diff --git a/examples/vhdl/external_buffer/run.py b/examples/vhdl/external_buffer/run.py
new file mode 100644
index 0000000000..218bfd0420
--- /dev/null
+++ b/examples/vhdl/external_buffer/run.py
@@ -0,0 +1,51 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# Copyright (c) 2014-2019, Lars Asplund lars.anders.asplund@gmail.com
+
+"""
+External Buffer
+---------------
+
+`Interfacing with foreign languages (C) through VHPIDIRECT <https://ghdl.readthedocs.io/en/latest/using/Foreign.html>`_
+
+An array of type ``uint8_t`` is allocated in a C application and some values
+are written to the first ``1/3`` positions. Then, the VHDL simulation is
+executed, where the (external) array/buffer is used.
+
+In the VHDL testbenches, two vector pointers are created, each of them using
+a different access mechanism (``extfunc`` or ``extacc``). One of them is used to copy
+the first ``1/3`` elements to positions ``[1/3, 2/3)``, while incrementing each value
+by one. The second one is used to copy elements from ``[1/3, 2/3)`` to ``[2/3, 3/3)``,
+while incrementing each value by two.
+
+When the simulation is finished, the C application checks whether data was successfully
+copied/modified. The content of the buffer is printed both before and after the
+simulation.
+"""
+
+from vunit import VUnit
+from os import popen
+from os.path import join, dirname
+
+src_path = join(dirname(__file__), 'src')
+
+c_obj = join(src_path, 'main.o')
+# Compile C application to an object
+print(popen(' '.join([
+    'gcc', '-fPIC',
+    '-c', join(src_path, 'main.c'),
+    '-o', c_obj
+])).read())
+
+# Enable the external feature for strings
+vu = VUnit.from_argv(vhdl_standard='2008', external={'string': True})
+
+lib = vu.add_library('lib')
+lib.add_source_files(join(src_path, '*.vhd'))
+
+# Add the C object to the elaboration of GHDL
+vu.set_sim_option('ghdl.elab_flags', ['-Wl,' + c_obj])
+
+vu.main()
diff --git a/examples/vhdl/external_buffer/src/main.c b/examples/vhdl/external_buffer/src/main.c
new file mode 100644
index 0000000000..8b69fc8f28
--- /dev/null
+++ b/examples/vhdl/external_buffer/src/main.c
@@ -0,0 +1,97 @@
+/*
+External Buffer
+
+Interfacing with foreign languages (C) through VHPIDIRECT:
+https://ghdl.readthedocs.io/en/latest/using/Foreign.html
+
+An array of type uint8_t is allocated and some values are written to the first 1/3
+positions. Then, the VHDL simulation is executed, where the (external) array/buffer
+is used. When the simulation is finished, the results are checked. The content of
+the buffer is printed both before and after the simulation.
+
+NOTE: This file is expected to be used along with tb_ext_byte_vector.vhd or tb_ext_string.vhd
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+extern int ghdl_main (int argc, char **argv);
+
+uint8_t *D[1];
+const uint32_t length = 5;
+
+// Check procedure, to be executed when GHDL exits.
+// The simulation is expected to copy the first 1/3 elements to positions [1/3, 2/3),
+// while incrementing each value by one, and then copy elements from [1/3, 2/3) to
+// [2/3, 3/3), while incrementing each value by two.
+static void exit_handler(void) {
+  int i, j, z, k;
+  uint8_t expected, got;
+  k = 0;
+  for (j=0; j<3; j++) {
+    k += j;
+    for(i=0; i<length; i++) {
+      z = (length*j)+i;
+
+      expected = (i+1)*11 + k;
+      got = D[0][z];
+      if (expected != got) {
+        printf("check error %d: %d %d\n", z, expected, got);
+        exit(1);
+      }
+      printf("%d: %d\n", z, got);
+    }
+  }
+  free(D[0]);
+}
+
+// Main entrypoint of the application
+int main(int argc, char **argv) {
+  // Allocate a buffer which is three times the number of values
+  // that we want to copy/modify
+  D[0] = (uint8_t *) malloc(3*length*sizeof(uint8_t));
+  if ( D[0] == NULL ) {
+    perror("execution of malloc() failed!\n");
+    return -1;
+  }
+  // Initialize the first 1/3 of the buffer
+  int i;
+  for(i=0; i<length; i++) {
+    D[0][i] = (i+1)*11;
+  }
+  // Print all the buffer
+  for(i=0; i<3*length; i++) {
+    printf("%d: %d\n", i, D[0][i]);
+  }
+
+  // Register a function to be called when GHDL exits
+  atexit(exit_handler);
+
+  // Start the simulation
+  return ghdl_main(argc, argv);
+}
+
+// External through access (mode<0)
+
+void set_string_ptr(uint8_t id, uint8_t *p) {
+  //printf("C set_string_ptr(%d, %p)\n", id, p);
+  D[id] = p;
+}
+
+uintptr_t get_string_ptr(uint8_t id) {
+  //printf("C get_string_ptr(%d): %p\n", id, D[id]);
+  return (uintptr_t)D[id];
+}
+
+// External through functions (mode>0)
+
+void write_char(uint8_t id, uint32_t i, uint8_t v ) {
+  //printf("C write_char(%d, %d): %d\n", id, i, v);
+  D[id][i] = v;
+}
+
+uint8_t read_char(uint8_t id, uint32_t i) {
+  //printf("C read_char(%d, %d): %d\n", id, i, D[id][i]);
+  return D[id][i];
+}
\ No newline at end of file
diff --git a/examples/vhdl/external_buffer/src/tb_ext_byte_vector.vhd b/examples/vhdl/external_buffer/src/tb_ext_byte_vector.vhd
new file mode 100644
index 0000000000..dda5ed7227
--- /dev/null
+++ b/examples/vhdl/external_buffer/src/tb_ext_byte_vector.vhd
@@ -0,0 +1,54 @@
+-- This Source Code Form is subject to the terms of the Mozilla Public
+-- License, v. 2.0. If a copy of the MPL was not distributed with this file,
+-- You can obtain one at http://mozilla.org/MPL/2.0/.
+--
+-- Copyright (c) 2014-2019, Lars Asplund lars.anders.asplund@gmail.com
+
+-- NOTE: This file is expected to be used along with foreign languages (C)
+-- through VHPIDIRECT: https://ghdl.readthedocs.io/en/latest/using/Foreign.html
+-- See main.c for an example of a wrapper application.
+
+--library vunit_lib;
+--context vunit_lib.vunit_context;
+
+library vunit_lib;
+use vunit_lib.run_pkg.all;
+use vunit_lib.logger_pkg.all;
+use vunit_lib.byte_vector_ptr_pkg.all;
+
+entity tb_external_byte_vector is
+  generic ( runner_cfg : string );
+end entity;
+
+architecture tb of tb_external_byte_vector is
+
+  constant block_len : natural := 5;
+
+  constant ebuf: byte_vector_ptr_t := new_byte_vector_ptr( 3*block_len, extfnc);  -- external through VHPIDIRECT functions 'read_char' and 'write_char'
+  constant abuf: byte_vector_ptr_t := new_byte_vector_ptr( 3*block_len, extacc);  -- external through access (requires VHPIDIRECT function 'get_string_ptr')
+
+begin
+
+  main: process
+    variable val, ind: integer;
+  begin
+    test_runner_setup(runner, runner_cfg);
+    info("Init test");
+    for x in 0 to block_len-1 loop
+      val := get(ebuf, x) + 1;
+      ind := block_len+x;
+      set(ebuf, ind, val);
+      info("SET " & to_string(ind) & ": " & to_string(val));
+    end loop;
+    for x in block_len to 2*block_len-1 loop
+      val := get(abuf, x) + 2;
+      ind := block_len+x;
+      set(abuf, ind, val);
+      info("SET " & to_string(ind) & ": " & to_string(val));
+    end loop;
+    info("End test");
+    test_runner_cleanup(runner);
+    wait;
+  end process;
+
+end architecture;
diff --git a/examples/vhdl/external_buffer/src/tb_ext_string.vhd b/examples/vhdl/external_buffer/src/tb_ext_string.vhd
new file mode 100644
index 0000000000..9e1c5f848a
--- /dev/null
+++ b/examples/vhdl/external_buffer/src/tb_ext_string.vhd
@@ -0,0 +1,54 @@
+-- This Source Code Form is subject to the terms of the Mozilla Public
+-- License, v. 2.0. If a copy of the MPL was not distributed with this file,
+-- You can obtain one at http://mozilla.org/MPL/2.0/.
+--
+-- Copyright (c) 2014-2019, Lars Asplund lars.anders.asplund@gmail.com
+
+-- NOTE: This file is expected to be used along with foreign languages (C)
+-- through VHPIDIRECT: https://ghdl.readthedocs.io/en/latest/using/Foreign.html
+-- See main.c for an example of a wrapper application.
+
+--library vunit_lib;
+--context vunit_lib.vunit_context;
+
+library vunit_lib;
+use vunit_lib.run_pkg.all;
+use vunit_lib.logger_pkg.all;
+use vunit_lib.string_ptr_pkg.all;
+
+entity tb_external_string is
+  generic ( runner_cfg : string );
+end entity;
+
+architecture tb of tb_external_string is
+
+  constant block_len : natural := 5;
+
+  constant ebuf: string_ptr_t := new_string_ptr( 3*block_len, extfnc);  -- external through VHPIDIRECT functions 'read_char' and 'write_char'
+  constant abuf: string_ptr_t := new_string_ptr( 3*block_len, extacc);  -- external through access (requires VHPIDIRECT function 'get_string_ptr')
+
+begin
+
+  main: process
+    variable val, ind: integer;
+  begin
+    test_runner_setup(runner, runner_cfg);
+    info("Init test");
+    for x in 1 to block_len loop
+      val := character'pos(get(ebuf, x)) + 1;
+      ind := block_len+x;
+      set(ebuf, ind, character'val(val));
+      info("SET " & to_string(ind) & ": " & to_string(val));
+    end loop;
+    for x in block_len+1 to 2*block_len loop
+      val := character'pos(get(abuf, x)) + 2;
+      ind := block_len+x;
+      set(abuf, ind, character'val(val));
+      info("SET " & to_string(ind) & ": " & to_string(val));
+    end loop;
+    info("End test");
+    test_runner_cleanup(runner);
+    wait;
+  end process;
+
+end architecture;
diff --git a/vunit/test/acceptance/test_external_run_scripts.py b/vunit/test/acceptance/test_external_run_scripts.py
index f2c19911d6..4fcb0f10bf 100644
--- a/vunit/test/acceptance/test_external_run_scripts.py
+++ b/vunit/test/acceptance/test_external_run_scripts.py
@@ -16,7 +16,7 @@
 import sys
 from vunit import ROOT
 from vunit.builtins import VHDL_PATH
-from vunit.test.common import has_simulator, check_report, simulator_is
+from vunit.test.common import has_simulator, check_report, simulator_is, simulator_check
 
 
 def simulator_supports_verilog():
@@ -117,6 +117,13 @@ def test_vhdl_array_axis_vcs_example_project(self):
     def test_vhdl_axi_dma_example_project(self):
         self.check(join(ROOT, "examples", "vhdl", "axi_dma", "run.py"))
 
+    @unittest.skipIf(
+        simulator_check(lambda simclass: not simclass.supports_vhpi()),
+        "This simulator/backend does not support interfacing with external C code"
+    )
+    def test_vhdl_external_buffer_project(self):
+        self.check(join(ROOT, "examples", "vhdl", "external_buffer", "run.py"))
+
     def test_vhdl_user_guide_example_project(self):
         self.check(join(ROOT, "examples", "vhdl", "user_guide", "run.py"), exit_code=1)
         check_report(self.report_file,