Index: impedance.c
===================================================================
--- impedance.c	(revision 31761)
+++ impedance.c	(revision 31762)
@@ -26,6 +26,10 @@
 
 #include "config.h"
 #include <math.h>
+#include <librnd/core/misc_util.h>
+#include <librnd/core/math_helper.h>
+#include <librnd/core/actions.h>
+#include "impedance.h"
 
 #define TOM(x) RND_COORD_TO_MM(x)
 #define SQR(x) ((x)*(x))
@@ -42,3 +46,21 @@
 	return N0 / (2*M_PI * sqrt(2) * sqrt(Er+1)) * log(1+4*(h/weff)*(x1+x2));
 }
 
+
+const char pcb_acts_impedance_microstrip[] = "impedance_microstrip(trace_width, trace_height, subst_height, dielectric)";
+const char pcb_acth_impedance_microstrip[] = "Calculate the approximated impedance of a microstrip transmission line, in ohms";
+fgw_error_t pcb_act_impedance_microstrip(fgw_arg_t *res, int argc, fgw_arg_t *argv)
+{
+	rnd_coord_t trace_width, trace_height, subst_height;
+	double dielectric;
+
+	RND_ACT_CONVARG(1, FGW_KEYWORD, impedance_microstrip, trace_width = fgw_coord(&argv[1]));
+	RND_ACT_CONVARG(2, FGW_KEYWORD, impedance_microstrip, trace_height = fgw_coord(&argv[2]));
+	RND_ACT_CONVARG(3, FGW_KEYWORD, impedance_microstrip, subst_height = fgw_coord(&argv[3]));
+	RND_ACT_CONVARG(4, FGW_KEYWORD, impedance_microstrip, dielectric = argv[4].val.nat_double);
+
+	res->type = FGW_DOUBLE;
+	res->val.nat_double = pcb_impedance_microstrip(trace_width, trace_height, subst_height, dielectric);
+	return 0;
+}
+
Index: impedance.h
===================================================================
--- impedance.h	(revision 31761)
+++ impedance.h	(revision 31762)
@@ -1,2 +1,7 @@
+#include <librnd/core/actions.h>
+
 double pcb_impedance_microstrip(rnd_coord_t trace_width, rnd_coord_t trace_height, rnd_coord_t subst_height, double dielect);
 
+extern const char pcb_acts_impedance_microstrip[];
+extern const char pcb_acth_impedance_microstrip[];
+fgw_error_t pcb_act_impedance_microstrip(fgw_arg_t *res, int argc, fgw_arg_t *argv);
Index: test/config.h
===================================================================
--- test/config.h	(revision 31761)
+++ test/config.h	(nonexistent)
@@ -1,4 +0,0 @@
-typedef int rnd_coord_t;
-
-#define RND_COORD_TO_MM(x) ((x)/1000000)
-#define RND_MM_TO_COORD(x) ((x)*1000000)
Index: test/Makefile
===================================================================
--- test/Makefile	(revision 31761)
+++ test/Makefile	(revision 31762)
@@ -1,6 +1,8 @@
-CFLAGS = -Wall -I.
-LDFLAGS = -lm
-main: main.o
+CFLAGS = -Wall -I. -I../../../src -I../../../src_3rd -I../../..
+LDFLAGS = -lm -ldl
+LIBRND = ../../../src/librnd-hid.a ../../../src/librnd-3rd.a
 
-main.o: main.c ../impedance.c config.h
+main: main.o $(LIBRND)
 
+main.o: main.c ../impedance.c glue.c
+
Index: test/glue.c
===================================================================
--- test/glue.c	(nonexistent)
+++ test/glue.c	(revision 31762)
@@ -0,0 +1,17 @@
+/* glue for hidlib */
+
+#include <librnd/core/hidlib.h>
+
+const char *rnd_menu_file_paths[4];
+const char *rnd_menu_name_fmt = "pcb-menu-%s.lht";
+
+const char *rnd_hidlib_default_embedded_menu = "";
+
+void rnd_hidlib_crosshair_move_to(rnd_hidlib_t *hl, rnd_coord_t abs_x, rnd_coord_t abs_y, int mouse_mot) { }
+
+const char *rnd_conf_userdir_path;
+const char *rnd_pcphl_conf_user_path;
+const char *rnd_conf_sysdir_path;
+const char *rnd_conf_sys_path;
+
+const char pcb_conf_internal_arr[] = {""}, *pcb_conf_internal = pcb_conf_internal_arr;
Index: test/main.c
===================================================================
--- test/main.c	(revision 31761)
+++ test/main.c	(revision 31762)
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include "glue.c"
 #include "../impedance.c"
 int main()
 {