diff --git a/backend/codablock.c b/backend/codablock.c
index 465eba14..2a565d60 100644
--- a/backend/codablock.c
+++ b/backend/codablock.c
@@ -115,7 +115,7 @@ int GetPossibleCharacterSet(unsigned char C)
  *  int CFollowing  The number of characters encodable in CodeC if we
  *          start here.
  */
-void CreateCharacterSetTable(CharacterSetTable T[], unsigned char *data, int dataLength)
+static void CreateCharacterSetTable(CharacterSetTable T[], unsigned char *data,const size_t dataLength)
 {
     int charCur;
     int runChar;
@@ -205,7 +205,7 @@ int RemainingDigits(CharacterSetTable *T, int charCur,int emptyColumns)
  *  Return value    Resulting row count
  */
 
-int Columns2Rows(CharacterSetTable *T, unsigned char *data, int dataLength,
+static int Columns2Rows(CharacterSetTable *T, unsigned char *data, const size_t dataLength,
         int * pRows, int * pUseColumns, int * pSet, int * pFillings)
 {
     int useColumns;     /* Usable Characters per line */
@@ -430,7 +430,7 @@ int Columns2Rows(CharacterSetTable *T, unsigned char *data, int dataLength,
 }
 /* Find columns if row count is given.
  */
-int Rows2Columns(CharacterSetTable *T, unsigned char *data, int dataLength,
+static int Rows2Columns(CharacterSetTable *T, unsigned char *data, const size_t dataLength,
         int * pRows, int * pUseColumns, int * pSet, int * pFillings)
 {
     int errorCur;
@@ -630,8 +630,7 @@ void SumASCII(uchar **ppOutPos, int Sum, int CharacterSet)
 /* Main function called by zint framework
  */
 int codablock(struct zint_symbol *symbol,const unsigned char source[], const size_t length) {
-    int charCur;
-    int dataLength;
+    size_t charCur,dataLength;
     int Error;
     int rows, columns, useColumns;
     int fillings;
@@ -733,7 +732,7 @@ int codablock(struct zint_symbol *symbol,const unsigned char source[], const siz
     Sum1=Sum2=0;
     if (rows>1)
     {
-        int charCur;
+        size_t charCur;
         for (charCur=0 ; charCur<dataLength ; charCur++) {
             Sum1=(Sum1 + (charCur%86+1)*data[charCur])%86;
             Sum2=(Sum2 + (charCur%86)*data[charCur])%86;
diff --git a/backend/common.c b/backend/common.c
index 389ae366..5c62e94c 100644
--- a/backend/common.c
+++ b/backend/common.c
@@ -59,7 +59,7 @@ char itoc(const int source) {
 void bin_append(const int arg, const int length, char *binary) {
     int i;
     int start;
-    int posn = strlen(binary);
+    size_t posn = strlen(binary);
     
     start = 0x01 << (length - 1);
     
@@ -228,7 +228,7 @@ int is_extendable(const int symbology) {
     return 0;
 }
 
-int istwodigits(const unsigned char source[], const int position) {
+int istwodigits(const unsigned char source[], const size_t position) {
     if ((source[position] >= '0') && (source[position] <= '9')) {
         if ((source[position + 1] >= '0') && (source[position + 1] <= '9')) {
             return 1;
diff --git a/backend/common.h b/backend/common.h
index 9053f3d4..73b87218 100644
--- a/backend/common.h
+++ b/backend/common.h
@@ -64,7 +64,7 @@ extern "C" {
     extern int posn(const char set_string[], const char data);
     extern int module_is_set(const struct zint_symbol *symbol, const int y_coord, const int x_coord);
     extern void set_module(struct zint_symbol *symbol, const int y_coord, const int x_coord);
-    extern int istwodigits(const unsigned char source[], const int position);
+    extern int istwodigits(const unsigned char source[], const size_t position);
     extern int parunmodd(const unsigned char llyth);
     extern void expand(struct zint_symbol *symbol, const char data[]);
     extern void unset_module(struct zint_symbol *symbol, const int y_coord, const int x_coord);
diff --git a/backend/composite.c b/backend/composite.c
index 3d174b5c..d69427a6 100644
--- a/backend/composite.c
+++ b/backend/composite.c
@@ -150,7 +150,7 @@ static int cc_a(struct zint_symbol *symbol, char source[], int cc_width) {
         codeWords[i] = 0;
     }
 
-    bitlen = strlen(source);
+	bitlen = (int)strlen(source);
 
     for (i = 0; i < 208; i++) {
         local_source[i] = '0';
diff --git a/backend/dmatrix.c b/backend/dmatrix.c
index 4c009668..78df9398 100644
--- a/backend/dmatrix.c
+++ b/backend/dmatrix.c
@@ -256,7 +256,7 @@ static void dminsert(char binary_string[], const int posn, const char newbit) {
     binary_string[posn] = newbit;
 }
 
-static void insert_value(unsigned char binary_stream[], const int posn, const size_t streamlen, const int newbit) {
+static void insert_value(unsigned char binary_stream[], const int posn, const int streamlen, const int newbit) {
     int i;
 
     for(i = (int)streamlen; i > posn; i--) {
@@ -265,15 +265,15 @@ static void insert_value(unsigned char binary_stream[], const int posn, const si
     binary_stream[posn] = (unsigned char) newbit;
 }
 
-static int p_r_6_2_1(const unsigned char inputData[], const int position, const size_t sourcelen) {
+static int p_r_6_2_1(const unsigned char inputData[], const size_t position, const size_t sourcelen) {
     /* Annex P section (r)(6)(ii)(I)
        "If one of the three X12 terminator/separator characters first
         occurs in the yet to be processed data before a non-X12 character..."
      */
 
     size_t i;
-    int nonX12Position = 0;
-    int specialX12Position = 0;
+    size_t nonX12Position = 0;
+    size_t specialX12Position = 0;
     int retval = 0;
 
     for (i = position; i < sourcelen; i++) {
diff --git a/backend/dotcode.c b/backend/dotcode.c
index 0175d6a7..c0fb7681 100644
--- a/backend/dotcode.c
+++ b/backend/dotcode.c
@@ -1203,13 +1203,15 @@ int dotcode(struct zint_symbol *symbol, const unsigned char source[], int length
     int binary_finish = 0;
     int debug = 0;
     int padding_dots, is_first;
+#ifdef _MSC_VER
+    unsigned char* masked_codeword_array;
+#endif
 
 #ifndef _MSC_VER
     unsigned char codeword_array[length * 3];
 #else
     char* dot_stream;
     char* dot_array;
-    unsigned char* masked_codeword_array;
     unsigned char* codeword_array = (unsigned char *) _alloca(length * 3 * sizeof (unsigned char));
 #endif /* _MSC_VER */
     
diff --git a/backend/eci.c b/backend/eci.c
index 495273cc..4545613d 100644
--- a/backend/eci.c
+++ b/backend/eci.c
@@ -39,7 +39,7 @@
 #endif
 
 /* Convert Unicode to other character encodings */
-int utf_to_eci(int eci, const unsigned char source[], unsigned char dest[], int *length) {
+int utf_to_eci(const int eci, const unsigned char source[], unsigned char dest[], size_t *length) {
     int glyph;
     int bytelen;
     int in_posn;
@@ -288,7 +288,7 @@ int utf_to_eci(int eci, const unsigned char source[], unsigned char dest[], int
 }
 
 /* Find the lowest ECI mode which will encode a given set of Unicode text */
-int get_best_eci(unsigned char source[], int length) {
+int get_best_eci(unsigned char source[], size_t length) {
     int eci = 3;
 
 #ifndef _MSC_VER
diff --git a/backend/hanxin.c b/backend/hanxin.c
index 000f9b35..9585facd 100644
--- a/backend/hanxin.c
+++ b/backend/hanxin.c
@@ -65,7 +65,7 @@ int getsubmode(char input) {
 
 /* Calculate the approximate length of the binary string */
 static int calculate_binlength(char mode[], int source[], const size_t length, int eci) {
-    int i;
+    size_t i;
     char lastmode = 't';
     int est_binlen = 0;
     int submode = 1;
@@ -226,7 +226,7 @@ int isFourByte(int glyph, int glyph2) {
 
 /* Calculate mode switching */
 static void hx_define_mode(char mode[], int source[], const size_t length) {
-    int i;
+    size_t i;
     char lastmode = 't';
     int done;
     
diff --git a/backend/large.c b/backend/large.c
index d7fe2082..a0bdc5c2 100644
--- a/backend/large.c
+++ b/backend/large.c
@@ -172,7 +172,8 @@ short int islarger(short int accum[], short int reg[]) {
 }
 
 void binary_load(short int reg[], char data[], const size_t src_len) {
-    int read, i;
+	size_t    read;
+	int       i;
     short int temp[112] = {0};
 
     for (i = 0; i < 112; i++) {
diff --git a/backend/library.c b/backend/library.c
index a084beae..00c973ea 100644
--- a/backend/library.c
+++ b/backend/library.c
@@ -145,8 +145,9 @@ void ZBarcode_Delete(struct zint_symbol *symbol) {
     free(symbol);
 }
 
-extern int get_best_eci(unsigned char source[], int length); /* Calculate suitable ECI mode */
-extern int utf_to_eci(int eci, const unsigned char source[], unsigned char dest[], int *length); /* Convert Unicode to other encodings */
+extern int get_best_eci(unsigned char source[], size_t length); /* Calculate suitable ECI mode */
+extern int utf_to_eci(const int eci, const unsigned char source[], unsigned char dest[], size_t *length); /* Convert Unicode to other encodings */
+
 
 extern int eanx(struct zint_symbol *symbol, unsigned char source[], int length); /* EAN system barcodes */
 extern int c39(struct zint_symbol *symbol, unsigned char source[], const size_t length); /* Code 3 from 9 (or Code 39) */
@@ -203,7 +204,7 @@ extern int grid_matrix(struct zint_symbol *symbol, const unsigned char source[],
 extern int han_xin(struct zint_symbol * symbol, const unsigned char source[], size_t length); /* Han Xin */
 extern int dotcode(struct zint_symbol * symbol, const unsigned char source[], int length); /* DotCode */
 extern int codablock(struct zint_symbol * symbol, const unsigned char source[], const size_t length); /* Codablock */
-extern int upnqr(struct zint_symbol *symbol, const unsigned char source[], int length); /* UPNQR */
+extern int upnqr(struct zint_symbol *symbol, const unsigned char source[], size_t length); /* UPNQR */
 extern int qr_code(struct zint_symbol *symbol, const unsigned char source[], size_t length); /* Data Matrix (IEC16022) */
 extern int dmatrix(struct zint_symbol *symbol, const unsigned char source[], const size_t in_length); /* QR Code */
 
@@ -615,7 +616,7 @@ static int extended_charset(struct zint_symbol *symbol, const unsigned char *sou
     return error_number;
 }
 
-static int reduced_charset(struct zint_symbol *symbol, const unsigned char *source, int in_length) {
+static int reduced_charset(struct zint_symbol *symbol, const unsigned char *source, size_t in_length) {
     /* These are the "norm" standards which only support Latin-1 at most */
     int error_number = 0;
 
@@ -1049,7 +1050,7 @@ int ZBarcode_Encode(struct zint_symbol *symbol, const unsigned char *source,int
             case BARCODE_MICROQR:
             case BARCODE_GRIDMATRIX:
             case BARCODE_HANXIN:
-                error_number = utf_to_eci(symbol->eci, source, local_source, &in_length);
+                error_number = utf_to_eci(symbol->eci, source, local_source, (size_t*)&in_length);
                 error_number = extended_charset(symbol, local_source, in_length);
                 break;
             default:
@@ -1310,4 +1311,4 @@ int ZBarcode_Render(struct zint_symbol *symbol, const float width, const float h
 
 int ZBarcode_Version() {
     return (ZINT_VERSION_MAJOR * 10000) + (ZINT_VERSION_MINOR * 100) + ZINT_VERSION_RELEASE;
-}
\ No newline at end of file
+}
diff --git a/backend/qr.c b/backend/qr.c
index 09aad516..cf0364a0 100644
--- a/backend/qr.c
+++ b/backend/qr.c
@@ -42,7 +42,7 @@
 #include <stdlib.h>     /* abs */
 #include <assert.h>
 
-extern int utf_to_eci(int eci, const unsigned char source[], unsigned char dest[], int *length); /* Convert Unicode to other encodings */
+extern int utf_to_eci(const int eci, const unsigned char source[], unsigned char dest[], size_t *length); /* Convert Unicode to other encodings */
 
 /* Returns true if input glyph is in the Alphanumeric set */
 static int in_alpha(const int glyph) {
@@ -147,7 +147,7 @@ static int tribus(const int version,const int a,const int b,const int c) {
 }
 
 /* Convert input data to a binary stream and add padding */
-static void qr_binary(int datastream[], const int version, const int target_binlen, const char mode[], const int jisdata[], const size_t length, const int gs1, const int eci, const int est_binlen, int debug) {
+static void qr_binary(int datastream[], const int version, const int target_binlen, const char mode[], const int jisdata[], const size_t length, const int gs1, const int eci, const int est_binlen,const int debug) {
     int position = 0;
     int short_data_block_length, i;
     char data_block, padbits;
@@ -1313,7 +1313,7 @@ static void applyOptimisation(const int version,char inputMode[], const size_t i
     free(blockMode);
 }
 
-static int blockLength(const int start,const char inputMode[],const size_t inputLength) {
+static int blockLength(const size_t start,const char inputMode[],const size_t inputLength) {
     /* Find the length of the block starting from 'start' */
     size_t i;
     int    count;
@@ -1648,7 +1648,7 @@ int qr_code(struct zint_symbol *symbol, const unsigned char source[], size_t len
 
 /* NOTE: From this point forward concerns Micro QR Code only */
 
-static int micro_qr_intermediate(char binary[], const int jisdata[], const char mode[], const size_t length, int *kanji_used, int *alphanum_used, int *byte_used, int debug) {
+static int micro_qr_intermediate(char binary[], const int jisdata[], const char mode[], const size_t length, int *kanji_used, int *alphanum_used, int *byte_used,const int debug) {
     /* Convert input data to an "intermediate stage" where data is binary encoded but
        control information is not */
     int position = 0;
@@ -2888,7 +2888,7 @@ int microqr(struct zint_symbol *symbol, const unsigned char source[], size_t len
 }
 
 /* For UPNQR the symbol size and error correction capacity is fixed */
-int upnqr(struct zint_symbol *symbol, const unsigned char source[], int length) {
+int upnqr(struct zint_symbol *symbol, const unsigned char source[], size_t length) {
     int i, j, est_binlen;
     int ecc_level, version, target_binlen, blocks, size;
     int bitmask, error_number;
diff --git a/backend/qr.h b/backend/qr.h
index f2790e16..d1c248f5 100644
--- a/backend/qr.h
+++ b/backend/qr.h
@@ -164,4 +164,4 @@ static const unsigned int qr_annex_c1[] = {
     0x4445, 0x4172, 0x4e2b, 0x4b1c, 0x55ae, 0x5099, 0x5fc0, 0x5af7, 0x6793, 0x62a4, 0x6dfd, 0x68ca, 0x7678, 0x734f,
     0x7c16, 0x7921, 0x06de, 0x03e9, 0x0cb0, 0x0987, 0x1735, 0x1202, 0x1d5b, 0x186c, 0x2508, 0x203f, 0x2f66, 0x2a51, 0x34e3,
     0x31d4, 0x3e8d, 0x3bba
-};
\ No newline at end of file
+};
diff --git a/win32/libzint.vcxproj b/win32/libzint.vcxproj
index afa2ee2c..c3436c36 100644
--- a/win32/libzint.vcxproj
+++ b/win32/libzint.vcxproj
@@ -135,7 +135,7 @@
       <LinkLibraryDependencies>false</LinkLibraryDependencies>
     </ProjectReference>
     <Link>
-      <AdditionalDependencies>libpng16d.lib;zlibd.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>%(AdditionalDependencies)</AdditionalDependencies>
       <OutputFile>$(OutDir)zintd.dll</OutputFile>
       <AdditionalLibraryDirectories>..\extern\libpng\lib\x86;..\extern\zlib\lib\x86;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
       <IgnoreSpecificDefaultLibraries>libcmtd.lib;%(IgnoreSpecificDefaultLibraries)</IgnoreSpecificDefaultLibraries>
@@ -169,7 +169,7 @@
       <LinkLibraryDependencies>false</LinkLibraryDependencies>
     </ProjectReference>
     <Link>
-      <AdditionalDependencies>libpng16d.lib;zlibd.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>zlibd.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <OutputFile>$(OutDir)zintd.dll</OutputFile>
       <AdditionalLibraryDirectories>..\extern\libpng\lib\x64;..\extern\zlib\lib\x64;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
       <IgnoreSpecificDefaultLibraries>libcmtd.lib;%(IgnoreSpecificDefaultLibraries)</IgnoreSpecificDefaultLibraries>