diff --git a/RecastDemo/Source/InputGeom.cpp b/RecastDemo/Source/InputGeom.cpp
index a0ec2c2..3d08855 100644
--- a/RecastDemo/Source/InputGeom.cpp
+++ b/RecastDemo/Source/InputGeom.cpp
@@ -166,10 +166,26 @@ bool InputGeom::loadGeomSet(rcContext* ctx, const std::string& filepath)
 	char* buf = 0;
 	FILE* fp = fopen(filepath.c_str(), "rb");
 	if (!fp)
+	{
 		return false;
-	fseek(fp, 0, SEEK_END);
-	int bufSize = ftell(fp);
-	fseek(fp, 0, SEEK_SET);
+	}
+	if (fseek(fp, 0, SEEK_END) != 0)
+	{
+		fclose(fp);
+		return false;
+	}
+
+	long bufSize = ftell(fp);
+	if (bufSize < 0)
+	{
+		fclose(fp);
+		return false;
+	}
+	if (fseek(fp, 0, SEEK_SET) != 0)
+	{
+		fclose(fp);
+		return false;
+	}
 	buf = new char[bufSize];
 	if (!buf)
 	{
diff --git a/RecastDemo/Source/MeshLoaderObj.cpp b/RecastDemo/Source/MeshLoaderObj.cpp
index 66f4d7f..8b44127 100644
--- a/RecastDemo/Source/MeshLoaderObj.cpp
+++ b/RecastDemo/Source/MeshLoaderObj.cpp
@@ -141,9 +141,22 @@ bool rcMeshLoaderObj::load(const std::string& filename)
 	FILE* fp = fopen(filename.c_str(), "rb");
 	if (!fp)
 		return false;
-	fseek(fp, 0, SEEK_END);
-	int bufSize = ftell(fp);
-	fseek(fp, 0, SEEK_SET);
+	if (fseek(fp, 0, SEEK_END) != 0)
+	{
+		fclose(fp);
+		return false;
+	}
+	long bufSize = ftell(fp);
+	if (bufSize < 0)
+	{
+		fclose(fp);
+		return false;
+	}
+	if (fseek(fp, 0, SEEK_SET) != 0)
+	{
+		fclose(fp);
+		return false;
+	}
 	buf = new char[bufSize];
 	if (!buf)
 	{
diff --git a/RecastDemo/Source/TestCase.cpp b/RecastDemo/Source/TestCase.cpp
index 7c447a3..aecf9a8 100644
--- a/RecastDemo/Source/TestCase.cpp
+++ b/RecastDemo/Source/TestCase.cpp
@@ -102,9 +102,22 @@ bool TestCase::load(const std::string& filePath)
 	FILE* fp = fopen(filePath.c_str(), "rb");
 	if (!fp)
 		return false;
-	fseek(fp, 0, SEEK_END);
-	int bufSize = ftell(fp);
-	fseek(fp, 0, SEEK_SET);
+	if (fseek(fp, 0, SEEK_END) != 0)
+	{
+		fclose(fp);
+		return false;
+	}
+	long bufSize = ftell(fp);
+	if (bufSize < 0)
+	{
+		fclose(fp);
+		return false;
+	}
+	if (fseek(fp, 0, SEEK_SET) != 0)
+	{
+		fclose(fp);
+		return false;
+	}
 	buf = new char[bufSize];
 	if (!buf)
 	{
diff --git a/RecastDemo/Source/imguiRenderGL.cpp b/RecastDemo/Source/imguiRenderGL.cpp
index a595964..9f05375 100644
--- a/RecastDemo/Source/imguiRenderGL.cpp
+++ b/RecastDemo/Source/imguiRenderGL.cpp
@@ -247,9 +247,22 @@ bool imguiRenderGLInit(const char* fontpath)
 	// Load font.
 	FILE* fp = fopen(fontpath, "rb");
 	if (!fp) return false;
-	fseek(fp, 0, SEEK_END);
-	size_t size = ftell(fp);
-	fseek(fp, 0, SEEK_SET);
+	if (fseek(fp, 0, SEEK_END) != 0)
+	{
+		fclose(fp);
+		return false;
+	}
+	long size = ftell(fp);
+	if (size < 0)
+	{
+		fclose(fp);
+		return false;
+	}
+	if (fseek(fp, 0, SEEK_SET) != 0)
+	{
+		fclose(fp);
+		return false;
+	}
 	
 	unsigned char* ttfBuffer = (unsigned char*)malloc(size); 
 	if (!ttfBuffer)
@@ -260,7 +273,7 @@ bool imguiRenderGLInit(const char* fontpath)
 	
 	size_t readLen = fread(ttfBuffer, 1, size, fp);
 	fclose(fp);
-	if (readLen != size)
+	if (readLen != static_cast<size_t>(size))
 	{
 		free(ttfBuffer);
 		return false;