diff --git a/config/CONFIG.Host.Linux b/config/CONFIG.Host.Linux
index 51644d86a..72a125603 100644
--- a/config/CONFIG.Host.Linux
+++ b/config/CONFIG.Host.Linux
@@ -13,8 +13,15 @@ RANLIB = ranlib -t
 
 # Configure OS vendor C compiler
 ACC = acc
-ACC_ANSI = $(ACC)
-ACC_STRICT = $(ACC) -Xc
+#ACC_ANSI = $(ACC)
+ACC_ANSI = $(ACC) -ansi -D_SVID_SOURCE
+#ACC_STRICT = $(ACC) -Xc
+ACC_STRICT = $(ACC)  -ansi -pedantic -D_SVID_SOURCE
+
+
+OP_SYS_FLAGS = -D_BSD_SOURCE -D_POSIX_SOURCE
+
+
 ACC_TRAD = $(ACC)
 ACC_WARN_YES = 
 ACC_WARN_NO =  -w
@@ -24,6 +31,10 @@ ACC_SFLAGS_YES = -Bstatic
 ACC_SFLAGS_NO=
 ACC_SLIBS_YES =
 ACC_SLIBS_NO=
+ACC_SHRLIB_CFLAGS_YES =  -fPIC
+#ACC_SHRLIB_CFLAGS_YES =  -fPIC -D_BSD_SOURCE
+ACC_SHRLIB_LDFLAGS_YES =  -shared -Wl,-soname,$@ 
+
 
 # Configure OS vendor C++ compiler
 CCC = CC
@@ -40,6 +51,7 @@ CCC_SLIBS_YES =
 CCC_SLIBS_NO=
 CCC_DEPENDS_FLAG = -MM
 
+
 ARCH_DEP_CFLAGS = -D_X86_ -Dlinux
 ARCH_DEP_LDFLAGS =
 
diff --git a/config/CONFIG.Host.UnixCommon b/config/CONFIG.Host.UnixCommon
index 215534066..2246bb2a8 100644
--- a/config/CONFIG.Host.UnixCommon
+++ b/config/CONFIG.Host.UnixCommon
@@ -13,24 +13,23 @@
 LIBNAME = $(LIBRARY:%=lib%.a)
 
 #-------------------------------------------------------
-#     EPICS libs that we need to link the DLL with
-DLL_DEPLIBS = $(DLL_LIBS:%=$(firstword $(%_DIR) $(EPICS_BASE_LIB))/lib%.a)
-DLL_LDLIBS = $(DLL_DEPLIBS) $(SYS_PROD_LIBS:%=lib%.a) $(OP_SYS_LDLIBS)
-  $(ARCH_DEP_LDLIBS)
+# Shared library definitions
 
-#-------------------------------------------------------
-#	A NOOP on all UNIX systems that dont implement
-#	shared libraries
-#
-#DLLNAME = lib$(LIBRARY).???
-LINK.dll = echo share lib build for UNIX archictecture is a NOOP
+# CONFIG.Host.<arch> files may override
+SHRLIB_SUFFIX = .so
+SHRLIB_VERSION = .$(EPICS_VERSION).$(EPICS_REVISION)
+
+SHRLIBNAME = lib$(LIBRARY)$(SHRLIB_SUFFIX)$(SHRLIB_VERSION)
+SHRLIB_CFLAGS = $($(ANSI)_SHRLIB_CFLAGS_$(SHARED_LIBRARIES))
+SHRLIB_LDFLAGS = $($(ANSI)_SHRLIB_LDFLAGS_$(SHARED_LIBRARIES))
+
+LINK.dll= $(SHRLIB_LINKER) -o $@ $(CFLAGS) $(CPPFLAGS) $(SHRLIB_LDFLAGS) $(LDFLAGS)
 
 #-------------------------------------------------------
 # Unix command definitions
 
 CPP = cpp
 RANLIB = ranlib
-LD = ld -r
 
 # GNU compilers
 GCC = gcc
diff --git a/config/CONFIG.Host.alpha b/config/CONFIG.Host.alpha
index ef1af0a5b..f7d687d1c 100644
--- a/config/CONFIG.Host.alpha
+++ b/config/CONFIG.Host.alpha
@@ -23,6 +23,8 @@ ACC_SFLAGS_YES= -non_shared
 ACC_SFLAGS_NO= -call_shared
 ACC_SLIBS_YES =
 ACC_SLIBS_NO=
+ACC_SHRLIB_CFLAGS_YES =
+ACC_SHRLIB_LDFLAGS_YES =
 
 # Configure OS vendor C++ compiler
 CCC = cxx
diff --git a/config/CONFIG.Host.cygwin32 b/config/CONFIG.Host.cygwin32
index 3753d019e..4d412102c 100644
--- a/config/CONFIG.Host.cygwin32
+++ b/config/CONFIG.Host.cygwin32
@@ -22,6 +22,6 @@ CPLUSPLUS=
 #OP_SYS_INCLUDES += /usr/local/include/g++
 #==========================
  
-ARCH_DEP_CFLAGS = -DCYGWIN32
+ARCH_DEP_CFLAGS = -DCYGWIN32 -U_WIN32
 ARCH_DEP_LDLIBS = -lm
 
diff --git a/config/CONFIG.Host.hp700 b/config/CONFIG.Host.hp700
index 2af05e410..5409bb85d 100644
--- a/config/CONFIG.Host.hp700
+++ b/config/CONFIG.Host.hp700
@@ -7,6 +7,8 @@ ARCH_CLASS = hp700
 
 # Include definitions common to all Unix archs
 include $(EPICS_BASE)/config/CONFIG.Host.UnixCommon
+
+SHRLIB_SUFFIX = .sl
  
 AR = ar
 
@@ -23,6 +25,8 @@ ACC_SFLAGS_YES= -Wl,-a,archive
 ACC_SFLAGS_NO=
 ACC_SLIBS_YES =
 ACC_SLIBS_NO=
+ACC_SHRLIB_CFLAGS_YES = +Z
+ACC_SHRLIB_LDFLAGS_YES = -b
 
 # Configure OS vendor C++ compiler
 HPCC = cc 
@@ -37,6 +41,8 @@ HPCC_SFLAGS_YES= -Wl,-a,archive
 HPCC_SFLAGS_NO=
 HPCC_SLIBS_YES =
 HPCC_SLIBS_NO=
+HPCC_SHRLIB_CFLAGS_YES = +Z
+HPCC_SHRLIB_LDFLAGS_YES = -b
 
 CCC = CC
 CCC_NORMAL = $(CCC) +p
diff --git a/config/CONFIG.Host.sgi b/config/CONFIG.Host.sgi
index a780704d1..6d5f582f7 100644
--- a/config/CONFIG.Host.sgi
+++ b/config/CONFIG.Host.sgi
@@ -23,6 +23,8 @@ ACC_SFLAGS_YES= -Bstatic
 ACC_SFLAGS_NO=
 ACC_SLIBS_YES =
 ACC_SLIBS_NO=
+ACC_SHRLIB_CFLAGS_YES =  -KPIC
+ACC_SHRLIB_LDFLAGS_YES =  -shared
 
 # Configure OS vendor C++ compiler
 CCC = CC
diff --git a/config/CONFIG.Host.solaris b/config/CONFIG.Host.solaris
index b38499176..85623ebd4 100644
--- a/config/CONFIG.Host.solaris
+++ b/config/CONFIG.Host.solaris
@@ -34,6 +34,8 @@ ACC_SFLAGS_YES= -Bstatic
 ACC_SFLAGS_NO=
 ACC_SLIBS_YES= -lw -lintl -Bdynamic -ldl -Bstatic -lXext -lX
 ACC_SLIBS_NO=
+ACC_SHRLIB_CFLAGS_YES =  -Kpic -D_REENTRANT 
+ACC_SHRLIB_LDFLAGS_YES =  -G -h $@
 
 # Configure OS vendor C++ compiler
 CCC = $(SPARCWORKS)/bin/CC
diff --git a/config/CONFIG.Host.sun4 b/config/CONFIG.Host.sun4
index 44235d995..73a701397 100644
--- a/config/CONFIG.Host.sun4
+++ b/config/CONFIG.Host.sun4
@@ -34,6 +34,8 @@ ACC_SFLAGS_NO=
 ACC_SLIBS_YES=
 ACC_SLIBS_NO=
 #ACC_OP_SYS_LDFLAGS = -L$(SPECIAL_LANG)
+ACC_SHRLIB_CFLAGS_YES =  -pic
+ACC_SHRLIB_LDFLAGS_YES =  -assert pure-text -h $@
 
 SUNCC = cc
 SUNCC_ANSI = echo SUNCC_ANSI not defined
@@ -47,6 +49,8 @@ SUNCC_SFLAGS_YES= -Bstatic
 SUNCC_SFLAGS_NO=
 SUNCC_SLIBS_YES=
 SUNCC_SLIBS_NO=
+SUNCC_SHRLIB_CFLAGS_YES =  -pic
+SUNCC_SHRLIB_LDFLAGS_YES =  -assert pure-text -h $@
 
 # Configure OS vendor C++ compiler
 CCC = /usr/lang/CC
diff --git a/config/CONFIG_SITE b/config/CONFIG_SITE
index ccc91f8d4..65da7e39e 100644
--- a/config/CONFIG_SITE
+++ b/config/CONFIG_SITE
@@ -97,7 +97,16 @@ CMPLR=STRICT
 #   NORMAL -  ANSI C++ optional warning flags
 #   Individual Makefiles may override
 CXXCMPLR=STRICT
- 
+
+#  Build shared libraries? (Unix type Host builds only)
+#  (archive libraries will also be built)
+#        must be either YES or NO
+#
+#     NOTE solaris and sun4: If YES then LD_LIBRARY_PATH must
+#     include $(INSTALL_LOCATION)/lib/$(HOST_ARCH) both
+#     for the base build and when invoking base executables
+SHARED_LIBRARIES=NO
+
 #  Build client objects statically ?
 #        must be either YES or NO
 STATIC_BUILD=NO
diff --git a/config/RULES.Host b/config/RULES.Host
index 5cc4410db..5f043cb0b 100644
--- a/config/RULES.Host
+++ b/config/RULES.Host
@@ -230,6 +230,7 @@ INCREC +=$(RECTYPES) $(MENUS)
 
 INSTALL_PROD= $(PROD:%= $(INSTALL_BIN)/%)
 INSTALL_LIBS= $(LIBNAME:%=$(INSTALL_LIB)/%)
+INSTALL_SHRLIBS= $(SHRLIBNAME:%=$(INSTALL_LIB)/%)
 INSTALL_DLLS=$(DLLNAME:%=$(INSTALL_BIN)/%)
 INSTALL_TCLLIBS=$(TCLLIBNAME:%=$(INSTALL_TCLLIB)/%)
 INSTALL_TCLINDEX=$(TCLINDEX:%=$(INSTALL_TCLLIB)/%)
@@ -266,12 +267,20 @@ DIRECTORY_TARGETS = $(INSTALL_INCLUDE) $(INSTALL_INCLUDE)/os \
 	$(INSTALL_LOCATION_BIN) $(INSTALL_BIN) $(INSTALL_LIB) \
 	$(INSTALL_LOCATION_LIB) $(INSTALL_CONFIG) \
 	$(MAN_DIRECTORY_TARGETS) $(INSTALL_MAN) \
-	$(INSTALL_TEMPLATES) 
+	$(INSTALL_TEMPLATES)
 
 ifdef TEMPLATES_DIR
 DIRECTORY_TARGETS += $(INSTALL_TEMPLATES)/$(TEMPLATES_DIR)
 endif
 
+#---------------------------------------------------------------
+# must use c++ linker if linking to shared libs with c++ code
+ifeq ($(strip $(SHARED_LIBRARIES)),YES)
+ifneq ($(strip $(CPLUSPLUS)),)
+LINK.c = $(LINK.cc)
+endif # CPLUSPLUS
+endif # LIBTYPE
+
 #---------------------------------------------------------------
 #	if there are no objects LIBOBJS to include
 #	in this library (may be for e.g. base/src/libCompat
@@ -279,31 +288,35 @@ endif
 ifdef LIBRARY
 ifdef LIBOBJS
 LIBTARGETS = $(INSTALL_LOCATION_LIB) $(INSTALL_LIB)
-#	check if DLL or plain lib requested:
-ifeq ($(LIBTYPE),SHARED)
+LIBTARGETS += $(LIBNAME) $(INSTALL_LIBS)
+
+#	check if DLL or plain lib requested: (Win32 build)
+ifeq ($(strip $(LIBTYPE)),SHARED)
 #
 # LIBTYPE=="SHARED" indicates build
 # DLL and also build object archive library
 #
-LIBTARGETS += $(DLLNAME) $(INSTALL_DLLS) $(LIBNAME) $(INSTALL_LIBS)
-else # LIBTYPE=SHARED
-#
-# otherwise build only object archive library
-#
-LIBTARGETS += $(LIBNAME) $(INSTALL_LIBS)
+LIBTARGETS += $(DLLNAME) $(INSTALL_DLLS)
 endif # LIBTYPE=SHARED
+
+#  check if shared library requested: (Unix type build)
+ifeq ($(strip $(SHARED_LIBRARIES)),YES)
+CFLAGS += $(SHRLIB_CFLAGS)
+CXXFLAGS += $(SHRLIB_CFLAGS)
+ifeq ($(findstring cc,$(suffix $(LIBSRCS))),cc)
+SHRLIB_LINKER = $(CXX)
+else
+SHRLIB_LINKER = $(CC)
+endif
+LIBTARGETS += $(SHRLIBNAME) $(INSTALL_SHRLIBS)
+endif # SHARED_LIBRARIES=YES
+
 endif # LIBOBJS
-
-#
-# by default the libraries used when linking the DLL are just
-# PROD_LIBS ans SYS_PROD_LIBS minus the DLL name
-DLL_LIBS = $(subst $(LIBRARY),, $(PROD_LIBS))
-
 endif # LIBRARY
 
 #---------------------------------------------------------------
 #	Main targets
-#
+
 all::	install
 
 build:: $(LIBTARGETS) $(PROD) $(TESTPROD) \
@@ -418,6 +431,7 @@ $(TESTPROD): $(TESTPROD_OBJS) $(PRODDEPLIBS)
 	$(TESTPROD_LINKER) $(TESTPROD_OBJS) $(LDLIBS)
 endif
 
+
 #---------------------------------------------------------------
 #	Generic Rules for 'simple' targets that
 #	can be generated from a single source with same basename.
@@ -569,6 +583,9 @@ $(DBDNAME): ../$(DBDEXPAND)
 $(DLLNAME): $(LIBOBJS)
 	$(LINK.dll) $(LIBOBJS) $(DLL_LDLIBS)
 
+$(SHRLIBNAME): $(LIBOBJS)
+	$(LINK.dll) $(LIBOBJS)
+
 # rule for lib (archive of object files) creation
 $(LIBNAME): $(LIBOBJS)
 	$(RM) $@
@@ -600,6 +617,14 @@ $(INSTALL_LIB)/%.lib: %.lib
 	@echo "Installing library $@"
 	@$(INSTALL) -m 644 $< $(INSTALL_LIB)
 
+$(INSTALL_SHRLIBS): $(SHRLIBNAME)
+	@echo "Installing library $@"
+	$(INSTALL) -m 644 $< $(INSTALL_LIB)
+ifdef SHRLIB_VERSION
+	$(RM) $(subst $(SHRLIB_VERSION),,$@)
+	ln -s $< $(subst $(SHRLIB_VERSION),,$@)
+endif # SHRLIB_VERSION
+
 $(INSTALL_TCLLIB)/%: %
 	@echo "Installing Tcl library $@"
 	@$(INSTALL) -m 555 $< $(INSTALL_TCLLIB)