diff --git a/linux/src/open_file_dialog.cc b/linux/src/open_file_dialog.cc
index 45513ce..368112b 100644
--- a/linux/src/open_file_dialog.cc
+++ b/linux/src/open_file_dialog.cc
@@ -1,4 +1,5 @@
 #include "open_file_dialog.h"
+#include "compat.h"
 #include <gtk/gtk.h>
 #include <cstring>
 #include <vector>
@@ -68,11 +69,11 @@ std::vector<std::string> open_file_dialog(const std::string &title, const std::s
     return result;
 }
 
-int open_file_dialog(char *rom_name) {
+int open_file_dialog(char *rom_filepath) {
     std::vector<std::string> fileTypes = {"ch8", "CH8", "chip-8", "CHIP-8", "Chip-8"};
     const char* defaultDir = ""; // unify behavior: let OS choose last-used/home
     std::vector<std::string> files = open_file_dialog("Chip8", defaultDir, fileTypes);
     if (files.empty()) return 1;
-    snprintf(rom_name, 256, "%s", files[0].c_str());
+    snprintf(rom_filepath, PATH_MAX, "%s", files[0].c_str());
     return 0;
 }
diff --git a/macos/src/open_file_dialog.mm b/macos/src/open_file_dialog.mm
index 2e5e422..adf60c8 100644
--- a/macos/src/open_file_dialog.mm
+++ b/macos/src/open_file_dialog.mm
@@ -1,4 +1,5 @@
 #import "open_file_dialog.h"
+#import "compat.h"
 #import <Foundation/Foundation.h>
 #import <Cocoa/Cocoa.h>
 #include <string>
@@ -43,11 +44,11 @@
     return fileList;
 }
 
-int open_file_dialog(char *rom_name) {
+int open_file_dialog(char *rom_filepath) {
     std::vector<std::string> fileTypes = {"ch8", "CH8", "chip-8", "CHIP-8", "Chip-8"};
     const char* defaultDir = ""; // unify behavior: let OS choose last-used/home
     std::vector<std::string> files = open_file_dialog("Chip8", defaultDir, fileTypes);
     if (files.empty()) return 1;
-    snprintf(rom_name, 256, "%s", files[0].c_str());
+    snprintf(rom_filepath, PATH_MAX, "%s", files[0].c_str());
     return 0;
 }
diff --git a/shared/chip8.c b/shared/chip8.c
index d472b34..08a7199 100644
--- a/shared/chip8.c
+++ b/shared/chip8.c
@@ -7,6 +7,7 @@
 #include "profiles.h"
 #include "sha256.h"
 #include "toast.h"
+#include "compat.h"
 #include "open_file_dialog.h"
 #include <SDL2/SDL.h>
 #include <stdio.h>
@@ -193,10 +194,10 @@ int chip8_load_rom(const char *rom_filepath) {
 
     } else {
         /* load ROM from GUI */
-        char new_rom_name[PATH_MAX];
-        open_file_dialog(new_rom_name) ?
+        char new_rom_filepath[PATH_MAX];
+        open_file_dialog(new_rom_filepath) ?
             printf("User aborted the open file dialog.\n") :
-            chip8_load_rom(new_rom_name);
+            chip8_load_rom(new_rom_filepath);
 
         /* flip GUI toggle */
         gui.load_rom_flag = 0;
diff --git a/shared/chip8.h b/shared/chip8.h
index be65d98..2ef4f5e 100644
--- a/shared/chip8.h
+++ b/shared/chip8.h
@@ -5,6 +5,7 @@
 extern "C" {
 #endif
 
+#include "compat.h"
 #include "bootrom.h" // Generated at build time from roms/Kiwi8_logo_2.ch8
 #include "quirks.h"
 #include <stdlib.h>
@@ -62,7 +63,7 @@ struct chip8 {
     unsigned int rom_size;
 
     /* rom profile tracking */
-    char rom_filename[256];  /* basename of currently loaded ROM */
+    char rom_filename[FILENAME_MAX];  /* basename of currently loaded ROM */
     int rom_loaded;          /* 1 if user ROM loaded, 0 if bootrom */
 
     /* registers */
diff --git a/shared/compat.h b/shared/compat.h
new file mode 100644
index 0000000..9feeb8c
--- /dev/null
+++ b/shared/compat.h
@@ -0,0 +1,28 @@
+#ifndef COMPAT_H
+#define COMPAT_H
+
+#include <limits.h>
+
+// Handle missing PATH_MAX on some systems
+#if defined(__APPLE__)
+    #include <sys/syslimits.h>
+#elif defined(__linux__)
+    #include <linux/limits.h>
+#elif defined(_WIN32)
+    #include <windows.h>
+    #ifndef PATH_MAX
+        #define PATH_MAX MAX_PATH
+    #endif
+#endif
+
+#ifndef PATH_MAX
+    #define PATH_MAX 4096
+#endif
+#ifndef FILENAME_MAX
+    #define FILENAME_MAX 256
+#endif
+#ifndef LINE_MAX
+    #define LINE_MAX 2048
+#endif
+
+#endif // COMPAT_H
diff --git a/shared/open_file_dialog.h b/shared/open_file_dialog.h
index a0837b3..bcfabcb 100644
--- a/shared/open_file_dialog.h
+++ b/shared/open_file_dialog.h
@@ -5,23 +5,10 @@
 extern "C" {
 #endif
 
-#ifdef __APPLE__
-#include <limits.h> /* PATH_MAX */
-#endif
-
-#ifdef _WIN32
-#include <windows.h> /* MAX_PATH */
-#define PATH_MAX MAX_PATH
-#endif
-
-#ifdef __linux__
-#include <limits.h> /* PATH_MAX */
-#endif
-
-int open_file_dialog(char *rom_name);
+int open_file_dialog(char *rom_filepath);
 
 #ifdef __cplusplus
 }
 #endif
 
-#endif
+#endif // OPEN_FILE_DIALOG_H
diff --git a/shared/profiles.c b/shared/profiles.c
index 2fd080f..b00d1f7 100644
--- a/shared/profiles.c
+++ b/shared/profiles.c
@@ -1,4 +1,5 @@
 #include "profiles.h"
+#include "compat.h"
 #define STB_DS_IMPLEMENTATION
 #include "stb_ds.h"
 #include "sha256.h"
@@ -13,7 +14,7 @@
 static struct { sha256_hash_t key; struct profile value; } *profile_map = NULL;
 
 /* Track which path we loaded profiles.ini from */
-static char loaded_profiles_path[512] = "";
+static char loaded_profiles_path[FILENAME_MAX] = "";
 
 /* Quirk field descriptor table — generated from QUIRK_FIELDS X-macro in quirks.h */
 static const struct {
@@ -58,7 +59,7 @@ static void parse_profiles_ini(void) {
     FILE *file = fopen(loaded_profiles_path, "r");
     if (!file) return;
 
-    char line[512];
+    char line[LINE_MAX];
     sha256_hash_t current_sha256 = {0};
     int has_current = 0;
     struct profile current_profile;
@@ -164,7 +165,7 @@ static int resolve_profiles_path(void) {
     }
 
     /* Build search paths relative to executable */
-    char search_paths[2][512];
+    char search_paths[2][LINE_MAX];
     char *base_path = SDL_GetBasePath();
     if (!base_path) {
         printf("Warning: Could not determine executable path. Trying current directory.\n");
diff --git a/shared/profiles.h b/shared/profiles.h
index 59d6602..687d5e6 100644
--- a/shared/profiles.h
+++ b/shared/profiles.h
@@ -8,12 +8,13 @@ extern "C" {
 #include <stdint.h>
 #include "quirks.h"
 #include "sha256.h"
+#include "compat.h"
 
 typedef struct { uint8_t bytes[32]; } sha256_hash_t;
 
 struct profile {
     sha256_hash_t sha256;
-    char rom_name[256];
+    char rom_name[FILENAME_MAX];
     struct quirks quirks;
 };
 
diff --git a/shared/usage.h b/shared/usage.h
index 17d98e7..db40a55 100644
--- a/shared/usage.h
+++ b/shared/usage.h
@@ -1,6 +1,10 @@
 #ifndef USAGE_H
 #define USAGE_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Centralized usage/help text for CLI and GUI */
 static const char *USAGE_TEXT =
     "Usage: Kiwi8 [options] [rom_file]\n"
@@ -12,4 +16,8 @@ static const char *USAGE_TEXT =
     "\n"
     "Note: Quirks are configured per-ROM via profiles.ini or GUI.\n";
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* USAGE_H */
diff --git a/windows/src/open_file_dialog.cc b/windows/src/open_file_dialog.cc
index b85e087..459715f 100644
--- a/windows/src/open_file_dialog.cc
+++ b/windows/src/open_file_dialog.cc
@@ -1,17 +1,18 @@
 #include "open_file_dialog.h"
+#include "compat.h"
 #include <windows.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-int open_file_dialog(char *rom_name, char *filters) {
+int open_file_dialog(char *rom_filepath, char *filters) {
     /* open file dialogue */
-    char cwd[MAX_PATH];
-    GetCurrentDirectory(MAX_PATH, cwd);
+    char cwd[PATH_MAX];
+    GetCurrentDirectory(PATH_MAX, cwd);
 
     OPENFILENAME ofn;
 
-    char szFile[MAX_PATH];
+    char szFile[PATH_MAX];
 
     /* open a file name */
     ZeroMemory( &ofn , sizeof( ofn));
@@ -35,10 +36,10 @@ int open_file_dialog(char *rom_name, char *filters) {
         return 1;
     }
 
-    strcpy(rom_name, szFile);
+    strcpy(rom_filepath, szFile);
     return 0;
 }
 
-int open_file_dialog(char *rom_name) {
-    return open_file_dialog(rom_name, "Chip8\0*.ch8\0All\0*.*\0");
+int open_file_dialog(char *rom_filepath) {
+    return open_file_dialog(rom_filepath, "Chip8\0*.ch8\0All\0*.*\0");
 }