diff --git a/Makefile.am b/Makefile.am
index 1972104..fe3a70a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -120,6 +120,8 @@ src_backend_pyloader_libpyloader_la_CPPFLAGS = \
 		-DLOCALEDIR="\"$(localedir)\"" \
 		$(PYTHON_CPPFLAGS) \
 		$(GLIBMM_CFLAGS)
+src_backend_pyloader_libpyloader_la_CXXFLAGS = \
+		$(VISIB_HIDDEN)
 src_backend_pyloader_libpyloader_la_LIBADD = \
 		$(PYTHON_LDFLAGS) \
 		$(PYTHON_EXTRA_LIBS) \
@@ -157,6 +159,8 @@ src_backend_libbackend_la_CPPFLAGS = \
 		-DLOCALEDIR="\"$(localedir)\"" \
 		$(PYTHON_CPPFLAGS) \
 		$(GLIBMM_CFLAGS)
+src_backend_libbackend_la_CXXFLAGS = \
+		$(VISIB_HIDDEN)
 src_backend_libbackend_la_LIBADD = \
 		src/backend/pyloader/libpyloader.la
 src_backend_libbackend_la_LDFLAGS = \
@@ -210,6 +214,7 @@ sgpemv2_CPPFLAGS = \
 		$(GTKMM_CFLAGS) \
 		$(PYTHON_CPPFLAGS) \
 		$(GTHREAD_CFLAGS)
+sgpemv2_CXXFLAGS = $(VISIB_HIDDEN)
 sgpemv2_LDFLAGS = $(LT_LDFLAGS)
 sgpemv2_LDADD = \
 		src/backend/libbackend.la \
diff --git a/configure.ac b/configure.ac
index 1d46dc1..a6dea25 100644
--- a/configure.ac
+++ b/configure.ac
@@ -60,11 +60,11 @@ CAIRO_VERSION=1.0.0
 
 dnl c++ compiler and flags
 AC_PROG_CXX
-AC_CHECK_CXXFLAG([Wall])
-AC_CHECK_CXXFLAG([pedantic])
-AC_CHECK_CXXFLAG([Wextra])
-AC_CHECK_CXXFLAG([Wno-long-long])
-AC_CHECK_LDFLAG([--as-needed])
+AC_CHECK_CXXFLAG([CXXFLAGS], [Wall])
+AC_CHECK_CXXFLAG([CXXFLAGS], [pedantic])
+AC_CHECK_CXXFLAG([CXXFLAGS], [Wextra])
+AC_CHECK_CXXFLAG([CXXFLAGS], [Wno-long-long])
+AC_CHECK_LDFLAG([LDFLAGS],[--as-needed])
 
 AC_PROG_INSTALL
 
@@ -119,8 +119,9 @@ AC_COMPILE_IFELSE(
 		AC_DEFINE([SG_DLLLOCAL],[__attribute__ ((visibility("hidden")))])
 		AC_DEFINE([SG_DLLPUBLIC],[__attribute__ ((visibility("default")))])
 
-		AC_CHECK_CXXFLAG([fvisibility=hidden])
-		AC_CHECK_CXXFLAG([fvisibility-inlines-hidden])
+		AC_CHECK_CXXFLAG([VISIB_HIDDEN], [fvisibility=hidden])
+		AC_SUBST([VISIB_HIDDEN])
+		AC_CHECK_CXXFLAG([CXXFLAGS],[fvisibility-inlines-hidden])
 	],[
 		AC_MSG_RESULT([no])
 		AC_DEFINE([SG_DLLIMPORT],[/* unsupported */])
diff --git a/m4/compilerflags.m4 b/m4/compilerflags.m4
index bb651b3..a843dc6 100644
--- a/m4/compilerflags.m4
+++ b/m4/compilerflags.m4
@@ -2,22 +2,27 @@ dnl  **************************************************
 dnl    Copyright (C) 2004   Matteo Settenvini
 dnl  **************************************************
 
-dnl ---------- AX_CHECK_CXXFLAG ---------------------
+dnl ---------- AC_CHECK_CXXFLAG ---------------------
 dnl This macro checks if a particular flag for the 
-dnl C++ compiler works. If it is so, it adds the flag 
-dnl to the CXXFLAGS variable. 
-dnl Example of usage : AC_CHECK_CXXFLAG([Wall])
+dnl C++ compiler works. If it is so, it puts the flag 
+dnl into the first macro parameter. 
+dnl Example of usage : AC_CHECK_CXXFLAG([CXXFLAGS],[Wall])
 dnl -------------------------------------------------
 AC_DEFUN([AC_CHECK_CXXFLAG],
-[ AC_REQUIRE([AC_PROG_CXX])dnl
-  AC_MSG_CHECKING([whether $CXX supports the -$1 flag])
+[ if test -z "$1" -o -z "$2"; then
+	AC_MSG_FAILURE([Wrong parameters passed to the m4 macro. 
+Please contact the package mantainer.])
+  fi
+  AC_REQUIRE([AC_PROG_CXX])dnl
+  AC_MSG_CHECKING([whether $CXX supports the -$2 flag])
   ac_check_cxxflags=$CXXFLAGS
-  CXXFLAGS="-$1"
+  CXXFLAGS="-$2"
   AC_LANG_PUSH([C++])
   AC_COMPILE_IFELSE(
     AC_LANG_PROGRAM([], [return 0;]),
     [AC_MSG_RESULT([yes])
-      CXXFLAGS="-$1 $ac_check_cxxflags" ],
+      CXXFLAGS="$ac_check_cxxflags"
+      $1="-$2 $[$1]" ],
     [AC_MSG_RESULT([no])
       CXXFLAGS=$ac_check_cxxflags ]
   )
@@ -29,19 +34,24 @@ AC_DEFUN([AC_CHECK_CXXFLAG],
 dnl ---------- AC_CHECK_CFLAG ---------------------
 dnl This macro checks if a particular flag for the 
 dnl C compiler works. If it is so, it adds the flag 
-dnl to the CFLAGS variable. 
-dnl Example of usage : AC_CHECK_CFLAG([Wall])
+dnl into the first macro parameter.
+dnl Example of usage : AC_CHECK_CFLAG([CFLAGS],[Wall])
 dnl -------------------------------------------------
 AC_DEFUN([AC_CHECK_CFLAG],
-[ AC_REQUIRE([AC_PROG_CC])dnl
-  AC_MSG_CHECKING([whether $CC supports the -$1 flag])
+[ if test -z "$1" -o -z "$2"; then
+	AC_MSG_FAILURE([Wrong parameters passed to the m4 macro. 
+Please contact the package mantainer.])
+  fi
+  AC_REQUIRE([AC_PROG_CC])dnl
+  AC_MSG_CHECKING([whether $CC supports the -$2 flag])
   ac_check_cflags=$CFLAGS
-  CFLAGS="-$1"
+  CFLAGS="-$2"
   AC_LANG_PUSH([C])
   AC_COMPILE_IFELSE(
     AC_LANG_PROGRAM([], [return 0;]),
     [AC_MSG_RESULT([yes])
-      CFLAGS="-$1 $ac_check_cflags" ],
+      CFLAGS="$ac_check_cflags"
+      $1="-$2 $[$1]" ],
     [AC_MSG_RESULT([no])
       CFLAGS=$ac_check_cflags ]
   )
diff --git a/m4/linkingflags.m4 b/m4/linkingflags.m4
index e1ace94..802cbe8 100644
--- a/m4/linkingflags.m4
+++ b/m4/linkingflags.m4
@@ -5,19 +5,24 @@ dnl  **************************************************
 dnl ---------- AX_CHECK_LDFLAG ---------------------
 dnl This macro checks if a particular flag for the 
 dnl C++ compiler works. If it is so, it adds the flag 
-dnl to the CXXFLAGS variable. 
-dnl Example of usage : AC_CHECK_LDFLAG([--as-needed])
+dnl to the end of the first parameter. 
+dnl Example of usage : AC_CHECK_LDFLAG([LDFLAGS],[--as-needed])
 dnl -------------------------------------------------
 AC_DEFUN([AC_CHECK_LDFLAG],
-[ AC_REQUIRE([AC_PROG_CC])dnl
-  AC_MSG_CHECKING([whether the linker supports the $1 flag])
+[   if test -z "$1" -o -z "$2"; then
+	AC_MSG_FAILURE([Wrong parameters passed to the m4 macro. 
+Please contact the package mantainer.])
+  fi
+  AC_REQUIRE([AC_PROG_CC])dnl
+  AC_MSG_CHECKING([whether the linker supports the $2 flag])
   ac_check_ldflags=$LDFLAGS
-  LDFLAGS="-Wl,$1"
+  LDFLAGS="-Wl,$2"
   AC_LANG_PUSH([C])
   AC_LINK_IFELSE(
     AC_LANG_PROGRAM([], [return 0;]),
     [AC_MSG_RESULT([yes])
-      LDFLAGS="-Wl,$1 $ac_check_ldflags" ],
+      LDFLAGS=$ac_check_ldflags
+      $1="-Wl,$2 $[$1]" ],
     [AC_MSG_RESULT([no])
       LDFLAGS=$ac_check_ldflags ]
   )
diff --git a/src/templates/parameter.tcc b/src/templates/parameter.tcc
index 579dd43..ce60062 100644
--- a/src/templates/parameter.tcc
+++ b/src/templates/parameter.tcc
@@ -1,4 +1,4 @@
-// src/templates/parameter.tcc - Copyright 2005, 2006, University
+// Src/templates/parameter.tcc - Copyright 2005, 2006, University
 //               of Padova, dept. of Pure and Applied
 //               Mathematics
 //