diff --git a/common/alloc.c b/common/alloc.c
index c0e0218b..188c8a66 100644
--- a/common/alloc.c
+++ b/common/alloc.c
@@ -5,4 +5,5 @@
 #include "../sharedbits/alloc_impl.h"
 #include "../sharedbits/array_impl.h"
 #include "../sharedbits/strsafe_impl.h"
+#include "../sharedbits/strdup_impl.h"
 #undef sharedbitsPrefix
diff --git a/common/controls.c b/common/controls.c
index 0b45868f..bf479a6e 100644
--- a/common/controls.c
+++ b/common/controls.c
@@ -198,5 +198,3 @@ void *uiControlImplData(uiControl *c)
 	}
 	return c->implData;
 }
-
-$$
diff --git a/common/uipriv.h b/common/uipriv.h
index 4c195d52..89888cae 100644
--- a/common/uipriv.h
+++ b/common/uipriv.h
@@ -56,6 +56,7 @@ extern bool uiprivSysCheckThread(void);
 #define uiprivArrayFree(arr) uiprivArrayFreeFull(&(arr))
 #define uiprivArrayAt(arr, T, n) (((T *) (arr.buf)) + (n))
 #include "../sharedbits/strsafe_header.h"
+#include "../sharedbits/strdup_header.h"
 #undef sharedbitsPrefix
 
 // errors.c
diff --git a/sharedbits/strdup_header.h b/sharedbits/strdup_header.h
new file mode 100644
index 00000000..0833bbc0
--- /dev/null
+++ b/sharedbits/strdup_header.h
@@ -0,0 +1,8 @@
+// 8 june 2019
+// requires: alloc_header.h
+
+#include "start.h"
+
+extern char *sharedbitsPrefixName(Strdup)(const char *s);
+
+#include "end.h"
diff --git a/sharedbits/strdup_impl.h b/sharedbits/strdup_impl.h
new file mode 100644
index 00000000..76151f00
--- /dev/null
+++ b/sharedbits/strdup_impl.h
@@ -0,0 +1,17 @@
+// 8 june 2019
+// requires alloc_header.h and any of the strsafe_* files
+
+#include "start.h"
+
+char *sharedbitsPrefixName(Strdup)(const char *s)
+{
+	char *t;
+	size_t n;
+
+	n = strlen(s);
+	t = (char *) sharedbitsPrefixName(Alloc)((n + 1) * sizeof (char), "char[]");
+	sharedbitsPrefixName(Strncpy)(t, s, n + 1);
+	return t;
+}
+
+#include "end.h"
diff --git a/test/lib/testingpriv.c b/test/lib/testingpriv.c
index 64fd2658..c9c2e5b7 100644
--- a/test/lib/testingpriv.c
+++ b/test/lib/testingpriv.c
@@ -31,6 +31,12 @@ void testingprivInternalError(const char *fmt, ...)
 #undef sharedbitsStatic
 #undef sharedbitsPrefix
 
+#define sharedbitsPrefix testingpriv
+#define testingprivStrncpy testingprivImplStrncpy
+#include "../../sharedbits/strdup_impl.h"
+#undef testingprivStrncpy
+#undef sharedbitsPrefix
+
 int testingprivVsnprintf(char *s, size_t n, const char *fmt, va_list ap)
 {
 	int ret;
@@ -52,17 +58,6 @@ int testingprivSnprintf(char *s, size_t n, const char *fmt, ...)
 	return ret;
 }
 
-char *testingprivStrdup(const char *s)
-{
-	char *t;
-	size_t n;
-
-	n = strlen(s);
-	t = (char *) testingprivAlloc((n + 1) * sizeof (char), "char[]");
-	testingprivImplStrncpy(t, s, n + 1);
-	return t;
-}
-
 char *testingprivVsmprintf(const char *fmt, va_list ap)
 {
 	char *s;
diff --git a/test/lib/testingpriv.h b/test/lib/testingpriv.h
index f9e41f6f..1021b79f 100644
--- a/test/lib/testingpriv.h
+++ b/test/lib/testingpriv.h
@@ -19,13 +19,14 @@ sharedbitsPrintfFunc(
 #define testingprivArrayFree(arr) testingprivArrayFreeFull(&(arr))
 #define testingprivArrayAt(arr, T, n) (((T *) (arr.buf)) + (n))
 
+#include "../../sharedbits/strdup_header.h"
+
 #undef sharedbitsPrefix
 
 extern int testingprivVsnprintf(char *s, size_t n, const char *fmt, va_list ap);
 sharedbitsPrintfFunc(
 	extern int testingprivSnprintf(char *s, size_t n, const char *fmt, ...),
 	3, 4);
-extern char *testingprivStrdup(const char *s);
 extern char *testingprivVsmprintf(const char *fmt, va_list ap);
 sharedbitsPrintfFunc(
 	extern char *testingprivSmprintf(const char *fmt, ...),