openldap/include/ldap_cdefs.h
2003-11-26 07:16:36 +00:00

240 lines
8.9 KiB
C

/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 1998-2003 The OpenLDAP Foundation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*/
/* LDAP C Defines */
#ifndef _LDAP_CDEFS_H
#define _LDAP_CDEFS_H
#if defined(__cplusplus) || defined(c_plusplus)
# define LDAP_BEGIN_DECL extern "C" {
# define LDAP_END_DECL }
#else
# define LDAP_BEGIN_DECL /* begin declarations */
# define LDAP_END_DECL /* end declarations */
#endif
#if !defined(LDAP_NO_PROTOTYPES) && ( defined(LDAP_NEEDS_PROTOTYPES) || \
defined(__STDC__) || defined(__cplusplus) || defined(c_plusplus) )
/* ANSI C or C++ */
# define LDAP_P(protos) protos
# define LDAP_CONCAT1(x,y) x ## y
# define LDAP_CONCAT(x,y) LDAP_CONCAT1(x,y)
# define LDAP_STRING(x) #x /* stringify without expanding x */
# define LDAP_XSTRING(x) LDAP_STRING(x) /* expand x, then stringify */
#ifndef LDAP_CONST
# define LDAP_CONST const
#endif
#else /* no prototypes */
/* traditional C */
# define LDAP_P(protos) ()
# define LDAP_CONCAT(x,y) x/**/y
# define LDAP_STRING(x) "x"
#ifndef LDAP_CONST
# define LDAP_CONST /* no const */
#endif
#endif /* no prototypes */
#if (__GNUC__) * 1000 + (__GNUC_MINOR__) >= 2006
# define LDAP_GCCATTR(attrs) __attribute__(attrs)
#else
# define LDAP_GCCATTR(attrs)
#endif
/*
* Support for Windows DLLs.
*
* When external source code includes header files for dynamic libraries,
* the external source code is "importing" DLL symbols into its resulting
* object code. On Windows, symbols imported from DLLs must be explicitly
* indicated in header files with the __declspec(dllimport) directive.
* This is not totally necessary for functions because the compiler
* (gcc or MSVC) will generate stubs when this directive is absent.
* However, this is required for imported variables.
*
* The LDAP libraries, i.e. liblber and libldap, can be built as
* static or shared, based on configuration. Just about all other source
* code in OpenLDAP use these libraries. If the LDAP libraries
* are configured as shared, 'configure' defines the LDAP_LIBS_DYNAMIC
* macro. When other source files include LDAP library headers, the
* LDAP library symbols will automatically be marked as imported. When
* the actual LDAP libraries are being built, the symbols will not
* be marked as imported because the LBER_LIBRARY or LDAP_LIBRARY macros
* will be respectively defined.
*
* Any project outside of OpenLDAP with source code wanting to use
* LDAP dynamic libraries should explicitly define LDAP_LIBS_DYNAMIC.
* This will ensure that external source code appropriately marks symbols
* that will be imported.
*
* The slapd executable, itself, can be used as a dynamic library.
* For example, if a backend module is compiled as shared, it will
* import symbols from slapd. When this happens, the slapd symbols
* must be marked as imported in header files that the backend module
* includes. Remember that slapd links with various static libraries.
* If the LDAP libraries were configured as static, their object
* code is also part of the monolithic slapd executable. Thus, when
* a backend module imports symbols from slapd, it imports symbols from
* all of the static libraries in slapd as well. Thus, the SLAP_IMPORT
* macro, when defined, will appropriately mark symbols as imported.
* This macro should be used by shared backend modules as well as any
* other external source code that imports symbols from the slapd
* executable as if it were a DLL.
*
* Note that we don't actually have to worry about using the
* __declspec(dllexport) directive anywhere. This is because both
* MSVC and Mingw provide alternate (more effective) methods for exporting
* symbols out of binaries, i.e. the use of a DEF file.
*
* NOTE ABOUT BACKENDS: Backends can be configured as static or dynamic.
* When a backend is configured as dynamic, slapd will load the backend
* explicitly and populate function pointer structures by calling
* the backend's well-known initialization function. Because of this
* procedure, slapd never implicitly imports symbols from dynamic backends.
* This makes it unnecessary to tag various backend functions with the
* __declspec(dllimport) directive. This is because neither slapd nor
* any other external binary should ever be implicitly loading a backend
* dynamic module.
*
* Backends are supposed to be self-contained. However, it appears that
* back-meta DOES implicitly import symbols from back-ldap. This means
* that the __declspec(dllimport) directive should be marked on back-ldap
* functions (in its header files) if and only if we're compiling for
* windows AND back-ldap has been configured as dynamic AND back-meta
* is the client of back-ldap. When client is slapd, there is no effect
* since slapd does not implicitly import symbols.
*
* TODO(?): Currently, back-meta nor back-ldap is supported for Mingw32.
* Thus, there's no need to worry about this right now. This is something that
* may or may not have to be addressed in the future.
*/
/* LBER library */
#if defined(_WIN32) && \
((defined(LDAP_LIBS_DYNAMIC) && !defined(LBER_LIBRARY)) || \
(!defined(LDAP_LIBS_DYNAMIC) && defined(SLAPD_IMPORT)))
# define LBER_F(type) extern __declspec(dllimport) type
# define LBER_V(type) extern __declspec(dllimport) type
#else
# define LBER_F(type) extern type
# define LBER_V(type) extern type
#endif
/* LDAP library */
#if defined(_WIN32) && \
((defined(LDAP_LIBS_DYNAMIC) && !defined(LDAP_LIBRARY)) || \
(!defined(LDAP_LIBS_DYNAMIC) && defined(SLAPD_IMPORT)))
# define LDAP_F(type) extern __declspec(dllimport) type
# define LDAP_V(type) extern __declspec(dllimport) type
#else
# define LDAP_F(type) extern type
# define LDAP_V(type) extern type
#endif
/* AVL library */
#if defined(_WIN32) && defined(SLAPD_IMPORT)
# define LDAP_AVL_F(type) extern __declspec(dllimport) type
# define LDAP_AVL_V(type) extern __declspec(dllimport) type
#else
# define LDAP_AVL_F(type) extern type
# define LDAP_AVL_V(type) extern type
#endif
/* LDBM library */
#if defined(_WIN32) && defined(SLAPD_IMPORT)
# define LDAP_LDBM_F(type) extern __declspec(dllimport) type
# define LDAP_LDBM_V(type) extern __declspec(dllimport) type
#else
# define LDAP_LDBM_F(type) extern type
# define LDAP_LDBM_V(type) extern type
#endif
/* LDIF library */
#if defined(_WIN32) && defined(SLAPD_IMPORT)
# define LDAP_LDIF_F(type) extern __declspec(dllimport) type
# define LDAP_LDIF_V(type) extern __declspec(dllimport) type
#else
# define LDAP_LDIF_F(type) extern type
# define LDAP_LDIF_V(type) extern type
#endif
/* LUNICODE library */
#if defined(_WIN32) && defined(SLAPD_IMPORT)
# define LDAP_LUNICODE_F(type) extern __declspec(dllimport) type
# define LDAP_LUNICODE_V(type) extern __declspec(dllimport) type
#else
# define LDAP_LUNICODE_F(type) extern type
# define LDAP_LUNICODE_V(type) extern type
#endif
/* LUTIL library */
#if defined(_WIN32) && defined(SLAPD_IMPORT)
# define LDAP_LUTIL_F(type) extern __declspec(dllimport) type
# define LDAP_LUTIL_V(type) extern __declspec(dllimport) type
#else
# define LDAP_LUTIL_F(type) extern type
# define LDAP_LUTIL_V(type) extern type
#endif
/* REWRITE library */
#if defined(_WIN32) && defined(SLAPD_IMPORT)
# define LDAP_REWRITE_F(type) extern __declspec(dllimport) type
# define LDAP_REWRITE_V(type) extern __declspec(dllimport) type
#else
# define LDAP_REWRITE_F(type) extern type
# define LDAP_REWRITE_V(type) extern type
#endif
/* SLAPD (as a dynamic library exporting symbols) */
#if defined(_WIN32) && defined(SLAPD_IMPORT)
# define LDAP_SLAPD_F(type) extern __declspec(dllimport) type
# define LDAP_SLAPD_V(type) extern __declspec(dllimport) type
#else
# define LDAP_SLAPD_F(type) extern type
# define LDAP_SLAPD_V(type) extern type
#endif
/*
* C library. Mingw32 links with the dynamic C run-time library by default,
* so the explicit definition of CSTATIC will keep dllimport from
* being defined, if desired.
*
* MSVC defines the _DLL macro when the compiler is invoked with /MD or /MDd,
* which means the resulting object code will be linked with the dynamic
* C run-time library.
*
* Technically, it shouldn't be necessary to redefine any functions that
* the headers for the C library should already contain. Nevertheless, this
* is here as a safe-guard.
*
* TODO: Determine if these macros ever get expanded for Windows. If not,
* the declspec expansion can probably be removed.
*/
#if (defined(__MINGW32__) && !defined(CSTATIC)) || \
(defined(_MSC_VER) && defined(_DLL))
# define LDAP_LIBC_F(type) extern __declspec(dllimport) type
# define LDAP_LIBC_V(type) extern __declspec(dllimport) type
#else
# define LDAP_LIBC_F(type) extern type
# define LDAP_LIBC_V(type) extern type
#endif
#endif /* _LDAP_CDEFS_H */