diff --git a/.gitignore b/.gitignore
index 4fcd01f..54ee763 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,6 @@
 build/
+build-static/
+build-shared/
 vxi11.h
 vxi11_cmd
 vxi11_clnt.c
@@ -8,7 +10,9 @@ TAGS
 vxi11_test.cc
 vxi11_test.cc
 docs
-libvxi11.so.0
+libvxi11.a
+libvxi11.so
+libvxi11.so.*
 vxi11_send
 *.o
 *.pyc
diff --git a/Makefile b/Makefile
index 7761e9e..e28bf8c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-VERSION=2.0
+VERSION=2.1
 
 include config.mk
 
diff --git a/library/Makefile b/library/Makefile
index 881b419..f9d7bd2 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -1,6 +1,6 @@
 include ../config.mk
 
-.PHONY : all install clean dist distclean
+.PHONY : all static shared install clean dist distclean
 
 UNAME:=$(shell uname -s)
 
@@ -8,31 +8,45 @@ ifneq ($(UNAME),SunOS)
 	LDFLAGS:=$(LDFLAGS) -Wl,--version-script=linker.version
 endif
 
-all : libvxi11.so.${SOVERSION}
+OBJ:=vxi11_user.o vxi11_clnt.o vxi11_xdr.o
+SDIR:=build-static
+DDIR:=build-shared
 
-libvxi11.so.${SOVERSION} : vxi11_user.o vxi11_clnt.o vxi11_xdr.o
+all : static shared
+static : libvxi11.a
+shared : libvxi11.so
+
+libvxi11.so : libvxi11.so.${SOVERSION}
+	ln -sf libvxi11.so.${SOVERSION} libvxi11.so
+
+libvxi11.so.${SOVERSION} : $(addprefix ${DDIR}/,${OBJ})
 	$(CC) $(LDFLAGS) -shared -Wl,-soname,libvxi11.so.${SOVERSION} $^ -o $@
 
-vxi11_user.o: vxi11_user.c vxi11.h
-	$(CC) -fPIC $(CFLAGS) -c $< -o $@
+libvxi11.a : $(addprefix ${SDIR}/,${OBJ})
+	$(AR) rcs $@ $^
 
-vxi11_clnt.o : vxi11_clnt.c
+${DDIR}/%.o : %.c vxi11.h | ${DDIR}
 	$(CC) -fPIC $(CFLAGS) -c $< -o $@
 
-vxi11_xdr.o : vxi11_xdr.c
-	$(CC) -fPIC $(CFLAGS) -c $< -o $@
+${SDIR}/%.o : %.c vxi11.h | ${SDIR}
+	$(CC) $(CFLAGS) -c $< -o $@
 
 vxi11.h vxi11_clnt.c vxi11_xdr.c : vxi11.x
 	rpcgen -M vxi11.x
 
+${SDIR} ${DDIR}:
+	@mkdir $@
+
 TAGS: $(wildcard *.c) $(wildcard *.h) $(wildcard *.c)
 	etags $^
 
 clean:
-	rm -f *.o libvxi11.so.${SOVERSION} vxi11.h vxi11_svc.c vxi11_xdr.c vxi11_clnt.c TAGS
+	rm -rf ${SDIR} ${DDIR}
+	rm -f *.o libvxi11.so libvxi11.so.${SOVERSION} libvxi11.a vxi11.h vxi11_svc.c vxi11_xdr.c vxi11_clnt.c TAGS
 
 install: all
 	$(INSTALL) -d $(DESTDIR)$(prefix)/lib${LIB_SUFFIX}/
+	$(INSTALL) libvxi11.a $(DESTDIR)$(prefix)/lib${LIB_SUFFIX}/
 	$(INSTALL) libvxi11.so.${SOVERSION} $(DESTDIR)$(prefix)/lib${LIB_SUFFIX}/
 	ln -sf libvxi11.so.${SOVERSION} $(DESTDIR)$(prefix)/lib${LIB_SUFFIX}/libvxi11.so
 	$(INSTALL) -d $(DESTDIR)$(prefix)/include/
diff --git a/library/linker.version b/library/linker.version
index 3d9c829..4b9a8e4 100644
--- a/library/linker.version
+++ b/library/linker.version
@@ -2,15 +2,17 @@
  * symbols are exported.
  */
 
-VXI11_2.0 {
+VXI11_2.1 {
 	global:
 		vxi11_close_device;
+		vxi11_close_device_clients;
 		vxi11_lib_version;
 		vxi11_obtain_double_value;
 		vxi11_obtain_double_value_timeout;
 		vxi11_obtain_long_value;
 		vxi11_obtain_long_value_timeout;
 		vxi11_open_device;
+		vxi11_open_device_clients;
 		vxi11_receive;
 		vxi11_receive_data_block;
 		vxi11_receive_timeout;
diff --git a/library/vxi11_user.c b/library/vxi11_user.c
index de216ed..046f899 100644
--- a/library/vxi11_user.c
+++ b/library/vxi11_user.c
@@ -63,16 +63,7 @@ struct _VXI11_CLINK {
  *   with the same address or not
  */
 
-struct _vxi11_client_t {
-	struct _vxi11_client_t *next;
-	char address[20];
-#ifndef WIN32
-	CLIENT *client_address;
-#endif
-	int link_count;
-};
-
-static struct _vxi11_client_t *VXI11_CLIENTS = NULL;
+static vxi11_client_t *VXI11_CLIENTS = NULL;
 
 /* Internal function declarations. */
 static int _vxi11_open_link(VXI11_CLINK * clink, const char *address,
@@ -99,13 +90,18 @@ int vxi11_lib_version(int *major, int *minor, int *revision)
 /* Use this function from user land to open a device and create a link. Can be
  * used multiple times for the same device (the library will keep track).*/
 int vxi11_open_device(VXI11_CLINK **clink, const char *address, char *device)
+{
+    return vxi11_open_device_clients(clink, address, device, &VXI11_CLIENTS);
+}
+
+int vxi11_open_device_clients(VXI11_CLINK **clink, const char *address, char *device, vxi11_client_t **clients)
 {
 #ifdef WIN32
 	ViStatus status;
 	char buf[256];
 #else
 	int ret;
-	struct _vxi11_client_t *tail, *client = NULL;
+	vxi11_client_t *tail, *client = NULL;
 #endif
 	char default_device[6] = "inst0";
 	char *use_device;
@@ -141,7 +137,7 @@ int vxi11_open_device(VXI11_CLINK **clink, const char *address, char *device)
 #else
 	/* Have a look to see if we've already initialised an instrument with
 	 * this address */
-	tail = VXI11_CLIENTS;
+	tail = *clients;
 	while (tail) {
 		if (strcmp(address, tail->address) == 0) {
 			client = tail;
@@ -156,7 +152,7 @@ int vxi11_open_device(VXI11_CLINK **clink, const char *address, char *device)
 		 * is, for this address. Because it's a new client, this
 		 * must be link number 1. Keep track of how many devices we've
 		 * opened so we don't run out of storage space. */
-		client = (struct _vxi11_client_t *)calloc(1, sizeof(struct _vxi11_client_t));
+		client = (vxi11_client_t *)calloc(1, sizeof(vxi11_client_t));
 		if (!client) {
 			free(*clink);
 			*clink = NULL;
@@ -186,8 +182,8 @@ int vxi11_open_device(VXI11_CLINK **clink, const char *address, char *device)
 		strncpy(client->address, address, 20);
 		client->client_address = (*clink)->client;
 		client->link_count = 1;
-		client->next = VXI11_CLIENTS;
-		VXI11_CLIENTS = client;
+		client->next = *clients;
+		*clients = client;
 	} else {
 		/* Copy the client pointer address. Just establish a new link
 		 *  not a new client). Add one to the link count */
@@ -205,16 +201,21 @@ int vxi11_open_device(VXI11_CLINK **clink, const char *address, char *device)
 /* Use this function from user land to close a device and/or sever a link. Can
  * be used multiple times for the same device (the library will keep track).*/
 int vxi11_close_device(VXI11_CLINK * clink, const char *address)
+{
+    return vxi11_close_device_clients(clink, address, &VXI11_CLIENTS);
+}
+
+int vxi11_close_device_clients(VXI11_CLINK * clink, const char *address, vxi11_client_t **clients)
 {
 	int ret = 0;
 #ifdef WIN32
 	viClose(clink->session);
 	viClose(clink->rm);
 #else
-	struct _vxi11_client_t *tail, *last = NULL, *client = NULL;
+	vxi11_client_t *tail, *last = NULL, *client = NULL;
 
 	/* Which instrument are we referring to? */
-	tail = VXI11_CLIENTS;
+	tail = *clients;
 	while (tail) {
 		if (strncmp(address, tail->address, 20) == 0) {
 			client = tail;
@@ -245,7 +246,7 @@ int vxi11_close_device(VXI11_CLINK * clink, const char *address)
 			if (last) {
 				last->next = client->next;
 			} else {
-				VXI11_CLIENTS = client->next;
+				*clients = client->next;
 			}
 		}
 	}
diff --git a/library/vxi11_user.h b/library/vxi11_user.h
index 1a2e042..84fcc79 100644
--- a/library/vxi11_user.h
+++ b/library/vxi11_user.h
@@ -41,10 +41,11 @@ extern "C" {
 #endif
 
 #include <stdlib.h>
+#include <rpc/rpc.h>
 
 
 #define LIBVXI11_MAJOR 2
-#define LIBVXI11_MINOR 0
+#define LIBVXI11_MINOR 1
 #define LIBVXI11_REVISION 0
 /* LIBVXI11_VERSION_NUMBER looks like 2002001 for e.g. version 2.2.1. */
 #define LIBVXI11_VERSION_NUMBER (LIBVXI11_MAJOR*1000000+LIBVXI11_MINOR*1000+LIBVXI11_REVISION)
@@ -65,6 +66,15 @@ typedef	struct _VXI11_CLINK VXI11_CLINK;
 /* vxi11_send() return value if a sent command times out ON THE INSTRUMENT. */
 #define	VXI11_NULL_WRITE_RESP	51
 
+/* client list stucture */
+typedef struct _vxi11_client_t {
+    struct _vxi11_client_t *next;
+    char address[20];
+#ifndef WIN32
+    CLIENT *client_address;
+#endif
+    int link_count;
+} vxi11_client_t;
 
 /* Function: vxi11_library_version
  *
@@ -105,6 +115,27 @@ vx_EXPORT int vxi11_lib_version(int *major, int *minor, int *revision);
 vx_EXPORT int vxi11_open_device(VXI11_CLINK **clink, const char *address, char *device);
 
 
+/* Function: vxi11_open_device_clients
+ *
+ * Open a connection to an instrument.
+ *
+ * Parameters:
+ *  clink   - pointer to a VXI11_CLINK pointer, will be initialised on a
+ *            successful connection.
+ *  address - the IP address or (where supported) USB address for the
+ *            instrument to connect to.
+ *  device   - some instruments have multiple interfaces, this allows you to
+ *            specify which to connect to. Set to NULL to use the default of
+ *            "inst0".
+ *  clients  - pointer to a vxi11_clients structure
+ *
+ * Returns:
+ *  0 - on success
+ *  1 - on failure. clink will not be a valid pointer.
+ */
+vx_EXPORT int vxi11_open_device_clients(VXI11_CLINK **clink, const char *address, char *device, vxi11_client_t **clients);
+
+
 /* Function: vxi11_close_device
  *
  * Parameters:
@@ -118,6 +149,20 @@ vx_EXPORT int vxi11_open_device(VXI11_CLINK **clink, const char *address, char *
 vx_EXPORT int vxi11_close_device(VXI11_CLINK *clink, const char *address);
 
 
+/* Function: vxi11_close_device_clients
+ *
+ * Parameters:
+ *  clink   - a valid VXI11_CLINK pointer.
+ *  address - the IP address or (where supported) USB address for the
+ *            instrument.
+ *  clients  - pointer to a vxi11_clients structure
+ *
+ * Returns:
+ *  0 - on success
+ */
+vx_EXPORT int vxi11_close_device_clients(VXI11_CLINK *clink, const char *address, vxi11_client_t **clients);
+
+
 /* Function: vxi11_send
  *
  * Send data to an instrument.
diff --git a/utils/Makefile b/utils/Makefile
index d73a8f7..c30f067 100644
--- a/utils/Makefile
+++ b/utils/Makefile
@@ -3,19 +3,14 @@ include ../config.mk
 .PHONY : all install clean
 
 CFLAGS:=${CFLAGS} -I../library
+LDFLAGS:=${LDFLAGS} -L../library -lvxi11
 
 all : vxi11_cmd vxi11_send
 
-vxi11_cmd: vxi11_cmd.o ../library/libvxi11.so.${SOVERSION}
+vxi11_cmd vxi11_send: %: %.o
 	$(CC) -o $@ $^ $(LDFLAGS)
 
-vxi11_cmd.o: vxi11_cmd.c ../library/vxi11_user.c ../library/vxi11.h
-	$(CC) $(CFLAGS) -c $< -o $@
-
-vxi11_send: vxi11_send.o ../library/libvxi11.so.${SOVERSION}
-	$(CC) -o $@ $^ $(LDFLAGS)
-
-vxi11_send.o: vxi11_send.c ../library/vxi11_user.c ../library/vxi11.h
+%.o: %.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
 clean: