diff --git a/Contrib/ExDLL/exdll.h b/Contrib/ExDLL/exdll.h
new file mode 100644
index 00000000..38083e1d
--- /dev/null
+++ b/Contrib/ExDLL/exdll.h
@@ -0,0 +1,87 @@
+#ifndef _EXDLL_H_
+#define _EXDLL_H_
+
+// only include this file from one place in your DLL.
+// (it is all static shit, if you use it in two places it will fail)
+
+#define EXDLL_INIT()           {  \
+        g_stringsize=string_size; \
+        g_stacktop=stacktop;      \
+        g_variables=variables; }
+
+
+typedef struct _stack_t {
+  struct _stack_t *next;
+  char text[1]; // this should be the length of string_size
+} stack_t;
+
+
+static int g_stringsize;
+static stack_t **g_stacktop;
+static char *g_variables;
+
+static int popstring(char *str); // 0 on success, 1 on empty stack
+static void pushstring(char *str);
+
+enum
+{
+INST_0,         // $0
+INST_1,         // $1
+INST_2,         // $2
+INST_3,         // $3
+INST_4,         // $4
+INST_5,         // $5
+INST_6,         // $6
+INST_7,         // $7
+INST_8,         // $8
+INST_9,         // $9
+INST_R0,        // $R0
+INST_R1,        // $R1
+INST_R2,        // $R2
+INST_R3,        // $R3
+INST_R4,        // $R4
+INST_R5,        // $R5
+INST_R6,        // $R6
+INST_R7,        // $R7
+INST_R8,        // $R8
+INST_R9,        // $R9
+INST_CMDLINE,   // $CMDLINE
+INST_INSTDIR,   // $INSTDIR
+INST_OUTDIR,    // $OUTDIR
+INST_EXEDIR,    // $EXEDIR
+INST_LANG,      // $LANGUAGE
+__INST_LAST
+};
+
+
+// utility functions (not required but often useful)
+static int popstring(char *str)
+{
+  stack_t *th;
+  if (!g_stacktop || !*g_stacktop) return 1;
+  th=(*g_stacktop);
+  lstrcpy(str,th->text);
+  *g_stacktop = th->next;
+  GlobalFree((HGLOBAL)th);
+  return 0;
+}
+
+static void pushstring(char *str)
+{
+  stack_t *th;
+  if (!g_stacktop) return;
+  th=(stack_t*)GlobalAlloc(GPTR,sizeof(stack_t)+g_stringsize);
+  lstrcpyn(th->text,str,g_stringsize);
+  th->next=*g_stacktop;
+  *g_stacktop=th;
+}
+
+static char *getuservariable(int varnum)
+{
+  if (varnum < 0 || varnum >= __INST_LAST) return NULL;
+  return g_variables+varnum*g_stringsize;
+}
+
+
+
+#endif//_EXDLL_H_
\ No newline at end of file