diff --git a/src/celcompat/fs.cpp b/src/celcompat/fs.cpp
index 10d378583..fedc7a686 100644
--- a/src/celcompat/fs.cpp
+++ b/src/celcompat/fs.cpp
@@ -611,8 +611,8 @@ path current_path()
 path current_path(std::error_code& ec)
 {
 #ifdef _WIN32
-    std::wstring p(MAX_PATH + 1, 0);
-    DWORD r = GetModuleFileNameW(nullptr, &p[0], MAX_PATH);
+    std::wstring buffer(MAX_PATH + 1, 0);
+    DWORD r = GetModuleFileNameW(nullptr, &buffer[0], MAX_PATH);
     if (r == 0)
     {
         ec = std::error_code(errno, std::system_category());
@@ -621,14 +621,14 @@ path current_path(std::error_code& ec)
     auto pos = buffer.find_last_of(L"\\/");
     return buffer.substr(0, pos);
 #else
-    std::string p(256, 0);
-    char *r = getcwd(&p[0], p.size());
+    std::string buffer(256, 0);
+    char *r = getcwd(&buffer[0], p.size());
     if (r == nullptr)
     {
         ec = std::error_code(errno, std::system_category());
         return path();
     }
-    return p;
+    return buffer;
 #endif
 }
 
diff --git a/src/celengine/render.cpp b/src/celengine/render.cpp
index e74becc09..21798ee86 100644
--- a/src/celengine/render.cpp
+++ b/src/celengine/render.cpp
@@ -86,8 +86,10 @@ std::ofstream hdrlog;
 #endif
 #ifdef _MSC_VER
 #include <malloc.h>
+#ifndef alloca
 #define alloca(s) _alloca(s)
 #endif
+#endif
 
 using namespace cmod;
 using namespace Eigen;
diff --git a/src/celengine/vertexobject.cpp b/src/celengine/vertexobject.cpp
index d9ae9c6fe..97b725335 100644
--- a/src/celengine/vertexobject.cpp
+++ b/src/celengine/vertexobject.cpp
@@ -131,7 +131,7 @@ void VertexObject::enableAttribArrays() noexcept
         auto  n = t.first;
         auto& p = t.second;
         glEnableVertexAttribArray(n);
-        glVertexAttribPointer(n, p.count, p.type, p.normalized, p.stride, (GLvoid*) p.offset);
+        glVertexAttribPointer(n, p.count, p.type, p.normalized, p.stride, (GLvoid*) (size_t) p.offset);
     }
 }