ares.h: stricter CARES_EXTERN linkage decorations logic

No API change involved.

Makefile.am

@@ -114,29 +114,23 @@ libcares_la_LDFLAGS = $(AM_LDFLAGS) $(libcares_la_LDFLAGS_EXTRA)
 # Add -Werror if defined
 CFLAGS += @CARES_CFLAG_EXTRAS@
 
-CFLAG_CARES_SYMBOL_HIDING = @CFLAG_CARES_SYMBOL_HIDING@
-
-# For Windows build targets, when building or using static c-ares
 if USE_CPPFLAG_CARES_STATICLIB
-AM_CPPFLAGS += -DCARES_STATICLIB
+AM_CPPFLAGS += $(CPPFLAG_CARES_STATICLIB)
 endif
 
+libcares_la_CFLAGS_EXTRA =
+
+libcares_la_CPPFLAGS_EXTRA = -DCARES_BUILDING_LIBRARY
+
 if DOING_CARES_SYMBOL_HIDING
-if USE_CPPFLAG_CARES_BUILDING_LIBRARY
-libcares_la_CPPFLAGS = $(AM_CPPFLAGS) -DCARES_SYMBOL_HIDING -DCARES_BUILDING_LIBRARY
-else
-libcares_la_CPPFLAGS = $(AM_CPPFLAGS) -DCARES_SYMBOL_HIDING
-endif
-libcares_la_CFLAGS = $(AM_CFLAGS) $(CFLAG_CARES_SYMBOL_HIDING)
-else
-if USE_CPPFLAG_CARES_BUILDING_LIBRARY
-libcares_la_CPPFLAGS = $(AM_CPPFLAGS) -DCARES_BUILDING_LIBRARY
-else
-libcares_la_CPPFLAGS = $(AM_CPPFLAGS)
-endif
-libcares_la_CFLAGS = $(AM_CFLAGS)
+libcares_la_CFLAGS_EXTRA += $(CFLAG_CARES_SYMBOL_HIDING)
+libcares_la_CPPFLAGS_EXTRA += -DCARES_SYMBOL_HIDING
 endif
 
+libcares_la_CFLAGS = $(AM_CFLAGS) $(libcares_la_CFLAGS_EXTRA)
+
+libcares_la_CPPFLAGS = $(AM_CPPFLAGS) $(libcares_la_CPPFLAGS_EXTRA)
+
 # Makefile.inc provides the CSOURCES and HHEADERS defines
 include Makefile.inc
 

ares.h

@@ -75,22 +75,18 @@ extern "C" {
 ** c-ares external API function linkage decorations.
 */
 
-#if !defined(CARES_STATICLIB) && \
-   (defined(WIN32) || defined(_WIN32) || defined(__SYMBIAN32__))
-   /* __declspec function decoration for Win32 and Symbian DLL's */
+#ifdef CARES_STATICLIB
+#  define CARES_EXTERN
+#elif defined(WIN32) || defined(_WIN32) || defined(__SYMBIAN32__)
 #  if defined(CARES_BUILDING_LIBRARY)
 #    define CARES_EXTERN  __declspec(dllexport)
 #  else
 #    define CARES_EXTERN  __declspec(dllimport)
 #  endif
+#elif defined(CARES_BUILDING_LIBRARY) && defined(CARES_SYMBOL_HIDING)
+#  define CARES_EXTERN CARES_SYMBOL_SCOPE_EXTERN
 #else
-   /* visibility function decoration for other cases */
-#  if !defined(CARES_SYMBOL_HIDING) || \
-     defined(WIN32) || defined(_WIN32) || defined(__SYMBIAN32__)
-#    define CARES_EXTERN
-#  else
-#    define CARES_EXTERN CARES_SYMBOL_SCOPE_EXTERN
-#  endif
+#  define CARES_EXTERN
 #endif
 
 

configure.ac

@@ -110,32 +110,36 @@ AM_CONDITIONAL([CARES_LT_SHLIB_USE_NO_UNDEFINED],
 AM_CONDITIONAL([CARES_LT_SHLIB_USE_MIMPURE_TEXT],
   [test "x$xc_lt_shlib_use_mimpure_text" = 'xyes'])
 
+#
+# Due to libtool and automake machinery limitations of not allowing
+# specifying separate CPPFLAGS or CFLAGS when compiling objects for
+# inclusion of these in shared or static libraries, we are forced to
+# build using separate configure runs for shared and static libraries
+# on systems where different CPPFLAGS or CFLAGS are mandatory in order
+# to compile objects for each kind of library. Notice that relying on
+# the '-DPIC' CFLAG that libtool provides is not valid given that the
+# user might for example choose to build static libraries with PIC.
+#
 
-AC_MSG_CHECKING([if we need CARES_BUILDING_LIBRARY])
-use_cppflag_cares_building_library="no"
-use_cppflag_cares_staticlib="no"
-CPPFLAG_CARES_STATICLIB=""
-case $host in
-  *-*-mingw*)
-    AC_MSG_RESULT(yes)
-    use_cppflag_cares_building_library="yes"
-    AC_MSG_CHECKING([if we need CARES_STATICLIB])
-    if test "X$enable_shared" = "Xno"
-    then
-      AC_MSG_RESULT(yes)
-      use_cppflag_cares_staticlib="yes"
-      CPPFLAG_CARES_STATICLIB="-DCARES_STATICLIB"
-    else
-      AC_MSG_RESULT(no)
-    fi
-    ;;
-  *)
-    AC_MSG_RESULT(no)
-    ;;
-esac
-AM_CONDITIONAL(USE_CPPFLAG_CARES_BUILDING_LIBRARY, test x$use_cppflag_cares_building_library = xyes)
-AM_CONDITIONAL(USE_CPPFLAG_CARES_STATICLIB, test x$use_cppflag_cares_staticlib = xyes)
-AC_SUBST(CPPFLAG_CARES_STATICLIB)
+#
+# Make our Makefile.am files use the staticlib CPPFLAG only when strictly
+# targeting a static library and not building its shared counterpart.
+#
+
+AM_CONDITIONAL([USE_CPPFLAG_CARES_STATICLIB],
+  [test "x$xc_lt_build_static_only" = 'xyes'])
+
+#
+# Make staticlib CPPFLAG variable and its definition visible in output
+# files unconditionally, providing an empty definition unless strictly
+# targeting a static library and not building its shared counterpart.
+#
+
+CPPFLAG_CARES_STATICLIB=
+if test "x$xc_lt_build_static_only" = 'xyes'; then
+  CPPFLAG_CARES_STATICLIB='-DCARES_STATICLIB'
+fi
+AC_SUBST([CPPFLAG_CARES_STATICLIB])
 
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