+@node Exported Symbols of Shared Libraries
+@section Controlling the Exported Symbols of Shared Libraries
+
@c Documentation of gnulib module 'visibility'.
@c Copyright (C) 2005-2006, 2009 Free Software Foundation, Inc.
The gnulib autoconf macro @code{gl_VISIBILITY} tests for GCC 4.0 or newer.
It defines a Makefile variable @code{@@CFLAG_VISIBILITY@@} containing
@samp{-fvisibility=hidden} or nothing. It also defines as a C macro and
-as a Makefile variable: @@HAVE_VISIBILITY@@. Its value is 1 when symbol
+as a substituted variable: @@HAVE_VISIBILITY@@. Its value is 1 when symbol
visibility control is supported, and 0 otherwise.
To use this module in a library, say libfoo, you will do these steps:
@item
Define a macro specific to your library like this.
@smallexample
-#if @@HAVE_VISIBILITY@@ && BUILDING_LIBFOO
+#if BUILDING_LIBFOO && HAVE_VISIBILITY
#define LIBFOO_DLL_EXPORTED __attribute__((__visibility__("default")))
#else
#define LIBFOO_DLL_EXPORTED
Note about other compilers: MSVC support can be added easily, by extending
the definition of the macro mentioned above, to something like this:
@smallexample
-#if @@HAVE_VISIBILITY@@ && BUILDING_LIBFOO
+#if BUILDING_LIBFOO && HAVE_VISIBILITY
#define LIBFOO_DLL_EXPORTED __attribute__((__visibility__("default")))
-#elif defined _MSC_VER && BUILDING_LIBFOO
+#elif BUILDING_LIBFOO && defined _MSC_VER
#define LIBFOO_DLL_EXPORTED __declspec(dllexport)
#elif defined _MSC_VER
#define LIBFOO_DLL_EXPORTED __declspec(dllimport)