/* $OpenLDAP$ */
-/*
- * Copyright 1998,1999 The OpenLDAP Foundation, Redwood City, California, USA
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 1998-2005 The OpenLDAP Foundation.
* All rights reserved.
*
- * Redistribution and use in source and binary forms are permitted only
- * as authorized by the OpenLDAP Public License. A copy of this
- * license is available at http://www.OpenLDAP.org/license.html or
- * in file LICENSE in the top-level directory of the distribution.
+ * 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 */
# define LDAP_END_DECL /* end declarations */
#endif
-#if !defined(__NO_PROTOTYPES) && ( defined(__NEED_PROTOTYPES) || \
+#if !defined(LDAP_NO_PROTOTYPES) && ( defined(LDAP_NEEDS_PROTOTYPES) || \
defined(__STDC__) || defined(__cplusplus) || defined(c_plusplus) )
/* ANSI C or C++ */
#endif /* no prototypes */
-#if _WIN32 && _DLL
-# define LDAP_F_IMPORT extern __declspec( dllimport )
-# define LDAP_F_EXPORT extern __declspec( dllexport )
-#else
-# define LDAP_F_IMPORT extern
-# define LDAP_F_EXPORT extern
-#endif
-
#if (__GNUC__) * 1000 + (__GNUC_MINOR__) >= 2006
# define LDAP_GCCATTR(attrs) __attribute__(attrs)
#else
# define LDAP_GCCATTR(attrs)
#endif
-/* Proper support for NT dynamic libraries. */
-
/*
- * C library. Mingw32 links with the C run-time library by default,
- * so the explicit definition of CSTATIC will keep dllimport from
- * being defined.
+ * 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.
*/
-#if (defined(__MINGW32__) && !defined(CSTATIC) || \
- defined(_WIN32) && defined(_DLL))
-# define LIBC_F(type) extern __declspec(dllimport) type
+
+/* 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 LIBC_F(type) extern type
+# define LDAP_F(type) extern type
+# define LDAP_V(type) extern type
#endif
/* AVL library */
-#if defined(LIBAVL_DECL) && defined(_WIN32)
-# define LIBAVL_F(type) extern __declspec(LIBAVL_DECL) type
+#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 LIBAVL_F(type) extern type
+# define LDAP_AVL_F(type) extern type
+# define LDAP_AVL_V(type) extern type
#endif
-/* LBER library */
-#if defined(LIBLBER_DECL) && defined(_WIN32)
-# define LIBLBER_F(type) extern __declspec(LIBLBER_DECL) type
+/* LDBM library */
+/* Not exported/imported any more */
+# define LDAP_LDBM_F(type) extern type
+# define LDAP_LDBM_V(type) extern type
+
+/* 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 LIBLBER_F(type) extern type
+# define LDAP_LDIF_F(type) extern type
+# define LDAP_LDIF_V(type) extern type
#endif
-/* LDAP library */
-#if defined(LIBLDAP_DECL) && defined(_WIN32)
-# define LIBLDAP_F(type) extern __declspec(LIBLDAP_DECL) type
+/* 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 LIBLDAP_F(type) extern type
+# define LDAP_LUNICODE_F(type) extern type
+# define LDAP_LUNICODE_V(type) extern type
#endif
-/* LDBM library */
-#if defined(LIBLDBM_DECL) && defined(_WIN32)
-# define LIBLDBM_F(type) extern __declspec(LIBLDBM_DECL) type
+/* 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 LIBLDBM_F(type) extern type
+# define LDAP_LUTIL_F(type) extern type
+# define LDAP_LUTIL_V(type) extern type
#endif
-/* LDIF library */
-#if defined(LIBLDIF_DECL) && defined(_WIN32)
-# define LIBLDIF_F(type) extern __declspec(LIBLDIF_DECL) type
+/* 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 LIBLDIF_F(type) extern type
+# define LDAP_REWRITE_F(type) extern type
+# define LDAP_REWRITE_V(type) extern type
#endif
-/* LUTIL library */
-#if defined(LIBLUTIL_DECL) && defined(_WIN32)
-# define LIBLUTIL_F(type) extern __declspec(LIBLUTIL_DECL) type
+/* 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 LIBLUTIL_F(type) extern type
+# define LDAP_SLAPD_F(type) extern type
+# define LDAP_SLAPD_V(type) extern type
#endif
-/* SLAPD (as a module exporting symbols */
-#if defined(LIBSLAPD_DECL) && defined(_WIN32)
-# define LIBSLAPD_F(type) extern __declspec(LIBSLAPD_DECL) type
+/*
+ * 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 LIBSLAPD_F(type) extern type
+# define LDAP_LIBC_F(type) extern type
+# define LDAP_LIBC_V(type) extern type
#endif
#endif /* _LDAP_CDEFS_H */
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