, ver)
#define DM_EXPORT_SYMBOL_BASE(func)
#endif

#include "libdm/libdevmapper.h"
#include "libdm/dm-tools/util.h"
#include "libdm/misc/dm-logging.h"

#include <unistd.h>

#endif