diff --git a/code/AssetLib/3DS/3DSLoader.cpp b/code/AssetLib/3DS/3DSLoader.cpp
index b690f557d..89a4fbc7e 100644
--- a/code/AssetLib/3DS/3DSLoader.cpp
+++ b/code/AssetLib/3DS/3DSLoader.cpp
@@ -113,7 +113,7 @@ Discreet3DSImporter::~Discreet3DSImporter() {
 // Returns whether the class can handle the format of the given file.
 bool Discreet3DSImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const uint16_t token[] = { 0x4d4d, 0x3dc2 /*, 0x3daa */ };
-    return CheckMagicToken(pIOHandler, pFile, token, std::size(token), 0, sizeof token[0]);
+    return CheckMagicToken(pIOHandler, pFile, token, AI_COUNT_OF(token), 0, sizeof token[0]);
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/AC/ACLoader.cpp b/code/AssetLib/AC/ACLoader.cpp
index c259b2eb0..ea097ae0d 100644
--- a/code/AssetLib/AC/ACLoader.cpp
+++ b/code/AssetLib/AC/ACLoader.cpp
@@ -154,7 +154,7 @@ AC3DImporter::~AC3DImporter() {
 // Returns whether the class can handle the format of the given file.
 bool AC3DImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const uint32_t tokens[] = { AI_MAKE_MAGIC("AC3D") };
-    return CheckMagicToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return CheckMagicToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/AMF/AMFImporter.cpp b/code/AssetLib/AMF/AMFImporter.cpp
index 0cc02a2c7..9e846d473 100644
--- a/code/AssetLib/AMF/AMFImporter.cpp
+++ b/code/AssetLib/AMF/AMFImporter.cpp
@@ -504,7 +504,7 @@ void AMFImporter::ParseNode_Metadata(XmlNode &node) {
 
 bool AMFImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*pCheckSig*/) const {
     static const char *tokens[] = { "<amf" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 const aiImporterDesc *AMFImporter::GetInfo() const {
diff --git a/code/AssetLib/ASE/ASELoader.cpp b/code/AssetLib/ASE/ASELoader.cpp
index e950290c7..d67da609e 100644
--- a/code/AssetLib/ASE/ASELoader.cpp
+++ b/code/AssetLib/ASE/ASELoader.cpp
@@ -99,7 +99,7 @@ ASEImporter::~ASEImporter() {
 // Returns whether the class can handle the format of the given file.
 bool ASEImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const char *tokens[] = { "*3dsmax_asciiexport" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/BVH/BVHLoader.cpp b/code/AssetLib/BVH/BVHLoader.cpp
index d6d75ba21..478674486 100644
--- a/code/AssetLib/BVH/BVHLoader.cpp
+++ b/code/AssetLib/BVH/BVHLoader.cpp
@@ -94,7 +94,7 @@ BVHLoader::~BVHLoader() {}
 // Returns whether the class can handle the format of the given file.
 bool BVHLoader::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const char *tokens[] = { "HIERARCHY" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/Blender/BlenderLoader.cpp b/code/AssetLib/Blender/BlenderLoader.cpp
index 4c34d11e0..71514d28b 100644
--- a/code/AssetLib/Blender/BlenderLoader.cpp
+++ b/code/AssetLib/Blender/BlenderLoader.cpp
@@ -120,7 +120,7 @@ static const char *TokensForSearch[] = { "blender" };
 // Returns whether the class can handle the format of the given file.
 bool BlenderImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     // note: this won't catch compressed files
-    return SearchFileHeaderForToken(pIOHandler, pFile, TokensForSearch, std::size(TokensForSearch));
+    return SearchFileHeaderForToken(pIOHandler, pFile, TokensForSearch, AI_COUNT_OF(TokensForSearch));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/COB/COBLoader.cpp b/code/AssetLib/COB/COBLoader.cpp
index 5d897d439..97fed04c0 100644
--- a/code/AssetLib/COB/COBLoader.cpp
+++ b/code/AssetLib/COB/COBLoader.cpp
@@ -105,7 +105,7 @@ COBImporter::~COBImporter() {
 // Returns whether the class can handle the format of the given file.
 bool COBImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const char *tokens[] = { "Caligary" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/CSM/CSMLoader.cpp b/code/AssetLib/CSM/CSMLoader.cpp
index 8233bffbb..56c7c3afd 100644
--- a/code/AssetLib/CSM/CSMLoader.cpp
+++ b/code/AssetLib/CSM/CSMLoader.cpp
@@ -93,7 +93,7 @@ CSMImporter::~CSMImporter()
 bool CSMImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool /*checkSig*/) const
 {
     static const char* tokens[] = {"$Filename"};
-    return SearchFileHeaderForToken(pIOHandler,pFile,tokens,std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler,pFile,tokens,AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/Collada/ColladaLoader.cpp b/code/AssetLib/Collada/ColladaLoader.cpp
index a54b61c99..7870f4d70 100644
--- a/code/AssetLib/Collada/ColladaLoader.cpp
+++ b/code/AssetLib/Collada/ColladaLoader.cpp
@@ -125,7 +125,7 @@ bool ColladaLoader::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool
     }
 
     static const char *tokens[] = { "<collada" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/DXF/DXFLoader.cpp b/code/AssetLib/DXF/DXFLoader.cpp
index 9f9cb2897..29e7891ee 100644
--- a/code/AssetLib/DXF/DXFLoader.cpp
+++ b/code/AssetLib/DXF/DXFLoader.cpp
@@ -127,7 +127,7 @@ DXFImporter::~DXFImporter() {
 // Returns whether the class can handle the format of the given file.
 bool DXFImporter::CanRead( const std::string& filename, IOSystem* pIOHandler, bool /*checkSig*/ ) const {
     static const char *tokens[] = { "SECTION", "HEADER", "ENDSEC", "BLOCKS" };
-    return SearchFileHeaderForToken(pIOHandler, filename, tokens, std::size(tokens), 32);
+    return SearchFileHeaderForToken(pIOHandler, filename, tokens, AI_COUNT_OF(tokens), 32);
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/FBX/FBXImporter.cpp b/code/AssetLib/FBX/FBXImporter.cpp
index c80f87f12..673b572e5 100644
--- a/code/AssetLib/FBX/FBXImporter.cpp
+++ b/code/AssetLib/FBX/FBXImporter.cpp
@@ -103,7 +103,7 @@ FBXImporter::~FBXImporter() {
 bool FBXImporter::CanRead(const std::string & pFile, IOSystem * pIOHandler, bool /*checkSig*/) const {
 	// at least ASCII-FBX files usually have a 'FBX' somewhere in their head
 	static const char *tokens[] = { "fbx" };
-	return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+	return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/HMP/HMPLoader.cpp b/code/AssetLib/HMP/HMPLoader.cpp
index 1f71ec55e..6f9293fc7 100644
--- a/code/AssetLib/HMP/HMPLoader.cpp
+++ b/code/AssetLib/HMP/HMPLoader.cpp
@@ -89,7 +89,7 @@ bool HMPImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /
         AI_HMP_MAGIC_NUMBER_LE_5,
         AI_HMP_MAGIC_NUMBER_LE_7
     };
-    return CheckMagicToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return CheckMagicToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/IFC/IFCLoader.cpp b/code/AssetLib/IFC/IFCLoader.cpp
index 986898bf7..bf297e448 100644
--- a/code/AssetLib/IFC/IFCLoader.cpp
+++ b/code/AssetLib/IFC/IFCLoader.cpp
@@ -134,7 +134,7 @@ bool IFCImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /
     // it is only unambiguous as long as we don't support any further
     // file formats with STEP as their encoding.
     static const char *tokens[] = { "ISO-10303-21" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/Irr/IRRLoader.cpp b/code/AssetLib/Irr/IRRLoader.cpp
index e76d55615..501846dbe 100644
--- a/code/AssetLib/Irr/IRRLoader.cpp
+++ b/code/AssetLib/Irr/IRRLoader.cpp
@@ -96,7 +96,7 @@ IRRImporter::~IRRImporter() {
 // Returns whether the class can handle the format of the given file.
 bool IRRImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
 	static const char *tokens[] = { "irr_scene" };
-	return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+	return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/Irr/IRRMeshLoader.cpp b/code/AssetLib/Irr/IRRMeshLoader.cpp
index f991fa843..40410fbe9 100644
--- a/code/AssetLib/Irr/IRRMeshLoader.cpp
+++ b/code/AssetLib/Irr/IRRMeshLoader.cpp
@@ -92,7 +92,7 @@ bool IRRMeshImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bo
 	 * search for typical tokens.
 	 */
 	static const char *tokens[] = { "irrmesh" };
-	return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+	return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/LWO/LWOLoader.cpp b/code/AssetLib/LWO/LWOLoader.cpp
index 0477e7bd3..10dc0e508 100644
--- a/code/AssetLib/LWO/LWOLoader.cpp
+++ b/code/AssetLib/LWO/LWOLoader.cpp
@@ -111,7 +111,7 @@ bool LWOImporter::CanRead(const std::string &file, IOSystem *pIOHandler, bool /*
         AI_LWO_FOURCC_LWO2,
         AI_LWO_FOURCC_LXOB
     };
-    return CheckMagicToken(pIOHandler, file, tokens, std::size(tokens), 8);
+    return CheckMagicToken(pIOHandler, file, tokens, AI_COUNT_OF(tokens), 8);
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/LWS/LWSLoader.cpp b/code/AssetLib/LWS/LWSLoader.cpp
index e3e9aa0c4..69a956428 100644
--- a/code/AssetLib/LWS/LWSLoader.cpp
+++ b/code/AssetLib/LWS/LWSLoader.cpp
@@ -152,7 +152,7 @@ bool LWSImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /
         AI_MAKE_MAGIC("LWSC"),
         AI_MAKE_MAGIC("LWMO")
     };
-    return CheckMagicToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return CheckMagicToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/MD2/MD2Loader.cpp b/code/AssetLib/MD2/MD2Loader.cpp
index 77063be29..3e28c50f2 100644
--- a/code/AssetLib/MD2/MD2Loader.cpp
+++ b/code/AssetLib/MD2/MD2Loader.cpp
@@ -109,7 +109,7 @@ MD2Importer::~MD2Importer()
 bool MD2Importer::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool /*checkSig*/) const
 {
     static const uint32_t tokens[] = { AI_MD2_MAGIC_NUMBER_LE };
-    return CheckMagicToken(pIOHandler,pFile,tokens,std::size(tokens));
+    return CheckMagicToken(pIOHandler,pFile,tokens,AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/MD3/MD3Loader.cpp b/code/AssetLib/MD3/MD3Loader.cpp
index ec47790d5..02cbf493e 100644
--- a/code/AssetLib/MD3/MD3Loader.cpp
+++ b/code/AssetLib/MD3/MD3Loader.cpp
@@ -351,7 +351,7 @@ MD3Importer::~MD3Importer() {}
 // Returns whether the class can handle the format of the given file.
 bool MD3Importer::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const uint32_t tokens[] = { AI_MD3_MAGIC_NUMBER_LE };
-    return CheckMagicToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return CheckMagicToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/MD5/MD5Loader.cpp b/code/AssetLib/MD5/MD5Loader.cpp
index b2dbba94a..5ba60760c 100644
--- a/code/AssetLib/MD5/MD5Loader.cpp
+++ b/code/AssetLib/MD5/MD5Loader.cpp
@@ -102,7 +102,7 @@ MD5Importer::~MD5Importer() {
 // Returns whether the class can handle the format of the given file.
 bool MD5Importer::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const char *tokens[] = { "MD5Version" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/MDC/MDCLoader.cpp b/code/AssetLib/MDC/MDCLoader.cpp
index df56c3cf6..70d9605f2 100644
--- a/code/AssetLib/MDC/MDCLoader.cpp
+++ b/code/AssetLib/MDC/MDCLoader.cpp
@@ -112,7 +112,7 @@ MDCImporter::~MDCImporter() {
 // Returns whether the class can handle the format of the given file.
 bool MDCImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const uint32_t tokens[] = { AI_MDC_MAGIC_NUMBER_LE };
-    return CheckMagicToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return CheckMagicToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/MDL/MDLLoader.cpp b/code/AssetLib/MDL/MDLLoader.cpp
index 701d8add9..356365e7d 100644
--- a/code/AssetLib/MDL/MDLLoader.cpp
+++ b/code/AssetLib/MDL/MDLLoader.cpp
@@ -115,7 +115,7 @@ bool MDLImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /
         AI_MDL_MAGIC_NUMBER_LE_GS3,
         AI_MDL_MAGIC_NUMBER_LE
     };
-    return CheckMagicToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return CheckMagicToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/MMD/MMDImporter.cpp b/code/AssetLib/MMD/MMDImporter.cpp
index ab9e68177..410ae9e25 100644
--- a/code/AssetLib/MMD/MMDImporter.cpp
+++ b/code/AssetLib/MMD/MMDImporter.cpp
@@ -91,7 +91,7 @@ MMDImporter::~MMDImporter() {
 bool MMDImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler,
         bool /*checkSig*/) const {
     static const char *tokens[] = { "PMX " };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/MS3D/MS3DLoader.cpp b/code/AssetLib/MS3D/MS3DLoader.cpp
index 70be25fef..1977da502 100644
--- a/code/AssetLib/MS3D/MS3DLoader.cpp
+++ b/code/AssetLib/MS3D/MS3DLoader.cpp
@@ -93,7 +93,7 @@ MS3DImporter::~MS3DImporter()
 bool MS3DImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool /*checkSig*/) const
 {
     static const char* tokens[] = { "MS3D000000" };
-    return SearchFileHeaderForToken(pIOHandler,pFile,tokens,std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler,pFile,tokens,AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/NDO/NDOLoader.cpp b/code/AssetLib/NDO/NDOLoader.cpp
index 05d50af1d..fd0b29b59 100644
--- a/code/AssetLib/NDO/NDOLoader.cpp
+++ b/code/AssetLib/NDO/NDOLoader.cpp
@@ -85,7 +85,7 @@ NDOImporter::~NDOImporter()
 bool NDOImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool /*checkSig*/) const
 {
     static const char* tokens[] = {"nendo"};
-    return SearchFileHeaderForToken(pIOHandler,pFile,tokens,std::size(tokens),5);
+    return SearchFileHeaderForToken(pIOHandler,pFile,tokens,AI_COUNT_OF(tokens),5);
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/OFF/OFFLoader.cpp b/code/AssetLib/OFF/OFFLoader.cpp
index d1566b4f7..833d5bff2 100644
--- a/code/AssetLib/OFF/OFFLoader.cpp
+++ b/code/AssetLib/OFF/OFFLoader.cpp
@@ -88,7 +88,7 @@ OFFImporter::~OFFImporter()
 bool OFFImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool /*checkSig*/) const
 {
     static const char* tokens[] = { "off" };
-    return SearchFileHeaderForToken(pIOHandler,pFile,tokens,std::size(tokens),3);
+    return SearchFileHeaderForToken(pIOHandler,pFile,tokens,AI_COUNT_OF(tokens),3);
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/Ogre/OgreImporter.cpp b/code/AssetLib/Ogre/OgreImporter.cpp
index 36ee6edff..4f25ccc72 100644
--- a/code/AssetLib/Ogre/OgreImporter.cpp
+++ b/code/AssetLib/Ogre/OgreImporter.cpp
@@ -76,7 +76,7 @@ void OgreImporter::SetupProperties(const Importer *pImp) {
 bool OgreImporter::CanRead(const std::string &pFile, Assimp::IOSystem *pIOHandler, bool /*checkSig*/) const {
     if (EndsWith(pFile, ".mesh.xml", false)) {
         static const char *tokens[] = { "<mesh>" };
-        return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+        return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
     } else {
         /// @todo Read and validate first header chunk?
         return false;
diff --git a/code/AssetLib/OpenGEX/OpenGEXImporter.cpp b/code/AssetLib/OpenGEX/OpenGEXImporter.cpp
index 4ee9031d7..429a03ad8 100644
--- a/code/AssetLib/OpenGEX/OpenGEXImporter.cpp
+++ b/code/AssetLib/OpenGEX/OpenGEXImporter.cpp
@@ -283,7 +283,7 @@ OpenGEXImporter::~OpenGEXImporter() {
 //------------------------------------------------------------------------------------------------
 bool OpenGEXImporter::CanRead(const std::string &file, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const char *tokens[] = { "Metric", "GeometryNode", "VertexArray (attrib", "IndexArray" };
-    return SearchFileHeaderForToken(pIOHandler, file, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, file, tokens, AI_COUNT_OF(tokens));
 }
 
 //------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/Ply/PlyLoader.cpp b/code/AssetLib/Ply/PlyLoader.cpp
index d92ffacd1..86cf33703 100644
--- a/code/AssetLib/Ply/PlyLoader.cpp
+++ b/code/AssetLib/Ply/PlyLoader.cpp
@@ -102,7 +102,7 @@ PLYImporter::~PLYImporter() {
 // Returns whether the class can handle the format of the given file.
 bool PLYImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const char *tokens[] = { "ply" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/Q3D/Q3DLoader.cpp b/code/AssetLib/Q3D/Q3DLoader.cpp
index 74ff01ca0..9f41f190f 100644
--- a/code/AssetLib/Q3D/Q3DLoader.cpp
+++ b/code/AssetLib/Q3D/Q3DLoader.cpp
@@ -85,7 +85,7 @@ Q3DImporter::~Q3DImporter() {
 // Returns whether the class can handle the format of the given file.
 bool Q3DImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const char *tokens[] = { "quick3Do", "quick3Ds" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/STL/STLLoader.cpp b/code/AssetLib/STL/STLLoader.cpp
index 65cfc7830..68a2244f4 100644
--- a/code/AssetLib/STL/STLLoader.cpp
+++ b/code/AssetLib/STL/STLLoader.cpp
@@ -143,7 +143,7 @@ STLImporter::~STLImporter() {
 // Returns whether the class can handle the format of the given file.
 bool STLImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const char *tokens[] = { "STL", "solid" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/Terragen/TerragenLoader.cpp b/code/AssetLib/Terragen/TerragenLoader.cpp
index 16e5ac470..6308727f8 100644
--- a/code/AssetLib/Terragen/TerragenLoader.cpp
+++ b/code/AssetLib/Terragen/TerragenLoader.cpp
@@ -79,7 +79,7 @@ TerragenImporter::~TerragenImporter() {}
 // Returns whether the class can handle the format of the given file.
 bool TerragenImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
     static const char *tokens[] = { "terragen" };
-    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/X/XFileImporter.cpp b/code/AssetLib/X/XFileImporter.cpp
index 73cb1acda..a2a26824a 100644
--- a/code/AssetLib/X/XFileImporter.cpp
+++ b/code/AssetLib/X/XFileImporter.cpp
@@ -91,7 +91,7 @@ XFileImporter::~XFileImporter() {
 // Returns whether the class can handle the format of the given file.
 bool XFileImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool /*checkSig*/) const {
     static const uint32_t token[] = { AI_MAKE_MAGIC("xof ") };
-    return CheckMagicToken(pIOHandler,pFile,token,std::size(token));
+    return CheckMagicToken(pIOHandler,pFile,token,AI_COUNT_OF(token));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/AssetLib/XGL/XGLLoader.cpp b/code/AssetLib/XGL/XGLLoader.cpp
index 7e134a054..943791ef0 100644
--- a/code/AssetLib/XGL/XGLLoader.cpp
+++ b/code/AssetLib/XGL/XGLLoader.cpp
@@ -107,7 +107,7 @@ XGLImporter::~XGLImporter() {
 // Returns whether the class can handle the format of the given file.
 bool XGLImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
 	static const char *tokens[] = { "<world>", "<World>", "<WORLD>" };
-	return SearchFileHeaderForToken(pIOHandler, pFile, tokens, std::size(tokens));
+	return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/include/assimp/defs.h b/include/assimp/defs.h
index d61fd7901..dbaff24c1 100644
--- a/include/assimp/defs.h
+++ b/include/assimp/defs.h
@@ -322,4 +322,6 @@ static const ai_real ai_epsilon = (ai_real)0.00001;
 #define AI_DEBUG_INVALIDATE_PTR(x)
 #endif
 
+#define AI_COUNT_OF(X) (sizeof(X) / sizeof((X)[0]))
+
 #endif // !! AI_DEFINES_H_INC