diff --git a/src/Errors.h b/src/Errors.h
index 5cd753fb7..6d547ca31 100644
--- a/src/Errors.h
+++ b/src/Errors.h
@@ -7,7 +7,7 @@
 /* NOTE: When changing these, remember to keep Logger.C up to date! */
 enum ERRORS_ALL {
 	ERROR_BASE = 0xCCDED000UL,
-	ERR_END_OF_STREAM,
+	ERR_END_OF_STREAM, ERR_NOT_SUPPORTED, ERR_INVALID_ARGUMENT,
 
 	/* Ogg stream decoding errors */
 	OGG_ERR_INVALID_SIG, OGG_ERR_VERSION,
diff --git a/src/Logger.c b/src/Logger.c
index 057354047..b446f29d5 100644
--- a/src/Logger.c
+++ b/src/Logger.c
@@ -73,9 +73,11 @@ void Logger_OldWarn2(ReturnCode res, const char* place, const String* path) {
 /* Returns a description for ClassiCube specific error codes */
 static const char* Logger_GetCCErrorDesc(ReturnCode res) {
 	switch (res) {
-	case ERR_END_OF_STREAM:   return "End of stream";
-	case OGG_ERR_INVALID_SIG: return "Invalid OGG signature";
-	case OGG_ERR_VERSION:     return "Invalid OGG format version";
+	case ERR_END_OF_STREAM:    return "End of stream";
+	case ERR_NOT_SUPPORTED:    return "Operation not supported";
+	case ERR_INVALID_ARGUMENT: return "Invalid argument";
+	case OGG_ERR_INVALID_SIG:  return "Invalid OGG signature";
+	case OGG_ERR_VERSION:      return "Invalid OGG format version";
 
 	case WAV_ERR_STREAM_HDR:  return "Invalid WAV header";
 	case WAV_ERR_STREAM_TYPE: return "Invalid WAV type";
diff --git a/src/Platform.c b/src/Platform.c
index d2a6e7aed..58c4a7f28 100644
--- a/src/Platform.c
+++ b/src/Platform.c
@@ -7,6 +7,7 @@
 #include "Bitmap.h"
 #include "Window.h"
 #include "Utils.h"
+#include "Errors.h"
 #define CC_BUILD_FREETYPE
 
 #if defined CC_BUILD_WIN
@@ -37,9 +38,7 @@ static HANDLE heap;
 const char* Platform_NewLine = "\r\n";
 
 const ReturnCode ReturnCode_FileShareViolation = ERROR_SHARING_VIOLATION;
-const ReturnCode ReturnCode_FileNotFound = ERROR_FILE_NOT_FOUND;
-const ReturnCode ReturnCode_NotSupported = ERROR_NOT_SUPPORTED;
-const ReturnCode ReturnCode_InvalidArg   = ERROR_INVALID_PARAMETER;
+const ReturnCode ReturnCode_FileNotFound     = ERROR_FILE_NOT_FOUND;
 const ReturnCode ReturnCode_SocketInProgess  = WSAEINPROGRESS;
 const ReturnCode ReturnCode_SocketWouldBlock = WSAEWOULDBLOCK;
 #elif defined CC_BUILD_POSIX
@@ -68,9 +67,7 @@ const ReturnCode ReturnCode_SocketWouldBlock = WSAEWOULDBLOCK;
 const char* Platform_NewLine = "\n";
 
 const ReturnCode ReturnCode_FileShareViolation = 1000000000; /* TODO: not used apparently */
-const ReturnCode ReturnCode_FileNotFound = ENOENT;
-const ReturnCode ReturnCode_NotSupported = EPERM;
-const ReturnCode ReturnCode_InvalidArg   = EINVAL;
+const ReturnCode ReturnCode_FileNotFound     = ENOENT;
 const ReturnCode ReturnCode_SocketInProgess  = EINPROGRESS;
 const ReturnCode ReturnCode_SocketWouldBlock = EWOULDBLOCK;
 #endif
@@ -1353,7 +1350,7 @@ ReturnCode Socket_Available(SocketHandle socket, uint32_t* available) {
 }
 ReturnCode Socket_SetBlocking(SocketHandle socket, bool blocking) {
 #if defined CC_BUILD_WEB
-	return ReturnCode_NotSupported; /* sockets always async */
+	return ERR_NOT_SUPPORTED; /* sockets always async */
 #else
 	int blocking_raw = blocking ? 0 : -1;
 	return Socket_ioctl(socket, FIONBIO, &blocking_raw);
@@ -1545,8 +1542,8 @@ bool DynamicLib_DescribeError(ReturnCode res, String* dst) {
 	return Platform_DescribeError(res, dst);
 }
 #elif defined CC_BUILD_WEB
-ReturnCode Process_GetExePath(String* path) { return ReturnCode_NotSupported; }
-ReturnCode Process_Start(const String* path, const String* args) { return ReturnCode_NotSupported; }
+ReturnCode Process_GetExePath(String* path) { return ERR_NOT_SUPPORTED; }
+ReturnCode Process_Start(const String* path, const String* args) { return ERR_NOT_SUPPORTED; }
 
 ReturnCode Process_StartOpen(const String* args) {
 	char str[600];
@@ -1555,8 +1552,8 @@ ReturnCode Process_StartOpen(const String* args) {
 }
 void Process_Exit(ReturnCode code) { exit(code); }
 
-ReturnCode DynamicLib_Load(const String* path, void** lib) { return ReturnCode_NotSupported; }
-ReturnCode DynamicLib_Get(void* lib, const char* name, void** symbol) { return ReturnCode_NotSupported; }
+ReturnCode DynamicLib_Load(const String* path, void** lib) { return ERR_NOT_SUPPORTED; }
+ReturnCode DynamicLib_Get(void* lib, const char* name, void** symbol) { return ERR_NOT_SUPPORTED; }
 bool DynamicLib_DescribeError(ReturnCode res, String* dst) { return false; }
 #elif defined CC_BUILD_POSIX
 ReturnCode Process_Start(const String* path, const String* args) {
@@ -1623,7 +1620,7 @@ ReturnCode Process_GetExePath(String* path) {
 	char str[600];
 	int len = 600;
 
-	if (_NSGetExecutablePath(str, &len) != 0) return ReturnCode_InvalidArg;
+	if (_NSGetExecutablePath(str, &len)) return ERR_INVALID_ARGUMENT;
 	Convert_DecodeUtf8(path, str, len);
 	return 0;
 }
@@ -1906,10 +1903,10 @@ int Platform_GetCommandLineArgs(int argc, STRING_REF const char** argv, String*
 }
 
 ReturnCode Platform_Encrypt(const uint8_t* data, int len, uint8_t** enc, int* encLen) {
-	return ReturnCode_NotSupported;
+	return ERR_NOT_SUPPORTED;
 }
 ReturnCode Platform_Decrypt(const uint8_t* data, int len, uint8_t** dec, int* decLen) {
-	return ReturnCode_NotSupported;
+	return ERR_NOT_SUPPORTED;
 }
 
 bool Platform_DescribeError(ReturnCode res, String* dst) {
diff --git a/src/Platform.h b/src/Platform.h
index ade67253b..dedf1ef79 100644
--- a/src/Platform.h
+++ b/src/Platform.h
@@ -27,10 +27,8 @@ enum File_SeekFrom { FILE_SEEKFROM_BEGIN, FILE_SEEKFROM_CURRENT, FILE_SEEKFROM_E
 extern const char* Platform_NewLine;
 extern const ReturnCode ReturnCode_FileShareViolation;
 extern const ReturnCode ReturnCode_FileNotFound;
-extern const ReturnCode ReturnCode_NotSupported;
 extern const ReturnCode ReturnCode_SocketInProgess;
 extern const ReturnCode ReturnCode_SocketWouldBlock;
-extern const ReturnCode ReturnCode_InvalidArg;
 
 /* Encodes a string in platform specific format. (e.g. unicode on windows, UTF8 on linux) */
 /* NOTE: Only useful for platform specific function calls - do NOT try to interpret the data. */
diff --git a/src/Resources.c b/src/Resources.c
index af15952d2..44beabb6e 100644
--- a/src/Resources.c
+++ b/src/Resources.c
@@ -734,7 +734,7 @@ CC_NOINLINE static bool Fetcher_Get(const String* id, struct HttpRequest* req) {
 		Fetcher_Finish();
 		return false;
 	} else if (!req->Data) {
-		Fetcher_Error = ReturnCode_InvalidArg;
+		Fetcher_Error = ERR_INVALID_ARGUMENT;
 		Fetcher_Finish();
 		return false;
 	}
diff --git a/src/Stream.c b/src/Stream.c
index 188411a12..928f602cb 100644
--- a/src/Stream.c
+++ b/src/Stream.c
@@ -37,10 +37,10 @@ ReturnCode Stream_Write(struct Stream* s, const uint8_t* buffer, uint32_t count)
 }
 
 static ReturnCode Stream_DefaultRead(struct Stream* s, uint8_t* data, uint32_t count, uint32_t* modified) {
-	return ReturnCode_NotSupported;
+	return ERR_NOT_SUPPORTED;
 }
 static ReturnCode Stream_DefaultWrite(struct Stream* s, const uint8_t* data, uint32_t count, uint32_t* modified) {
-	return ReturnCode_NotSupported;
+	return ERR_NOT_SUPPORTED;
 }
 ReturnCode Stream_DefaultReadU8(struct Stream* s, uint8_t* data) {
 	uint32_t modified;
@@ -64,10 +64,10 @@ static ReturnCode Stream_DefaultSkip(struct Stream* s, uint32_t count) {
 }
 
 static ReturnCode Stream_DefaultSeek(struct Stream* s, uint32_t pos) {
-	return ReturnCode_NotSupported; 
+	return ERR_NOT_SUPPORTED;
 }
 static ReturnCode Stream_DefaultGet(struct Stream* s, uint32_t* value) { 
-	return ReturnCode_NotSupported; 
+	return ERR_NOT_SUPPORTED;
 }
 static ReturnCode Stream_DefaultClose(struct Stream* s) { return 0; }
 
@@ -179,7 +179,7 @@ static ReturnCode Stream_PortionSkip(struct Stream* s, uint32_t count) {
 	struct Stream* source;
 	ReturnCode res;
 
-	if (count > s->Meta.Portion.Left) return ReturnCode_InvalidArg;
+	if (count > s->Meta.Portion.Left) return ERR_INVALID_ARGUMENT;
 	source = s->Meta.Portion.Source;
 
 	res = source->Skip(source, count);
@@ -241,7 +241,7 @@ static ReturnCode Stream_MemoryWrite(struct Stream* s, const uint8_t* data, uint
 }
 
 static ReturnCode Stream_MemorySkip(struct Stream* s, uint32_t count) {
-	if (count > s->Meta.Mem.Left) return ReturnCode_InvalidArg;
+	if (count > s->Meta.Mem.Left) return ERR_INVALID_ARGUMENT;
 
 	s->Meta.Mem.Cur  += count; 
 	s->Meta.Mem.Left -= count;
@@ -249,7 +249,7 @@ static ReturnCode Stream_MemorySkip(struct Stream* s, uint32_t count) {
 }
 
 static ReturnCode Stream_MemorySeek(struct Stream* s, uint32_t position) {
-	if (position >= s->Meta.Mem.Length) return ReturnCode_InvalidArg;
+	if (position >= s->Meta.Mem.Length) return ERR_INVALID_ARGUMENT;
 
 	s->Meta.Mem.Cur  = s->Meta.Mem.Base   + position;
 	s->Meta.Mem.Left = s->Meta.Mem.Length - position;
diff --git a/src/Vorbis.c b/src/Vorbis.c
index f9d3c116c..ed39719af 100644
--- a/src/Vorbis.c
+++ b/src/Vorbis.c
@@ -1103,7 +1103,7 @@ static ReturnCode Vorbis_CheckHeader(struct VorbisState* ctx, uint8_t type) {
 	OK = 
 		header[1] == 'v' && header[2] == 'o' && header[3] == 'r' &&
 		header[4] == 'b' && header[5] == 'i' && header[6] == 's';
-	return OK ? 0 : ReturnCode_InvalidArg;
+	return OK ? 0 : ERR_INVALID_ARGUMENT;
 }
 
 static ReturnCode Vorbis_DecodeIdentifier(struct VorbisState* ctx) {