diff --git a/CHANGELOG.md b/CHANGELOG.md
index 189b0db501..933dd27fe8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@
 Features:
 ---------
 
+  * [#173](http://github.com/Nelson-numerical-software/nelson/issues/173): convertStringsToChars builtin.
+
 
 
 Bug Fixes:
diff --git a/modules/string/builtin/c/nlsString_builtin.vcxproj b/modules/string/builtin/c/nlsString_builtin.vcxproj
index 94c99dd3bc..77de3f1109 100644
--- a/modules/string/builtin/c/nlsString_builtin.vcxproj
+++ b/modules/string/builtin/c/nlsString_builtin.vcxproj
@@ -170,6 +170,7 @@
   <ItemGroup>
     <ClCompile Include="..\cpp\charBuiltin.cpp" />
     <ClCompile Include="..\cpp\containsBuiltin.cpp" />
+    <ClCompile Include="..\cpp\convertStringsToCharsBuiltin.cpp" />
     <ClCompile Include="..\cpp\countBuiltin.cpp" />
     <ClCompile Include="..\cpp\deblankBuiltin.cpp" />
     <ClCompile Include="..\cpp\endsWithBuiltin.cpp" />
@@ -224,6 +225,7 @@
   <ItemGroup>
     <ClInclude Include="..\include\charBuiltin.hpp" />
     <ClInclude Include="..\include\containsBuiltin.hpp" />
+    <ClInclude Include="..\include\convertStringsToCharsBuiltin.hpp" />
     <ClInclude Include="..\include\countBuiltin.hpp" />
     <ClInclude Include="..\include\deblankBuiltin.hpp" />
     <ClInclude Include="..\include\endsWithBuiltin.hpp" />
diff --git a/modules/string/builtin/c/nlsString_builtin.vcxproj.filters b/modules/string/builtin/c/nlsString_builtin.vcxproj.filters
index 8beb2650c6..d39c972ae5 100644
--- a/modules/string/builtin/c/nlsString_builtin.vcxproj.filters
+++ b/modules/string/builtin/c/nlsString_builtin.vcxproj.filters
@@ -84,6 +84,9 @@
     <ClCompile Include="..\cpp\deblankBuiltin.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\cpp\convertStringsToCharsBuiltin.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <Text Include="..\..\CMakeLists.txt" />
@@ -155,6 +158,9 @@
     <ClInclude Include="..\include\deblankBuiltin.hpp">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="..\include\convertStringsToCharsBuiltin.hpp">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="..\..\loader.nls" />
diff --git a/modules/string/builtin/cpp/Gateway.cpp b/modules/string/builtin/cpp/Gateway.cpp
index 32f4e71613..8db6c7f173 100644
--- a/modules/string/builtin/cpp/Gateway.cpp
+++ b/modules/string/builtin/cpp/Gateway.cpp
@@ -38,6 +38,7 @@
 #include "stringBuiltin.hpp"
 #include "stringsBuiltin.hpp"
 #include "deblankBuiltin.hpp"
+#include "convertStringsToCharsBuiltin.hpp"
 //=============================================================================
 using namespace Nelson;
 //=============================================================================
@@ -68,7 +69,10 @@ static const nlsGateway gateway[] = { { "char", Nelson::StringGateway::charBuilt
     { "deblank", Nelson::StringGateway::deblankBuiltin, 1, 1, CPP_BUILTIN_WITH_EVALUATOR },
     { "strlength", Nelson::StringGateway::strlengthBuiltin, 1, 1, CPP_BUILTIN_WITH_EVALUATOR },
     { "string", Nelson::StringGateway::stringBuiltin, 1, 1, CPP_BUILTIN_WITH_EVALUATOR },
-    { "strings", Nelson::StringGateway::stringsBuiltin, 1, -1, CPP_BUILTIN_WITH_EVALUATOR } };
+    { "strings", Nelson::StringGateway::stringsBuiltin, 1, -1, CPP_BUILTIN_WITH_EVALUATOR },
+    { "convertStringsToChars", Nelson::StringGateway::convertStringsToCharsBuiltin, -1, -1,
+        CPP_BUILTIN_WITH_EVALUATOR },
+};
 //=============================================================================
 NLSGATEWAYFUNC(gateway)
 //=============================================================================
diff --git a/modules/string/builtin/cpp/convertStringsToCharsBuiltin.cpp b/modules/string/builtin/cpp/convertStringsToCharsBuiltin.cpp
new file mode 100644
index 0000000000..d4be40e9c3
--- /dev/null
+++ b/modules/string/builtin/cpp/convertStringsToCharsBuiltin.cpp
@@ -0,0 +1,34 @@
+//=============================================================================
+// Copyright (c) 2016-2019 Allan CORNET (Nelson)
+//=============================================================================
+// LICENCE_BLOCK_BEGIN
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+// LICENCE_BLOCK_END
+//=============================================================================
+#include "ConvertStringsToChars.hpp"
+#include "Error.hpp"
+#include "convertStringsToCharsBuiltin.hpp"
+//=============================================================================
+using namespace Nelson;
+//=============================================================================
+ArrayOfVector
+Nelson::StringGateway::convertStringsToCharsBuiltin(
+    Evaluator* eval, int nLhs, const ArrayOfVector& argIn)
+{
+    if (nLhs > argIn.size()) {
+        Error(_W("Number of Input arguments must the same as output."));
+    }
+    return ConvertStringsToChars(argIn);
+}
+//=============================================================================
\ No newline at end of file
diff --git a/modules/string/builtin/include/convertStringsToCharsBuiltin.hpp b/modules/string/builtin/include/convertStringsToCharsBuiltin.hpp
new file mode 100644
index 0000000000..7e1d479cb0
--- /dev/null
+++ b/modules/string/builtin/include/convertStringsToCharsBuiltin.hpp
@@ -0,0 +1,32 @@
+//=============================================================================
+// Copyright (c) 2016-2019 Allan CORNET (Nelson)
+//=============================================================================
+// LICENCE_BLOCK_BEGIN
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+// LICENCE_BLOCK_END
+//=============================================================================
+#pragma once
+//=============================================================================
+#include "ArrayOf.hpp"
+#include "Evaluator.hpp"
+//=============================================================================
+namespace Nelson {
+//=============================================================================
+	namespace StringGateway {
+    ArrayOfVector
+    convertStringsToCharsBuiltin(Evaluator* eval, int nLhs, const ArrayOfVector& argIn);
+}
+//=============================================================================
+} // namespace Nelson
+//=============================================================================
diff --git a/modules/string/help/en_US/xml/convertStringsToChars.xml b/modules/string/help/en_US/xml/convertStringsToChars.xml
new file mode 100644
index 0000000000..3456d4c805
--- /dev/null
+++ b/modules/string/help/en_US/xml/convertStringsToChars.xml
@@ -0,0 +1,84 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xmldoc>
+	<copyright>SAME AS NELSON SOFTWARE</copyright>
+
+	<language>en_US</language>
+	<keyword>convertStringsToChars</keyword>
+	<short_description>Convert string arrays to character arrays.</short_description>
+
+	<syntax>
+		<syntax_item>C = convertStringsToChars(S)</syntax_item>
+		<syntax_item>[B1, B2, ..., BN] = convertStringsToChars(A1, A2, ..., AN)</syntax_item>
+	</syntax>
+	
+	<param_input>
+		<param_input_item>
+			<param_name>S</param_name>
+			<param_description>if S is a string array, output C will be converted to an cell of strings or an character vector (if S is scalar).</param_description>
+		</param_input_item>
+		<param_input_item>
+			<param_name>A1, A2, ..., AN</param_name>
+			<param_description>variables to convert to char array if it is a string array.</param_description>
+		</param_input_item>
+	</param_input>
+
+	<param_output>
+
+		<param_output_item>
+			<param_name>C</param_name>
+			<param_description>a string array or unaltered variable</param_description>
+		</param_output_item>
+		<param_input_item>
+			<param_name>B1, B2, ..., BN</param_name>
+			<param_description>variables converted to char array if it is a string array.</param_description>
+		</param_input_item>
+
+	</param_output>
+
+	<description>
+		<p><b>convertStringsToChars</b> converts string arrays to character arrays.</p>
+	</description>
+
+
+	<used_function></used_function>
+	<bibliography></bibliography>
+
+<examples>
+
+	<example_item>
+		<example_item_type>nelson</example_item_type>
+		<example_item_description></example_item_description>
+		<example_item_data><![CDATA[A = convertStringsToChars("Nelson")
+A = convertStringsToChars(["Nelson", string(NaN)])]]>
+		</example_item_data>
+	
+	</example_item>
+
+</examples>
+
+	<see_also>
+		<see_also_item>
+			<link linkend="${data_structures}cellstr">cellstr</link>
+		</see_also_item>
+		<see_also_item>
+			<link linkend="${string}string">string</link>
+		</see_also_item>
+		<see_also_item>
+			<link linkend="${string}char">char</link>
+		</see_also_item>
+
+	</see_also>
+
+	<history>
+		<history_item>
+			<history_version>1.0.0</history_version>
+			<history_description>initial version</history_description>
+		</history_item>
+	</history>
+
+	<authors>
+		<author_item>Allan CORNET</author_item>
+	</authors>
+</xmldoc>
+
+
diff --git a/modules/string/src/c/nlsString.vcxproj b/modules/string/src/c/nlsString.vcxproj
index 7a26f0e2a4..598be8aeb7 100644
--- a/modules/string/src/c/nlsString.vcxproj
+++ b/modules/string/src/c/nlsString.vcxproj
@@ -164,6 +164,7 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="..\cpp\ConvertStringsToChars.cpp" />
     <ClCompile Include="..\cpp\IntegerToString.cpp" />
     <ClCompile Include="..\cpp\MatrixToString.cpp" />
     <ClCompile Include="..\cpp\StringCompare.cpp" />
@@ -187,6 +188,7 @@
   <ItemGroup>
     <ClInclude Include="..\..\src\include\nlsString_exports.h" />
     <ClInclude Include="..\..\src\include\ToChar.hpp" />
+    <ClInclude Include="..\include\ConvertStringsToChars.hpp" />
     <ClInclude Include="..\include\IntegerToString.hpp" />
     <ClInclude Include="..\include\MatrixToString.hpp" />
     <ClInclude Include="..\include\StringCompare.hpp" />
diff --git a/modules/string/src/c/nlsString.vcxproj.filters b/modules/string/src/c/nlsString.vcxproj.filters
index 67eeb56c1e..7c36987ee0 100644
--- a/modules/string/src/c/nlsString.vcxproj.filters
+++ b/modules/string/src/c/nlsString.vcxproj.filters
@@ -72,6 +72,9 @@
     <ClCompile Include="..\cpp\StringDeblank.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\cpp\ConvertStringsToChars.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\src\include\ToChar.hpp">
@@ -134,6 +137,9 @@
     <ClInclude Include="..\include\StringDeblank.hpp">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="..\include\ConvertStringsToChars.hpp">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <Text Include="..\..\CMakeLists.txt" />
diff --git a/modules/string/src/cpp/ConvertStringsToChars.cpp b/modules/string/src/cpp/ConvertStringsToChars.cpp
new file mode 100644
index 0000000000..753d5d655f
--- /dev/null
+++ b/modules/string/src/cpp/ConvertStringsToChars.cpp
@@ -0,0 +1,63 @@
+//=============================================================================
+// Copyright (c) 2016-2019 Allan CORNET (Nelson)
+//=============================================================================
+// LICENCE_BLOCK_BEGIN
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+// LICENCE_BLOCK_END
+//=============================================================================
+#include "ConvertStringsToChars.hpp"
+#include "Exception.hpp"
+//=============================================================================
+namespace Nelson {
+ArrayOfVector
+ConvertStringsToChars(const ArrayOfVector& A)
+{
+    ArrayOfVector res;
+    for (auto value : A) {
+        if (value.isStringArray()) {
+            Dimensions dims = value.getDimensions();
+            if (dims.isEmpty(false)) {
+                ArrayOf valueAsCell = ArrayOf(NLS_CELL_ARRAY, dims, nullptr);
+                res.push_back(valueAsCell);
+            } else if (dims.isScalar()) {
+                auto* elementsStr = (ArrayOf*)value.getDataPointer();
+                ArrayOf element = elementsStr[0];
+                if (element.getDataClass() == NLS_CHAR) {
+                    res.push_back(
+                        ArrayOf::characterArrayConstructor(element.getContentAsWideString()));
+                } else {
+                    res.push_back(ArrayOf::characterArrayConstructor(""));
+                }
+            } else {
+                auto* elementsCell = new_with_exception<ArrayOf>(dims.getElementCount(), false);
+                ArrayOf valueAsCell = ArrayOf(NLS_CELL_ARRAY, dims, elementsCell);
+                auto* elementsStr = (ArrayOf*)value.getDataPointer();
+                for (indexType q = 0; q < dims.getElementCount(); q++) {
+                    if (elementsStr[q].getDataClass() == NLS_CHAR) {
+                        elementsCell[q] = elementsStr[q];
+                    } else {
+                        elementsCell[q] = ArrayOf::characterArrayConstructor("");
+                    }
+                }
+                res.push_back(valueAsCell);
+            }
+        } else {
+            res.push_back(value);
+        }
+	}
+    return res;
+}
+//=============================================================================
+}  // namespace Nelson
+//=============================================================================
diff --git a/modules/string/src/cpp/StringCompare.cpp b/modules/string/src/cpp/StringCompare.cpp
index d7c2546fda..f7d2003de2 100644
--- a/modules/string/src/cpp/StringCompare.cpp
+++ b/modules/string/src/cpp/StringCompare.cpp
@@ -43,7 +43,7 @@ compareString(std::wstring A, std::wstring B, bool bCaseSensitive, indexType len
         return compareString(strA, strB, false);
     }
     if (bCaseSensitive) {
-        bEq = (A.compare(B) == 0);
+        bEq = (A == B);
     } else {
         bEq = boost::iequals(A, B);
     }
@@ -99,8 +99,8 @@ StringCompare(ArrayOf A, ArrayOf B, bool bCaseSensitive, indexType len)
                 ArrayOf elementA = cellA[k];
                 ArrayOf elementB = cellB[k];
                 if (elementA.isRowVectorCharacterArray() && elementB.isRowVectorCharacterArray()) {
-                    Cp[k] = compareString(elementA.getContentAsWideString(),
-                        elementB.getContentAsWideString(), bCaseSensitive, len);
+                    Cp[k] = static_cast<Nelson::logical>(compareString(elementA.getContentAsWideString(),
+                        elementB.getContentAsWideString(), bCaseSensitive, len));
                 } else if (elementA.isCharacterArray() && elementB.isCharacterArray()) {
                     wstringVector s1 = elementA.getContentAsWideStringVector();
                     wstringVector s2 = elementB.getContentAsWideStringVector();
@@ -201,8 +201,8 @@ StringCompare(ArrayOf A, ArrayOf B, bool bCaseSensitive, indexType len)
             } else {
                 ArrayOf elementA = cellA[k];
                 if (elementA.isCharacterArray() && scalar2.isCharacterArray()) {
-                    Cp[k] = compareString(elementA.getContentAsWideString(),
-                        scalar2.getContentAsWideString(), bCaseSensitive, len);
+                    Cp[k] = static_cast<Nelson::logical>(compareString(elementA.getContentAsWideString(),
+                        scalar2.getContentAsWideString(), bCaseSensitive, len));
                 } else {
                     Cp[k] = false;
                 }
diff --git a/modules/string/src/cpp/StringContains.cpp b/modules/string/src/cpp/StringContains.cpp
index 7f207dd5d3..565f15e784 100644
--- a/modules/string/src/cpp/StringContains.cpp
+++ b/modules/string/src/cpp/StringContains.cpp
@@ -68,7 +68,7 @@ StringContains(ArrayOf A, ArrayOf Pattern, bool bCaseSensitive)
             auto* cellA = (ArrayOf*)(A.getDataPointer());
             for (size_t k = 0; k < nbA; k++) {
                 result[k]
-                    = containsString(cellA[k].getContentAsWideString(), pattern, bCaseSensitive);
+                    = static_cast<Nelson::logical>(containsString(cellA[k].getContentAsWideString(), pattern, bCaseSensitive));
             }
             res = ArrayOf(NLS_LOGICAL, dimA, result);
         } else if ((A.isStringArray() || IsCellOfString(A))
@@ -85,7 +85,7 @@ StringContains(ArrayOf A, ArrayOf Pattern, bool bCaseSensitive)
                     bool val = containsString(cellA[k].getContentAsWideString(),
                         cellPattern[l].getContentAsWideString(), bCaseSensitive);
                     if (val) {
-                        result[k] = val;
+                        result[k] = static_cast<Nelson::logical>(val);
                         break;
                     }
                 }
diff --git a/modules/string/src/cpp/StringEndsWith.cpp b/modules/string/src/cpp/StringEndsWith.cpp
index 1a137a207f..429e0302ac 100644
--- a/modules/string/src/cpp/StringEndsWith.cpp
+++ b/modules/string/src/cpp/StringEndsWith.cpp
@@ -69,7 +69,7 @@ StringEndsWith(ArrayOf A, ArrayOf Pattern, bool bCaseSensitive)
             auto* cellA = (ArrayOf*)(A.getDataPointer());
             for (size_t k = 0; k < nbA; k++) {
                 result[k]
-                    = endsWithString(cellA[k].getContentAsWideString(), pattern, bCaseSensitive);
+                    = static_cast<Nelson::logical>(endsWithString(cellA[k].getContentAsWideString(), pattern, bCaseSensitive));
             }
             res = ArrayOf(NLS_LOGICAL, dimA, result);
         } else if ((A.isStringArray() || IsCellOfString(A))
@@ -86,7 +86,7 @@ StringEndsWith(ArrayOf A, ArrayOf Pattern, bool bCaseSensitive)
                     bool val = endsWithString(cellA[k].getContentAsWideString(),
                         cellPattern[l].getContentAsWideString(), bCaseSensitive);
                     if (val) {
-                        result[k] = val;
+                        result[k] = static_cast<Nelson::logical>(val);
                         break;
                     }
                 }
diff --git a/modules/string/src/cpp/StringStartsWith.cpp b/modules/string/src/cpp/StringStartsWith.cpp
index c099aaf5fc..8364c8177a 100644
--- a/modules/string/src/cpp/StringStartsWith.cpp
+++ b/modules/string/src/cpp/StringStartsWith.cpp
@@ -69,7 +69,7 @@ StringStartsWith(ArrayOf A, ArrayOf Pattern, bool bCaseSensitive)
             auto* cellA = (ArrayOf*)(A.getDataPointer());
             for (size_t k = 0; k < nbA; k++) {
                 result[k]
-                    = startsWithString(cellA[k].getContentAsWideString(), pattern, bCaseSensitive);
+                    = static_cast<Nelson::logical>(startsWithString(cellA[k].getContentAsWideString(), pattern, bCaseSensitive));
             }
             res = ArrayOf(NLS_LOGICAL, dimA, result);
         } else if ((A.isStringArray() || IsCellOfString(A))
@@ -86,7 +86,7 @@ StringStartsWith(ArrayOf A, ArrayOf Pattern, bool bCaseSensitive)
                     bool val = startsWithString(cellA[k].getContentAsWideString(),
                         cellPattern[l].getContentAsWideString(), bCaseSensitive);
                     if (val) {
-                        result[k] = val;
+                        result[k] = static_cast<Nelson::logical>(val);
                         break;
                     }
                 }
diff --git a/modules/string/src/cpp/StringToDouble.cpp b/modules/string/src/cpp/StringToDouble.cpp
index a2dc16a16c..4d145914c1 100644
--- a/modules/string/src/cpp/StringToDouble.cpp
+++ b/modules/string/src/cpp/StringToDouble.cpp
@@ -57,15 +57,15 @@ stringToDouble(const std::wstring& str, bool& wasConverted)
         wasConverted = true;
     } else {
         std::wstring STR = ToUpper(str);
-        if (STR.compare(ToUpper(NanString)) == 0 || STR.compare(ToUpper(NegNanString)) == 0
-            || STR.compare(ToUpper(PosNanString)) == 0) {
+        if (STR == ToUpper(NanString) || STR == ToUpper(NegNanString)
+            || STR == ToUpper(PosNanString)) {
             res = nan("");
             wasConverted = true;
-        } else if (STR.compare(ToUpper(NegInfString)) == 0) {
+        } else if (STR == ToUpper(NegInfString)) {
             res = returnInfinity(false);
             wasConverted = true;
-        } else if (STR.compare(ToUpper(InfString)) == 0
-            || STR.compare(ToUpper(PosInfString)) == 0) {
+        } else if (STR == ToUpper(InfString)
+            || STR == ToUpper(PosInfString)) {
             res = returnInfinity(true);
             wasConverted = true;
         } else {
diff --git a/modules/string/src/include/ConvertStringsToChars.hpp b/modules/string/src/include/ConvertStringsToChars.hpp
new file mode 100644
index 0000000000..a9f4d61cca
--- /dev/null
+++ b/modules/string/src/include/ConvertStringsToChars.hpp
@@ -0,0 +1,30 @@
+//=============================================================================
+// Copyright (c) 2016-2019 Allan CORNET (Nelson)
+//=============================================================================
+// LICENCE_BLOCK_BEGIN
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+// LICENCE_BLOCK_END
+//=============================================================================
+#pragma once
+//=============================================================================
+#include "ArrayOf.hpp"
+#include "nlsString_exports.h"
+//=============================================================================
+namespace Nelson {
+//=============================================================================
+NLSSTRING_IMPEXP ArrayOfVector
+ConvertStringsToChars(const ArrayOfVector &A);
+//=============================================================================
+}
+//=============================================================================
diff --git a/modules/string/tests/test_convertStringsToChars.nls b/modules/string/tests/test_convertStringsToChars.nls
new file mode 100644
index 0000000000..e494d6d9f7
--- /dev/null
+++ b/modules/string/tests/test_convertStringsToChars.nls
@@ -0,0 +1,42 @@
+//=============================================================================
+// Copyright (c) 2016-2019 Allan CORNET (Nelson)
+//=============================================================================
+// LICENCE_BLOCK_BEGIN
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 2 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+// LICENCE_BLOCK_END
+//=============================================================================
+assert_isequal(nargin('convertStringsToChars'), -1);
+assert_isequal(nargout('convertStringsToChars'), -1);
+//=============================================================================
+[A, B, C, D] = convertStringsToChars('one', 2, "three", ["four" ; "five"]);
+assert_isequal(A, 'one');
+assert_isequal(B, 2);
+assert_isequal(C, 'three');
+assert_isequal(D, {'four'; 'five'});
+//=============================================================================
+[A, B, C, D] = convertStringsToChars('one', 2, "three", ["four" ; string(NaN) ; "five"]);
+assert_isequal(A, 'one');
+assert_isequal(B, 2);
+assert_isequal(C, 'three');
+assert_isequal(D, {'four'; ''; 'five'});
+//=============================================================================
+[A, B, C, D] = convertStringsToChars('one', 2, string(NaN), ["four" ; string(NaN) ; "five"]);
+assert_isequal(A, 'one');
+assert_isequal(B, 2);
+assert_isequal(C, '');
+assert_isequal(D, {'four'; ''; 'five'});
+//=============================================================================
+R = convertStringsToChars(string([]));
+assert_isequal(R, {});
+//=============================================================================