diff --git a/ADOL-C/boost-test/CMakeLists.txt b/ADOL-C/boost-test/CMakeLists.txt
index 6daa6f40..137d40de 100644
--- a/ADOL-C/boost-test/CMakeLists.txt
+++ b/ADOL-C/boost-test/CMakeLists.txt
@@ -25,6 +25,7 @@ set(SOURCE_FILES
     traceSecOrderScalar.cpp
     traceSecOrderVector.cpp
     traceFixedPointScalarTests.cpp
+    uni5_for.cpp
     )
 add_executable(boost-test-adolc ${SOURCE_FILES})
 target_include_directories(boost-test-adolc PRIVATE "${ADOLC_INCLUDE_DIR}")
diff --git a/ADOL-C/boost-test/uni5_for.cpp b/ADOL-C/boost-test/uni5_for.cpp
new file mode 100644
index 00000000..593ec756
--- /dev/null
+++ b/ADOL-C/boost-test/uni5_for.cpp
@@ -0,0 +1,85 @@
+
+/*
+File for explicit testing functions from uni5_for.c file.
+*/
+
+#define BOOST_TEST_DYN_LINK
+#include <boost/test/unit_test.hpp>
+
+namespace tt = boost::test_tools;
+
+#include <adolc/adolc.h>
+
+#include "const.h"
+
+#include <array>
+#include <numeric>
+#include <vector>
+
+BOOST_AUTO_TEST_SUITE(uni5_for)
+
+BOOST_AUTO_TEST_CASE(ZOS_PL_FORWARD) {
+
+  enableMinMaxUsingAbs();
+
+  const int16_t tag = 1;
+
+  const int dim_out = 1;
+  const int dim_in = 3;
+
+  std::array<double, dim_in> in = {-2.0, 0.0, 1.5};
+  std::array<adouble, dim_in> indep;
+  double out[] = {0.0};
+
+  // ---------------------- trace on ---------------------
+  // function is given by fabs(in_2 + fabs(in_1 + fabs(in_0)))
+  trace_on(tag);
+
+  // init independents
+  std::for_each(in.begin(), in.end(), [&, i = 0](int value) mutable {
+    indep[i] <<= in[i];
+    ++i;
+  });
+
+  // fabs(in_2 + fabs(in_1 + fabs(in_0)))
+  adouble dep =
+      std::accumulate(indep.begin(), indep.end(), adouble(0.0),
+                      [](adouble sum, adouble val) { return fabs(sum + val); });
+
+  dep >>= out[0];
+  trace_off();
+
+  // ---------------------- trace off ---------------------
+
+  // test outout
+  double test_out =
+      std::accumulate(in.begin(), in.end(), 0.0, [](double sum, double val) {
+        return std::fabs(sum + val);
+      });
+  BOOST_TEST(out[0] == test_out, tt::tolerance(tol));
+
+  // test num switches
+  int num_switches = get_num_switches(tag);
+  BOOST_TEST(num_switches == dim_in, tt::tolerance(tol));
+
+  const int keep = 0;
+  std::vector<double> switching_vec(num_switches);
+  zos_pl_forward(tag, dim_out, dim_in, keep, in.data(), out,
+                 switching_vec.data());
+
+  // test outout of zos_pl_forward
+  BOOST_TEST(out[0] == test_out, tt::tolerance(tol));
+
+  // test switching vector
+  std::vector<double> test_switching_vec(num_switches);
+  test_switching_vec[0] = in[0];
+  for (std::size_t i = 1; i < num_switches; ++i) {
+    test_switching_vec[i] = std::fabs(test_switching_vec[i - 1]) + in[i];
+  }
+  BOOST_CHECK_EQUAL_COLLECTIONS(switching_vec.begin(), switching_vec.end(),
+                                test_switching_vec.begin(),
+                                test_switching_vec.end());
+
+  removeTape(tag, ADOLC_REMOVE_COMPLETELY);
+}
+BOOST_AUTO_TEST_SUITE_END()
\ No newline at end of file
diff --git a/ADOL-C/src/taping.c b/ADOL-C/src/taping.c
index 7972dce2..6451952e 100644
--- a/ADOL-C/src/taping.c
+++ b/ADOL-C/src/taping.c
@@ -1344,6 +1344,10 @@ void freeTapeResources(TapeInfos *tapeInfos) {
     fclose(tapeInfos->tay_file);
     tapeInfos->tay_file = NULL;
   }
+  if (tapeInfos->signature != NULL) {
+    free(tapeInfos->signature);
+    tapeInfos->signature = NULL;
+  }
 }
 
 /****************************************************************************/
diff --git a/ADOL-C/src/uni5_for.c b/ADOL-C/src/uni5_for.c
index 2368a031..10c73200 100644
--- a/ADOL-C/src/uni5_for.c
+++ b/ADOL-C/src/uni5_for.c
@@ -933,9 +933,6 @@ int hov_forward(
 #endif
 
   locint switchnum = 0;
-#if !defined(_NTIGHT_)
-  double *signature = NULL;
-#endif
 
   /* extern diff. function variables */
 #if defined(_EXTERN_)
@@ -1097,13 +1094,10 @@ int hov_forward(
   dp_T0 = myalloc1(ADOLC_CURRENT_TAPE_INFOS.stats[NUM_MAX_LIVES]);
   ADOLC_CURRENT_TAPE_INFOS.dp_T0 = dp_T0;
 
-  if (ADOLC_CURRENT_TAPE_INFOS.stats[NO_MIN_MAX]) {
-    if (ADOLC_CURRENT_TAPE_INFOS.signature == NULL) {
-      signature = myalloc1(ADOLC_CURRENT_TAPE_INFOS.stats[NUM_SWITCHES]);
-      ADOLC_CURRENT_TAPE_INFOS.signature = signature;
-    } else
-      signature = ADOLC_CURRENT_TAPE_INFOS.signature;
-  }
+  if ((ADOLC_CURRENT_TAPE_INFOS.stats[NO_MIN_MAX]) &&
+      (ADOLC_CURRENT_TAPE_INFOS.signature == NULL))
+    ADOLC_CURRENT_TAPE_INFOS.signature =
+        myalloc1(ADOLC_CURRENT_TAPE_INFOS.stats[NUM_SWITCHES]);
 
   ADOLC_CURRENT_TAPE_INFOS.dpp_T = &dp_T0;
   ADOLC_CURRENT_TAPE_INFOS.numTay = 0;
@@ -4283,7 +4277,7 @@ int hov_forward(
           MINDEC(ret_c, 2);
       }
       if (ADOLC_CURRENT_TAPE_INFOS.stats[NO_MIN_MAX]) {
-        signature[switchnum] = dp_T0[arg];
+        ADOLC_CURRENT_TAPE_INFOS.signature[switchnum] = dp_T0[arg];
 #if defined(_ABS_NORM_) || defined(_ABS_NORM_SIG_)
         swargs[switchnum] = dp_T0[arg];
 #endif