* libltdl/lt__alloc.h: Declare exported functions with LT_SCOPE

for mingw32.
* libltdl/lt__dirent.h: Ditto.
* libltdl/argz._h: Ditto.  Be careful about not requiring
additional libltdl files when used outside of libltdl.
* libltdl/slist.h: Ditto.
* HACKING: Add a section on libltdl implementation layering.

ChangeLog

@@ -1,3 +1,14 @@
+2004-10-03  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>,
+	    Gary V. Vaughan  <gary@gnu.org>
+
+	* libltdl/lt__alloc.h: Declare exported functions with LT_SCOPE
+	for mingw32.
+	* libltdl/lt__dirent.h: Ditto.
+	* libltdl/argz._h: Ditto.  Be careful about not requiring
+	additional libltdl files when used outside of libltdl.
+	* libltdl/slist.h: Ditto.
+	* HACKING: Add a section on libltdl implementation layering.
+
 2004-10-03  Gary V. Vaughan  <gary@gnu.org>
 
 	* tests/quote.test: echo is called ECHO now.  Make sure we extract

HACKING

@@ -100,7 +100,91 @@ and is not part of a release distribution.
   variable names.  Don't use `return', instead echo the result of a
   function and call it from within backquotes.
 
-6. Release Procedure
+6. Abstraction layers in libltdl
+================================
+
+* The libltdl API uses a layered approach to differentiate internal and
+  external interfaces, among other things.  To keep the abstraction
+  consistent, files in a given layer may only use APIs from files in the
+  lower layers.  The exception to this is lt__glibc.h which serves a
+  dual purpose, as explained later.
+
+* At the bottom of the stack we have the system abstraction layer,
+  which tries to smooth over the cracks where there are differences
+  between host systems and compilers.  config.h is generated at
+  configure time and is not installed; lt_system.h is an installed
+  file and cannot use macros from config.h:
+
+	lt_system.h	../config.h
+
+* Next up is the libc abstraction layer, which provides a uniform api
+  to various system libc interfaces that differ between hosts supported
+  by libtool.  Typically, the files that implement this layer begin:
+
+  #if defined(HAVE_CONFIG_H)
+  #  include HAVE_CONFIG_H
+  #endif
+  #include "lt_system.h"
+
+  Or if they are installed headers that must work outside the libtool
+  source tree, simply:
+
+  #include <libltdl/lt_system.h>
+
+  This layer's interface is defined by files that are usually named with
+  a leading `lt__':
+
+	,------------.	,-----------.	,------.	,-------.
+	|lt__dirent.h|	|lt__alloc.h|	|argz.h|	|slist.h|
+	+------------+	+-----------+	+------+	+-------+
+	|lt__dirent.c|	|lt__alloc.c|	|argz.c|	|slist.c|
+	`------------'	`-----------'	`------'	`-------'
+
+  The exceptions here are argz.h and slist.h which are used
+  independently of libltdl in other projects.
+
+* There is also a sub-layer that can be used either by the headers that
+  implement it, in which case its function is to avoid namespace clashes
+  when linked with the GNU C library; Or it can be included by code that
+  wants to program against a glibc like interface, where it also serves
+  the function of pulling in all the glibc-like functionality used by
+  libltdl from a single:
+
+  #include <libltdl/lt__glibc.h>
+
+  It consists of the single file:
+
+	lt__glibc.h
+
+* The next layer are the subsystems of the exported libltdl API, which
+  are defined by files that are named with a leading `lt_' (no double
+  underscore!):
+
+	,----------.	,-------------.
+	|lt_error.h|	|lt_dlloader.h|
+	+----------+	+-------------+
+	|lt_error.c|	|lt_dlloader.c|
+	`----------'	`-------------'
+
+
+* The top layer of the stack is the libltdl API proper, which includes
+  the subsystems automatically:
+
+	,------.
+	|ltdl.h|
+	+------+
+	|ltdl.c|
+	`------'
+
+* And finally, there is an additional internal only layer (as evidenced
+  by the `lt__' prefix to the filename!) that defines additional
+  internal interfaces that are not exported to libltdl clients, but are
+  shared between internal files:
+
+	lt__private.h
+
+
+7. Release Procedure
 ====================
 
 * If you are a libtool maintainer, but have not yet registered your

libltdl/argz_.h

@@ -35,23 +35,30 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 
 #if defined(LTDL)
 #  include "lt__glibc.h"
+#else
+#  define LT_SCOPE
 #endif
 
 #if defined(_cplusplus)
 extern "C" {
 #endif
 
-error_t	argz_append	(char **pargz, size_t *pargz_len,
-			 const char *buf, size_t buf_len);
-error_t	argz_create_sep	(const char *str, int delim,
-			 char **pargz, size_t *pargz_len);
-error_t	argz_insert	(char **pargz, size_t *pargz_len,
-			 char *before, const char *entry);
-char *	argz_next	(char *argz, size_t argz_len, const char *entry);
-void	argz_stringify	(char *argz, size_t argz_len, int sep);
+LT_SCOPE error_t argz_append	(char **pargz, size_t *pargz_len,
+				 const char *buf, size_t buf_len);
+LT_SCOPE error_t argz_create_sep(const char *str, int delim,
+				 char **pargz, size_t *pargz_len);
+LT_SCOPE error_t argz_insert	(char **pargz, size_t *pargz_len,
+				 char *before, const char *entry);
+LT_SCOPE char *	 argz_next	(char *argz, size_t argz_len,
+				 const char *entry);
+LT_SCOPE void	 argz_stringify	(char *argz, size_t argz_len, int sep);
 
 #if defined(_cplusplus)
 }
 #endif
 
+#if !defined(LTDL)
+#  undef LT_SCOPE
+#endif
+
 #endif /*!defined(LT__ARGZ_H)*/

libltdl/lt__alloc.h

@@ -45,12 +45,12 @@ LT_BEGIN_C_DECLS
 /* If set, this function is called when memory allocation has failed.  */
 extern void (*lt__alloc_die) (void);
 
-void *lt__malloc (size_t n);
-void *lt__zalloc (size_t n);
-void *lt__realloc (void *mem, size_t n);
-void *lt__memdup (void const *mem, size_t n);
+LT_SCOPE void *lt__malloc (size_t n);
+LT_SCOPE void *lt__zalloc (size_t n);
+LT_SCOPE void *lt__realloc (void *mem, size_t n);
+LT_SCOPE void *lt__memdup (void const *mem, size_t n);
 
-char *lt__strdup (const char *string);
+LT_SCOPE char *lt__strdup (const char *string);
 
 LT_END_C_DECLS
 

libltdl/lt__dirent.h

@@ -86,9 +86,9 @@ typedef struct
 } DIR;
 
 
-DIR *		opendir		(const char *path);
-struct dirent *	readdir		(DIR *entry);
-void		closedir	(DIR *entry);
+LT_SCOPE DIR *		opendir		(const char *path);
+LT_SCOPE struct dirent *readdir		(DIR *entry);
+LT_SCOPE void		closedir	(DIR *entry);
 
 LT_END_C_DECLS
 

libltdl/slist.h

@@ -40,10 +40,15 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 #if !defined(SLIST_H)
 #define SLIST_H 1
 
-#include <libltdl/lt_system.h>
+#if defined(LTDL)
+#  include <libltdl/lt_system.h>
+#else
+#  define LT_SCOPE
+#endif
 
-
-LT_BEGIN_C_DECLS
+#if defined(_cplusplus)
+extern "C" {
+#endif
 
 typedef struct slist {
   struct slist *next;		/* chain forward pointer*/
@@ -76,6 +81,12 @@ LT_SCOPE void *	slist_foreach   (SList *slist, SListCallback *foreach,
 LT_SCOPE SList *slist_box	(const void *userdata);
 LT_SCOPE void *	slist_unbox	(SList *item);
 
-LT_END_C_DECLS
+#if defined(_cplusplus)
+}
+#endif
+
+#if !defined(LTDL)
+#  undef LT_SCOPE
+#endif
 
 #endif /*!defined(SLIST_H)*/