diff --git a/CMakeLists.txt b/CMakeLists.txt
index 80656e15..ece02309 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -72,6 +72,10 @@ if(NOT MSVC) # Use default warnings if MSVC otherwise inundated
     if(C_COMPILER_FLAG_WSHADOW)
         add_compile_options("-Wshadow")
     endif()
+    check_c_compiler_flag("-Wshorten-64-to-32" C_COMPILER_FLAG_WSHORTEN64TO32)
+    if(C_COMPILER_FLAG_WSHORTEN64TO32)
+        add_compile_options("-Wshorten-64-to-32")
+    endif()
     check_c_compiler_flag("-Wundef" C_COMPILER_FLAG_WUNDEF)
     if(C_COMPILER_FLAG_WUNDEF)
         add_compile_options("-Wundef")
diff --git a/backend/2of5.c b/backend/2of5.c
index aafee388..dd629c2c 100644
--- a/backend/2of5.c
+++ b/backend/2of5.c
@@ -1,7 +1,7 @@
 /* 2of5.c - Handles non-interleaved Code 2 of 5 barcodes */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -103,7 +103,7 @@ static int c25_common(struct zint_symbol *symbol, const unsigned char source[],
     memcpy(d, start_stop[1], start_length - 1);
     d += start_length - 1;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     /* Exclude check digit from HRT if hidden */
     z_hrt_cpy_nochk(symbol, local_source, length - (symbol->option_2 == 2));
diff --git a/backend/2of5inter.c b/backend/2of5inter.c
index 83d27105..7873197c 100644
--- a/backend/2of5inter.c
+++ b/backend/2of5inter.c
@@ -1,7 +1,7 @@
 /* 2of5inter.c - Handles Code 2 of 5 Interleaved */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -96,7 +96,7 @@ INTERNAL int zint_c25_inter_common(struct zint_symbol *symbol, unsigned char sou
     memcpy(d, "311", 3);
     d += 3;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     if (!dont_set_height) {
         if (symbol->output_options & COMPLIANT_HEIGHT) {
diff --git a/backend/auspost.c b/backend/auspost.c
index 8f6b2f15..2d2b562d 100644
--- a/backend/auspost.c
+++ b/backend/auspost.c
@@ -1,7 +1,7 @@
 /* auspost.c - Handles Australia Post 4-State Barcode */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -76,7 +76,7 @@ static unsigned char aus_convert_pattern(const char data, const int shift) {
 
 /* Adds Reed-Solomon error correction to auspost */
 static char *aus_rs_error(const char data_pattern[], char *d) {
-    const int length = d - data_pattern;
+    const int length = (int) (d - data_pattern);
     int reader, triple_writer;
     unsigned char triple[31];
     unsigned char result[5];
@@ -228,7 +228,7 @@ INTERNAL int zint_auspost(struct zint_symbol *symbol, unsigned char source[], in
     }
 
     /* Filler bar */
-    h = d - data_pattern;
+    h = (int) (d - data_pattern);
     switch (h) {
         case 22:
         case 37:
@@ -248,7 +248,7 @@ INTERNAL int zint_auspost(struct zint_symbol *symbol, unsigned char source[], in
 
     /* Turn the symbol into a bar pattern ready for plotting */
     writer = 0;
-    h = d - data_pattern;
+    h = (int) (d - data_pattern);
     for (loopey = 0; loopey < h; loopey++) {
         if (data_pattern[loopey] == '1' || data_pattern[loopey] == '0') {
             z_set_module(symbol, 0, writer);
diff --git a/backend/bc412.c b/backend/bc412.c
index 79074989..1e3c8e36 100644
--- a/backend/bc412.c
+++ b/backend/bc412.c
@@ -1,7 +1,7 @@
 /* bc412.c - Handles IBM BC412 (SEMI T1-95) symbology */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2022-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2022-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -130,7 +130,7 @@ INTERNAL int zint_bc412(struct zint_symbol *symbol, unsigned char source[], int
     memcpy(d, "111", 3);
     d += 3;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     if (symbol->output_options & COMPLIANT_HEIGHT) {
         /* SEMI T1-95 Table 1 "Module" (Character) Height 2mm ± 0.025mm, using Module Spacing 0.12mm ± 0.025mm as
diff --git a/backend/channel.c b/backend/channel.c
index 785ab191..82e834da 100644
--- a/backend/channel.c
+++ b/backend/channel.c
@@ -240,7 +240,7 @@ INTERNAL int zint_channel(struct zint_symbol *symbol, unsigned char source[], in
         *d++ = z_itoc(B[i]);
     }
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     if (symbol->output_options & COMPLIANT_HEIGHT) {
         /* ANSI/AIM BC12-1998 gives min height as 5mm or 15% of length; X left as application specification so use
diff --git a/backend/codabar.c b/backend/codabar.c
index 4ba1e6e2..f9736009 100644
--- a/backend/codabar.c
+++ b/backend/codabar.c
@@ -1,7 +1,7 @@
 /* codabar.c - Handles Codabar */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -115,7 +115,7 @@ INTERNAL int zint_codabar(struct zint_symbol *symbol, unsigned char source[], in
         }
     }
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     if (symbol->output_options & COMPLIANT_HEIGHT) {
         /* BS EN 798:1995 4.4.1 (d) max of 5mm / 0.43mm (X max) ~ 11.628 or 15% of width where (taking N =
diff --git a/backend/codablock.c b/backend/codablock.c
index 7abcdcd7..543310e7 100644
--- a/backend/codablock.c
+++ b/backend/codablock.c
@@ -1,7 +1,7 @@
 /* codablock.c - Handles Codablock-F */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2016-2025 Harald Oehlmann
+    Copyright (C) 2016-2026 Harald Oehlmann
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -861,7 +861,7 @@ INTERNAL int zint_codablockf(struct zint_symbol *symbol, unsigned char source[],
         }
         memcpy(d, "2331112", 7); /* Stop character (106, not in `zint_C128Table[]`) */
         d += 7;
-        z_expand(symbol, dest, d - dest);
+        z_expand(symbol, dest, (int) (d - dest));
     }
 
     if (symbol->output_options & COMPLIANT_HEIGHT) {
diff --git a/backend/code.c b/backend/code.c
index cb5cc5d7..af46fff3 100644
--- a/backend/code.c
+++ b/backend/code.c
@@ -1,7 +1,7 @@
 /* code.c - Handles Code 39, 39+, 93 and VIN */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -174,7 +174,7 @@ INTERNAL int zint_code39(struct zint_symbol *symbol, unsigned char source[], int
 
     if (symbol->symbology == BARCODE_LOGMARS || symbol->symbology == BARCODE_HIBC_39) {
         /* LOGMARS and HIBC use wider 'wide' bars than normal Code 39 */
-        counter = d - dest;
+        counter = (int) (d - dest);
         for (i = 0; i < counter; i++) {
             if (dest[i] == '2') {
                 dest[i] = '3';
@@ -186,7 +186,7 @@ INTERNAL int zint_code39(struct zint_symbol *symbol, unsigned char source[], int
         printf("Barspaces: %.*s\n", (int) (d - dest), dest);
     }
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     if (symbol->output_options & COMPLIANT_HEIGHT) {
         if (symbol->symbology == BARCODE_LOGMARS) {
@@ -261,7 +261,7 @@ INTERNAL int zint_excode39(struct zint_symbol *symbol, unsigned char source[], i
         memcpy(b, EC39Ctrl[source[i]], 2);
         b += EC39Ctrl[source[i]][1] ? 2 : 1;
     }
-    if (b - buffer > 86) {
+    if ((int) (b - buffer) > 86) {
         return z_errtxtf(ZINT_ERROR_TOO_LONG, symbol, 317,
                         "Input too long, requires %d symbol characters (maximum 86)", (int) (b - buffer));
     }
@@ -275,7 +275,7 @@ INTERNAL int zint_excode39(struct zint_symbol *symbol, unsigned char source[], i
     }
 
     /* Then send the buffer to the C39 function */
-    if ((error_number = zint_code39(symbol, buffer, b - buffer)) >= ZINT_ERROR) {
+    if ((error_number = zint_code39(symbol, buffer, (int) (b - buffer))) >= ZINT_ERROR) {
         return error_number;
     }
 
@@ -341,7 +341,7 @@ INTERNAL int zint_code93(struct zint_symbol *symbol, unsigned char source[], int
     }
 
     /* Now we can check the true length of the barcode */
-    h = b - buffer;
+    h = (int) (b - buffer);
     if (h > 123) {
         return z_errtxtf(ZINT_ERROR_TOO_LONG, symbol, 332,
                         "Input too long, requires %d symbol characters (maximum 123)", h);
@@ -394,7 +394,7 @@ INTERNAL int zint_code93(struct zint_symbol *symbol, unsigned char source[], int
     memcpy(d, "1111411", 7);
     d += 7;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     if (symbol->output_options & COMPLIANT_HEIGHT) {
         /* ANSI/AIM BC5-1995 Section 2.6 minimum height 0.2" or 15% of symbol length, whichever is greater
@@ -504,7 +504,7 @@ INTERNAL int zint_vin(struct zint_symbol *symbol, unsigned char source[], int le
     memcpy(d, C39Table[43], 9);
     d += 9;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     z_hrt_cpy_nochk(symbol, source, length);
 
diff --git a/backend/code11.c b/backend/code11.c
index 7bd2ad62..c308b04b 100644
--- a/backend/code11.c
+++ b/backend/code11.c
@@ -1,7 +1,7 @@
 /* code11.c - Handles Code 11 */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -142,7 +142,7 @@ INTERNAL int zint_code11(struct zint_symbol *symbol, unsigned char source[], int
     memcpy(d, C11Table[11], 5);
     d += 5;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     /* TODO: Find documentation on BARCODE_CODE11 dimensions/height */
 
diff --git a/backend/code128.c b/backend/code128.c
index be8e7e9b..ef8343f0 100644
--- a/backend/code128.c
+++ b/backend/code128.c
@@ -336,7 +336,7 @@ static void c128_expand(struct zint_symbol *symbol, int values[C128_VALUES_MAX],
     }
 #endif
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 }
 
 /* Helper to set `priority` array based on flags */
diff --git a/backend/code16k.c b/backend/code16k.c
index df8bd9ee..c225843c 100644
--- a/backend/code16k.c
+++ b/backend/code16k.c
@@ -1,7 +1,7 @@
 /* code16k.c - Handles Code 16k stacked symbology */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -560,7 +560,7 @@ INTERNAL int zint_code16k(struct zint_symbol *symbol, unsigned char source[], in
         /* Write the information into the symbol */
         writer = 0;
         flip_flop = 1;
-        for (mx_reader = 0, len = d - width_pattern; mx_reader < len; mx_reader++) {
+        for (mx_reader = 0, len = (int) (d - width_pattern); mx_reader < len; mx_reader++) {
             for (looper = 0; looper < z_ctoi(width_pattern[mx_reader]); looper++) {
                 if (flip_flop == 1) {
                     z_set_module(symbol, current_row, writer);
diff --git a/backend/code49.c b/backend/code49.c
index 2ab1da02..8c460dc7 100644
--- a/backend/code49.c
+++ b/backend/code49.c
@@ -1,7 +1,7 @@
 /* code49.c - Handles Code 49 */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2009-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2009-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -79,7 +79,7 @@ INTERNAL int zint_code49(struct zint_symbol *symbol, unsigned char source[], int
 
     codeword_count = 0;
     i = 0;
-    h = d - intermediate;
+    h = (int) (d - intermediate);
     do {
         if (z_isdigit(intermediate[i])) {
             /* Numeric data */
diff --git a/backend/common.c b/backend/common.c
index ae40691b..d1cb326d 100644
--- a/backend/common.c
+++ b/backend/common.c
@@ -161,7 +161,7 @@ INTERNAL int z_posn(const char set_string[], const char data) {
 
     for (s = set_string; *s; s++) {
         if (data == *s) {
-            return s - set_string;
+            return (int) (s - set_string);
         }
     }
     return -1;
diff --git a/backend/gs1.c b/backend/gs1.c
index a2d38a47..93a31fc9 100644
--- a/backend/gs1.c
+++ b/backend/gs1.c
@@ -86,7 +86,7 @@ static int gs1_numeric(const unsigned char *data, int data_len, int offset, int
         for (; d < de; d++) {
             if (!z_isdigit(*d)) {
                 *p_err_no = 3;
-                *p_err_posn = d - data + 1;
+                *p_err_posn = (int) (d - data) + 1;
                 return gs1_err_msg_printf_nochk(err_msg, "Non-numeric character '%c'", *d);
             }
         }
@@ -136,7 +136,7 @@ static int gs1_cset82(const unsigned char *data, int data_len, int offset, int m
         for (; d < de; d++) {
             if (*d < '!' || *d > 'z' || gs1_c82[*d - '!'] == 82) {
                 *p_err_no = 3;
-                *p_err_posn = d - data + 1;
+                *p_err_posn = (int) (d - data) + 1;
                 return gs1_err_msg_printf_nochk(err_msg, "Invalid CSET 82 character '%c'", *d);
             }
         }
@@ -164,7 +164,7 @@ static int gs1_cset39(const unsigned char *data, int data_len, int offset, int m
             /* 0-9, A-Z and "#", "-", "/" */
             if ((*d < '0' && *d != '#' && *d != '-' && *d != '/') || (*d > '9' && *d < 'A') || *d > 'Z') {
                 *p_err_no = 3;
-                *p_err_posn = d - data + 1;
+                *p_err_posn = (int) (d - data) + 1;
                 return gs1_err_msg_printf_nochk(err_msg, "Invalid CSET 39 character '%c'", *d);
             }
         }
@@ -196,7 +196,7 @@ static int gs1_cset64(const unsigned char *data, int data_len, int offset, int m
                     break;
                 }
                 *p_err_no = 3;
-                *p_err_posn = d - data + 1;
+                *p_err_posn = (int) (d - data) + 1;
                 return gs1_err_msg_printf_nochk(err_msg, "Invalid CSET 64 character '%c'", *d);
             }
         }
@@ -232,7 +232,7 @@ static int gs1_csum(const unsigned char *data, int data_len, int offset, int min
         }
         if (checksum != *d - '0') {
             *p_err_no = 3;
-            *p_err_posn = d - data + 1;
+            *p_err_posn = (int) (d - data) + 1;
             return gs1_err_msg_printf_nochk(err_msg, "Bad checksum '%c', expected '%c'", *d, checksum + '0');
         }
     }
@@ -274,7 +274,7 @@ static int gs1_csumalpha(const unsigned char *data, int data_len, int offset, in
 
         if (de[0] != c1 || de[1] != c2) {
             *p_err_no = 3;
-            *p_err_posn = (de - data) + 1;
+            *p_err_posn = (int) (de - data) + 1;
             return gs1_err_msg_printf_nochk(err_msg, "Bad checksum '%.2s', expected '%c%c'", de, c1, c2);
         }
     }
@@ -665,12 +665,12 @@ static int gs1_pcenc(const unsigned char *data, int data_len, int offset, int mi
             if (*d == '%') {
                 if (de - d < 3) {
                     *p_err_no = 3;
-                    *p_err_posn = d - data + 1;
+                    *p_err_posn = (int) (d - data) + 1;
                     return gs1_err_msg_cpy_nochk(err_msg, "Invalid % escape");
                 }
                 if (strchr(hex_chars, *(++d)) == NULL || strchr(hex_chars, *(++d)) == NULL) {
                     *p_err_no = 3;
-                    *p_err_posn = d - data + 1;
+                    *p_err_posn = (int) (d - data) + 1;
                     return gs1_err_msg_cpy_nochk(err_msg, "Invalid character for percent encoding");
                 }
             }
@@ -858,19 +858,19 @@ static int gs1_iban(const unsigned char *data, int data_len, int offset, int min
         /* 1st 2 chars alphabetic country code */
         if (!z_isupper(d[0]) || !z_isupper(d[1])) {
             *p_err_no = 3;
-            *p_err_posn = d - data + 1;
+            *p_err_posn = (int) (d - data) + 1;
             return gs1_err_msg_printf_nochk(err_msg, "Non-alphabetic IBAN country code '%.2s'", d);
         }
         if (!iso3166_alpha2((const char *) d)) {
             *p_err_no = 3;
-            *p_err_posn = d - data + 1;
+            *p_err_posn = (int) (d - data) + 1;
             return gs1_err_msg_printf_nochk(err_msg, "Invalid IBAN country code '%.2s'", d);
         }
         d += 2;
         /* 2nd 2 chars numeric checksum */
         if (!z_isdigit(d[0]) || !z_isdigit(d[1])) {
             *p_err_no = 3;
-            *p_err_posn = d - data + 1;
+            *p_err_posn = (int) (d - data) + 1;
             return gs1_err_msg_printf_nochk(err_msg, "Non-numeric IBAN checksum '%.2s'", d);
         }
         given_checksum = z_to_int(d, 2);
@@ -879,7 +879,7 @@ static int gs1_iban(const unsigned char *data, int data_len, int offset, int min
             /* 0-9, A-Z */
             if (*d < '0' || (*d > '9' && *d < 'A') || *d > 'Z') {
                 *p_err_no = 3;
-                *p_err_posn = d - data + 1;
+                *p_err_posn = (int) (d - data) + 1;
                 return gs1_err_msg_printf_nochk(err_msg, "Invalid IBAN character '%c'", *d);
             }
             if (*d >= 'A') {
@@ -944,14 +944,14 @@ static const unsigned char *gs1_coupon_vli(const unsigned char *data, const int
 
     if (d - data + 1 > data_len) {
         *p_err_no = 3;
-        *p_err_posn = d - data + 1;
+        *p_err_posn = (int) (d - data) + 1;
         (void) gs1_err_msg_printf_nochk(err_msg, "%s VLI missing", name);
         return NULL;
     }
     vli = z_to_int(d, 1);
     if ((vli < vli_min || vli > vli_max) && (vli != 9 || !vli_nine)) {
         *p_err_no = 3;
-        *p_err_posn = d - data + 1;
+        *p_err_posn = (int) (d - data) + 1;
         if (vli < 0) {
             (void) gs1_err_msg_printf_nochk(err_msg, "Non-numeric %s VLI '%c'", name, *d);
         } else {
@@ -963,7 +963,7 @@ static const unsigned char *gs1_coupon_vli(const unsigned char *data, const int
     if (vli != 9 || !vli_nine) {
         if (d - data + vli + vli_offset > data_len) {
             *p_err_no = 3;
-            *p_err_posn = d - data + 1;
+            *p_err_posn = (int) (d - data) + 1;
             (void) gs1_err_msg_printf_nochk(err_msg, "%s incomplete", name);
             return NULL;
         }
@@ -971,7 +971,7 @@ static const unsigned char *gs1_coupon_vli(const unsigned char *data, const int
         for (; d < de; d++) {
             if (!z_isdigit(*d)) {
                 *p_err_no = 3;
-                *p_err_posn = d - data + 1;
+                *p_err_posn = (int) (d - data) + 1;
                 (void) gs1_err_msg_printf_nochk(err_msg, "Non-numeric %s '%c'", name, *d);
                 return NULL;
             }
@@ -988,14 +988,14 @@ static const unsigned char *gs1_coupon_val(const unsigned char *data, const int
 
     if (d - data + val_len > data_len) {
         *p_err_no = 3;
-        *p_err_posn = d - data + 1;
+        *p_err_posn = (int) (d - data) + 1;
         (void) gs1_err_msg_printf_nochk(err_msg, "%s incomplete", name);
         return NULL;
     }
     val = z_to_int(d, val_len);
     if (val < 0) {
         *p_err_no = 3;
-        *p_err_posn = d - data + 1;
+        *p_err_posn = (int) (d - data) + 1;
         (void) gs1_err_msg_printf_nochk(err_msg, "Non-numeric %s", name);
         return NULL;
     }
@@ -1059,7 +1059,7 @@ static int gs1_couponcode(const unsigned char *data, int data_len, int offset, i
         }
         if (val > 5 && val < 9) {
             *p_err_no = 3;
-            *p_err_posn = d - 1 - data + 1;
+            *p_err_posn = (int) (d - 1 - data) + 1;
             return gs1_err_msg_printf_nochk(err_msg, "Invalid Primary Purch. Req. Code '%c'", *(d - 1));
         }
         if (!(d = gs1_coupon_val(data, data_len, d, "Primary Purch. Family Code", 3, NULL, p_err_no, p_err_posn,
@@ -1080,7 +1080,7 @@ static int gs1_couponcode(const unsigned char *data, int data_len, int offset, i
                 }
                 if (val > 3) {
                     *p_err_no = 3;
-                    *p_err_posn = d - 1 - data + 1;
+                    *p_err_posn = (int) (d - 1 - data) + 1;
                     return gs1_err_msg_printf_nochk(err_msg, "Invalid Add. Purch. Rules Code '%c'", *(d - 1));
                 }
                 if (!(d = gs1_coupon_vli(data, data_len, d, "2nd Purch. Req.", 0, 1, 5, 0, p_err_no, p_err_posn,
@@ -1093,7 +1093,7 @@ static int gs1_couponcode(const unsigned char *data, int data_len, int offset, i
                 }
                 if (val > 4 && val < 9) {
                     *p_err_no = 3;
-                    *p_err_posn = d - 1 - data + 1;
+                    *p_err_posn = (int) (d - 1 - data) + 1;
                     return gs1_err_msg_printf_nochk(err_msg, "Invalid 2nd Purch. Req. Code '%c'", *(d - 1));
                 }
                 if (!(d = gs1_coupon_val(data, data_len, d, "2nd Purch. Family Code", 3, NULL, p_err_no, p_err_posn,
@@ -1117,7 +1117,7 @@ static int gs1_couponcode(const unsigned char *data, int data_len, int offset, i
                 }
                 if (val > 4 && val < 9) {
                     *p_err_no = 3;
-                    *p_err_posn = d - 1 - data + 1;
+                    *p_err_posn = (int) (d - 1 - data) + 1;
                     return gs1_err_msg_printf_nochk(err_msg, "Invalid 3rd Purch. Req. Code '%c'", *(d - 1));
                 }
                 if (!(d = gs1_coupon_val(data, data_len, d, "3rd Purch. Family Code", 3, NULL, p_err_no, p_err_posn,
@@ -1135,7 +1135,7 @@ static int gs1_couponcode(const unsigned char *data, int data_len, int offset, i
                                         err_msg))) {
                     return 0;
                 }
-                if (!gs1_yymmd0(data, data_len, d - 6 - data, 6, 6, p_err_no, p_err_posn, err_msg, 0)) {
+                if (!gs1_yymmd0(data, data_len, (int) (d - 6 - data), 6, 6, p_err_no, p_err_posn, err_msg, 0)) {
                     return 0;
                 }
 
@@ -1144,7 +1144,7 @@ static int gs1_couponcode(const unsigned char *data, int data_len, int offset, i
                 if (!(d = gs1_coupon_val(data, data_len, d, "Start Date", 6, NULL, p_err_no, p_err_posn, err_msg))) {
                     return 0;
                 }
-                if (!gs1_yymmd0(data, data_len, d - 6 - data, 6, 6, p_err_no, p_err_posn, err_msg, 0)) {
+                if (!gs1_yymmd0(data, data_len, (int) (d - 6 - data), 6, 6, p_err_no, p_err_posn, err_msg, 0)) {
                     return 0;
                 }
 
@@ -1170,7 +1170,7 @@ static int gs1_couponcode(const unsigned char *data, int data_len, int offset, i
                 }
                 if ((val > 2 && val < 5) || val > 6) {
                     *p_err_no = 3;
-                    *p_err_posn = d - 1 - data + 1;
+                    *p_err_posn = (int) (d - 1 - data) + 1;
                     return gs1_err_msg_printf_nochk(err_msg, "Invalid Save Value Code '%c'", *(d - 1));
                 }
                 if (!(d = gs1_coupon_val(data, data_len, d, "Save Value Applies To", 1, &val, p_err_no, p_err_posn,
@@ -1179,7 +1179,7 @@ static int gs1_couponcode(const unsigned char *data, int data_len, int offset, i
                 }
                 if (val > 2) {
                     *p_err_no = 3;
-                    *p_err_posn = d - 1 - data + 1;
+                    *p_err_posn = (int) (d - 1 - data) + 1;
                     return gs1_err_msg_printf_nochk(err_msg, "Invalid Save Value Applies To '%c'", *(d - 1));
                 }
                 if (!(d = gs1_coupon_val(data, data_len, d, "Store Coupon Flag", 1, NULL, p_err_no, p_err_posn,
@@ -1192,14 +1192,14 @@ static int gs1_couponcode(const unsigned char *data, int data_len, int offset, i
                 }
                 if (val > 1) {
                     *p_err_no = 3;
-                    *p_err_posn = d - 1 - data + 1;
+                    *p_err_posn = (int) (d - 1 - data) + 1;
                     return gs1_err_msg_printf_nochk(err_msg, "Invalid Don't Multiply Flag '%c'", *(d - 1));
                 }
 
             } else {
 
                 *p_err_no = 3;
-                *p_err_posn = d - 1 - data + 1;
+                *p_err_posn = (int) (d - 1 - data) + 1;
                 if (data_field < 0) {
                     (void) gs1_err_msg_printf_nochk(err_msg, "Non-numeric Data Field '%c'", *(d - 1));
                 } else {
@@ -1247,7 +1247,7 @@ static int gs1_couponposoffer(const unsigned char *data, int data_len, int offse
         }
         if (val != 0 && val != 1) {
             *p_err_no = 3;
-            *p_err_posn = d - 1 - data + 1;
+            *p_err_posn = (int) (d - 1 - data) + 1;
             return gs1_err_msg_cpy_nochk(err_msg, "Coupon Format must be 0 or 1");
         }
         if (!(d = gs1_coupon_vli(data, data_len, d, "Coupon Funder ID", 6, 0, 6, 0, p_err_no, p_err_posn, err_msg))) {
@@ -1261,7 +1261,7 @@ static int gs1_couponposoffer(const unsigned char *data, int data_len, int offse
         }
         if (d - data != data_len) {
             *p_err_no = 3;
-            *p_err_posn = d - data + 1;
+            *p_err_posn = (int) (d - data) + 1;
             return gs1_err_msg_cpy_nochk(err_msg, "Reserved trailing characters");
         }
     }
@@ -1290,7 +1290,7 @@ static int gs1_latitude(const unsigned char *data, int data_len, int offset, int
         }
         if (lat > 1800000000) {
             *p_err_no = 3;
-            *p_err_posn = d - 1 - data + 1;
+            *p_err_posn = (int) (d - 1 - data) + 1;
             return gs1_err_msg_cpy_nochk(err_msg, "Invalid latitude");
         }
     }
@@ -1319,7 +1319,7 @@ static int gs1_longitude(const unsigned char *data, int data_len, int offset, in
         }
         if (lng > 3600000000) {
             *p_err_no = 3;
-            *p_err_posn = d - 1 - data + 1;
+            *p_err_posn = (int) (d - 1 - data) + 1;
             return gs1_err_msg_cpy_nochk(err_msg, "Invalid longitude");
         }
     }
@@ -1348,7 +1348,7 @@ static int gs1_mediatype(const unsigned char *data, int data_len, int offset, in
         }
         if (val == 0 || (val > 10 && val < 80)) {
             *p_err_no = 3;
-            *p_err_posn = d - data + 1;
+            *p_err_posn = (int) (d - data) + 1;
             return gs1_err_msg_cpy_nochk(err_msg, "Invalid AIDC media type");
         }
     }
@@ -1373,7 +1373,7 @@ static int gs1_hyphen(const unsigned char *data, int data_len, int offset, int m
         for (; d < de; d++) {
             if (*d != '-') {
                 *p_err_no = 3;
-                *p_err_posn = d - data + 1;
+                *p_err_posn = (int) (d - data) + 1;
                 return gs1_err_msg_cpy_nochk(err_msg, "Invalid temperature indicator (hyphen only)");
             }
         }
@@ -1425,17 +1425,17 @@ static int gs1_posinseqslash(const unsigned char *data, int data_len, int offset
             if (!z_isdigit(*d)) {
                 if (*d != '/') {
                     *p_err_no = 3;
-                    *p_err_posn = d - data + 1;
+                    *p_err_posn = (int) (d - data) + 1;
                     return gs1_err_msg_printf_nochk(err_msg, "Invalid character '%c' in sequence", *d);
                 }
                 if (slash) {
                     *p_err_no = 3;
-                    *p_err_posn = d - data + 1;
+                    *p_err_posn = (int) (d - data) + 1;
                     return gs1_err_msg_cpy_nochk(err_msg, "Single sequence separator ('/') only");
                 }
                 if (d == data + offset || d + 1 == de) {
                     *p_err_no = 3;
-                    *p_err_posn = d - data + 1;
+                    *p_err_posn = (int) (d - data) + 1;
                     return gs1_err_msg_cpy_nochk(err_msg, "Sequence separator '/' cannot start or end");
                 }
                 slash = d;
@@ -1446,16 +1446,16 @@ static int gs1_posinseqslash(const unsigned char *data, int data_len, int offset
             *p_err_posn = offset + 1;
             return gs1_err_msg_cpy_nochk(err_msg, "No sequence separator ('/')");
         }
-        pos = z_to_int(data + offset, slash - (data + offset));
+        pos = z_to_int(data + offset, (int) (slash - (data + offset)));
         if (pos == 0) {
             *p_err_no = 3;
             *p_err_posn = offset + 1;
             return gs1_err_msg_cpy_nochk(err_msg, "Sequence position cannot be zero");
         }
-        tot = z_to_int(slash + 1, de - (slash + 1));
+        tot = z_to_int(slash + 1, (int) (de - (slash + 1)));
         if (tot == 0) {
             *p_err_no = 3;
-            *p_err_posn = slash + 1 - data + 1;
+            *p_err_posn = (int) (slash + 1 - data) + 1;
             return gs1_err_msg_cpy_nochk(err_msg, "Sequence total cannot be zero");
         }
         if (pos > tot) {
diff --git a/backend/mailmark.c b/backend/mailmark.c
index 9dfd95ed..cc91a4e3 100644
--- a/backend/mailmark.c
+++ b/backend/mailmark.c
@@ -1,7 +1,7 @@
 /* mailmark.c - Royal Mail 4-state and 2D Mailmark barcodes */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -467,7 +467,7 @@ INTERNAL int zint_mailmark_4s(struct zint_symbol *symbol, unsigned char source[]
 
     /* Translate 4-state data pattern to symbol */
     j = 0;
-    for (i = 0, len = d - bar; i < len; i++) {
+    for (i = 0, len = (int) (d - bar); i < len; i++) {
         if (bar[i] == 'F' || bar[i] == 'A') {
             z_set_module(symbol, 0, j);
         }
diff --git a/backend/medical.c b/backend/medical.c
index 2da52537..b1fc9979 100644
--- a/backend/medical.c
+++ b/backend/medical.c
@@ -83,14 +83,14 @@ INTERNAL int zint_pharma(struct zint_symbol *symbol, unsigned char source[], int
         }
     } while (tester != 0);
 
-    h = in - inter;
+    h = (int) (in - inter);
     for (counter = h - 1; counter >= 0; counter--) {
         *d++ = inter[counter] == 'W' ? '3' : '1';
         *d++ = '2';
     }
     *--d = '\0'; /* Chop off final bar */
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     if (symbol->output_options & COMPLIANT_HEIGHT) {
         /* Laetus Pharmacode Guide 1.2 Standard one-track height 8mm / 0.5mm (X) */
@@ -133,7 +133,7 @@ static int pharma_two_calc(int tester, char *d) {
         }
     } while (tester != 0);
 
-    h = in - inter;
+    h = (int) (in - inter);
     for (counter = h - 1; counter >= 0; counter--) {
         *d++ = inter[counter];
     }
diff --git a/backend/plessey.c b/backend/plessey.c
index 2d532155..9b411ba9 100644
--- a/backend/plessey.c
+++ b/backend/plessey.c
@@ -1,7 +1,7 @@
 /* plessey.c - Handles Plessey and MSI Plessey */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -116,7 +116,7 @@ INTERNAL int zint_plessey(struct zint_symbol *symbol, unsigned char source[], in
     memcpy(d, "331311313", 9);
     d += 9;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     /* TODO: Find documentation on BARCODE_PLESSEY dimensions/height */
 
@@ -375,7 +375,7 @@ INTERNAL int zint_msi_plessey(struct zint_symbol *symbol, unsigned char source[]
     memcpy(d, "121", 3);
     d += 3;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     /* TODO: Find documentation on BARCODE_MSI_PLESSEY dimensions/height */
 
diff --git a/backend/postal.c b/backend/postal.c
index 9d4bdc82..4fd0361b 100644
--- a/backend/postal.c
+++ b/backend/postal.c
@@ -1,7 +1,7 @@
 /* postal.c - Handles POSTNET, PLANET, CEPNet, FIM. RM4SCC and Flattermarken */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
     Including bug fixes by Bryan Hatton
 
     Redistribution and use in source and binary forms, with or without
@@ -330,7 +330,7 @@ INTERNAL int zint_koreapost(struct zint_symbol *symbol, unsigned char source[],
     memcpy(d, KoreaTable[check], 10);
     d += KoreaTable[check][8] ? 10 : 8;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     /* TODO: Find documentation on BARCODE_KOREAPOST dimensions/height */
 
@@ -557,7 +557,7 @@ INTERNAL int zint_kix(struct zint_symbol *symbol, unsigned char source[], int le
     }
 
     writer = 0;
-    h = d - height_pattern;
+    h = (int) (d - height_pattern);
     for (loopey = 0; loopey < h; loopey++) {
         if (height_pattern[loopey] == '1' || height_pattern[loopey] == '0') {
             z_set_module(symbol, 0, writer);
@@ -668,7 +668,7 @@ INTERNAL int zint_flat(struct zint_symbol *symbol, unsigned char source[], int l
         d += entry[2] ? 4 : 2;
     }
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     /* TODO: Find documentation on BARCODE_FLAT dimensions/height */
 
@@ -760,7 +760,7 @@ INTERNAL int zint_japanpost(struct zint_symbol *symbol, unsigned char source[],
 
     /* Resolve pattern to 4-state symbols */
     writer = 0;
-    h = d - pattern;
+    h = (int) (d - pattern);
     for (loopey = 0; loopey < h; loopey++) {
         if (pattern[loopey] == '2' || pattern[loopey] == '1') {
             z_set_module(symbol, 0, writer);
diff --git a/backend/telepen.c b/backend/telepen.c
index e5559d59..1e170566 100644
--- a/backend/telepen.c
+++ b/backend/telepen.c
@@ -1,7 +1,7 @@
 /* telepen.c - Handles Telepen and Telepen numeric */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -128,7 +128,7 @@ INTERNAL int zint_telepen(struct zint_symbol *symbol, unsigned char source[], in
     memcpy(d, TeleTable['z'], 12);
     d += 12;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     if (symbol->output_options & COMPLIANT_HEIGHT) {
         /* Default height from various Telepen docs is based on default 26pt at X 0.01125"
@@ -210,7 +210,7 @@ INTERNAL int zint_telepen_num(struct zint_symbol *symbol, unsigned char source[]
     memcpy(d, TeleTable['z'], 12);
     d += 12;
 
-    z_expand(symbol, dest, d - dest);
+    z_expand(symbol, dest, (int) (d - dest));
 
     if (symbol->output_options & COMPLIANT_HEIGHT) {
         (void) z_set_height(symbol, 0.0f, 32.0f, 0, 1 /*no_errtxt*/); /* Same as alphanumeric Telepen */
diff --git a/backend/tests/test_bwipp.c b/backend/tests/test_bwipp.c
index cce26ab3..28485cb7 100644
--- a/backend/tests/test_bwipp.c
+++ b/backend/tests/test_bwipp.c
@@ -111,7 +111,7 @@ static void test_bwipp_random(const testCtx *const p_ctx, const struct random_it
                     bwipp_buf, sizeof(bwipp_buf), NULL);
         assert_zero(ret, "i:%d %s testUtilBwipp ret %d != 0\n", i, testUtilBarcodeName(symbol->symbology), ret);
 
-        bwipp_len = strlen(bwipp_buf);
+        bwipp_len = (int) strlen(bwipp_buf);
         assert_nonzero(bwipp_len, "i:%d bwipp_len %d = 0\n", i, bwipp_len);
 
         symbol->width = width_func ? width_func(rdata, bwipp_len) : bwipp_len;
@@ -405,7 +405,7 @@ static void test_aztec_bwipjs_354(const testCtx *const p_ctx) {
                     sizeof(bwipp_buf), NULL);
         assert_zero(ret, "i:%d %s testUtilBwipp ret %d != 0\n", i, testUtilBarcodeName(symbol->symbology), ret);
 
-        bwipp_len = strlen(bwipp_buf);
+        bwipp_len = (int) strlen(bwipp_buf);
         assert_nonzero(bwipp_len, "i:%d bwipp_len %d = 0\n", i, bwipp_len);
 
         symbol->width = sqrt_width_func(NULL /*rdata*/, bwipp_len);
@@ -496,7 +496,7 @@ static void test_codablockf_fnc4_digit(const testCtx *const p_ctx) {
                     bwipp_buf, sizeof(bwipp_buf), NULL);
         assert_zero(ret, "i:%d %s testUtilBwipp ret %d != 0\n", i, testUtilBarcodeName(symbol->symbology), ret);
 
-        bwipp_len = strlen(bwipp_buf);
+        bwipp_len = (int) strlen(bwipp_buf);
         assert_nonzero(bwipp_len, "i:%d bwipp_len %d = 0\n", i, bwipp_len);
 
         symbol->width = codablockf_width_func(rdata, bwipp_len);
diff --git a/backend/tests/test_library.c b/backend/tests/test_library.c
index 26d8fe77..0cd433ab 100644
--- a/backend/tests/test_library.c
+++ b/backend/tests/test_library.c
@@ -1468,7 +1468,7 @@ static void test_encode_file_unreadable(const testCtx *const p_ctx) {
     fd = creat(filename, S_IWUSR);
     assert_notequal(fd, -1, "Unreadable input file (%s) not created == -1 (%d: %s)\n",
                 filename, errno, strerror(errno));
-    ret = write(fd, buf, 1);
+    ret = (int) write(fd, buf, 1);
     assert_equal(ret, 1, "Unreadable write ret %d != 1\n", ret);
     ret = close(fd);
     assert_zero(ret, "Unreadable close(%s) != 0(%d: %s)\n", filename, errno, strerror(errno));
diff --git a/backend/tests/testcommon.c b/backend/tests/testcommon.c
index df499aa7..bc6d00d7 100644
--- a/backend/tests/testcommon.c
+++ b/backend/tests/testcommon.c
@@ -1182,7 +1182,7 @@ int testUtilModulesDump(const struct zint_symbol *symbol, char dump[], int dump_
         return -1;
     }
     *d = '\0';
-    return d - dump;
+    return (int) (d - dump);
 }
 
 /* Print out module dump (for generate tests) */
@@ -1492,24 +1492,24 @@ int testUtilDataPath(char *buffer, int buffer_size, const char *subdir, const ch
             s = s2;
         }
         *s = '\0';
-        len = s - buffer;
+        len = (int) (s - buffer);
     }
     if ((s = strstr(buffer, "/backend")) != NULL) {
         while ((s2 = strstr(s + 1, "/backend")) != NULL) { /* Find rightmost */
             s = s2;
         }
         *s = '\0';
-        len = s - buffer;
+        len = (int) (s - buffer);
     } else if ((s = strstr(buffer, "/frontend")) != NULL) {
         while ((s2 = strstr(s + 1, "/frontend")) != NULL) { /* Find rightmost */
             s = s2;
         }
         *s = '\0';
-        len = s - buffer;
+        len = (int) (s - buffer);
     }
     if (cmake_src_dir == NULL && (s = strrchr(buffer, '/')) != NULL) { /* Remove "build" dir */
         *s = '\0';
-        len = s - buffer;
+        len = (int) (s - buffer);
     }
 
     if (subdir_len) {
@@ -2196,7 +2196,7 @@ int testUtilVerifyLibreOffice(const char *filename, int debug) {
         return -1;
     }
     while (!feof(fp) && b < be) {
-        if (fgets(b, be - b, fp) == NULL) {
+        if (fgets(b, (int) (be - b), fp) == NULL) {
             fprintf(stderr, "testUtilVerifyLibreOffice: failed to get line from '%s' (%s)\n", svg, cmd);
             fclose(fp);
             return -1;
@@ -2642,7 +2642,7 @@ static char *testUtilBwippCvtGS1Data(char *bwipp_data, const int bwipp_data_size
                 *b = ')';
             } else if ((*c == '+' || *c == ' ') && upcean && !pipe) {
                 *b = ' ';
-                *addon_posn = b - bwipp_data;
+                *addon_posn = (int) (b - bwipp_data);
             } else {
                 *b = *c;
             }
@@ -3780,7 +3780,7 @@ int testUtilBwippSegs(int index, struct zint_symbol *symbol, int option_1, int o
             d += local_segs[i].length;
         }
     }
-    total_len = d - data;
+    total_len = (int) (d - data);
 
     if (unicode_mode) {
         symbol->input_mode = DATA_MODE;
@@ -4273,7 +4273,7 @@ static int textUtilZXingCPPDX(const char *expected, const int expected_len, cons
 static int textUtilZXingCPPEAN13AddOn(const char *expected, const int expected_len, char *out) {
     char *sep;
     if ((sep = strchr(expected, '+')) != NULL || (sep = strchr(expected, ' ')) != NULL) {
-        const int addon_len = expected_len - (sep + 1 - expected);
+        const int addon_len = expected_len - (int) (sep + 1 - expected);
         if (addon_len <= 2) {
             memset(out + 13, '0', 2 - addon_len);
             memcpy(out + 13 + (2 - addon_len), sep + 1, addon_len);
diff --git a/backend/tif.c b/backend/tif.c
index f71cfb1a..8bc6c209 100644
--- a/backend/tif.c
+++ b/backend/tif.c
@@ -1,7 +1,7 @@
 /* tif.c - Aldus Tagged Image File Format support */
 /*
     libzint - the open source barcode library
-    Copyright (C) 2016-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2016-2026 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -376,7 +376,7 @@ INTERNAL int zint_tif_pixel_plot(struct zint_symbol *symbol, const unsigned char
                     (void) zint_fm_close(fmp, symbol);
                     return z_errtxt(ZINT_ERROR_MEMORY, symbol, 673, "Insufficient memory for TIF LZW hash table");
                 }
-                bytes_put = zint_fm_tell(fmp) - file_pos;
+                bytes_put = (unsigned int) (zint_fm_tell(fmp) - file_pos);
                 if (bytes_put != strip_bytes[strip]) {
                     const int diff = bytes_put - strip_bytes[strip];
                     strip_bytes[strip] = bytes_put;