diff --git a/solvespace.h b/solvespace.h
index cb2b337..f8eb617 100644
--- a/solvespace.h
+++ b/solvespace.h
@@ -167,11 +167,11 @@ void CnfThawString(char *str, int maxLen, const char *name);
 DWORD CnfThawDWORD(DWORD v, const char *name);
 float CnfThawFloat(float v, const char *name);
 
-void *AllocTemporary(int n);
+void *AllocTemporary(size_t n);
 void FreeTemporary(void *p);
 void FreeAllTemporary(void);
-void *MemRealloc(void *p, int n);
-void *MemAlloc(int n);
+void *MemRealloc(void *p, size_t n);
+void *MemAlloc(size_t n);
 void MemFree(void *p);
 void InitHeaps(void);
 void vl(void); // debug function to validate heaps
diff --git a/win32/w32util.cpp b/win32/w32util.cpp
index 795fd80..894c941 100644
--- a/win32/w32util.cpp
+++ b/win32/w32util.cpp
@@ -39,7 +39,7 @@ void GetAbsoluteFilename(char *file)
 // to be sloppy with our memory management, and just free everything at once
 // at the end.
 //-----------------------------------------------------------------------------
-void *AllocTemporary(int n)
+void *AllocTemporary(size_t n)
 {
     void *v = HeapAlloc(TempHeap, HEAP_NO_SERIALIZE | HEAP_ZERO_MEMORY, n);
     if(!v) oops();
@@ -57,7 +57,7 @@ void FreeAllTemporary(void)
     vl();
 }
 
-void *MemRealloc(void *p, int n) {
+void *MemRealloc(void *p, size_t n) {
     if(!p) {
         return MemAlloc(n);
     }
@@ -66,7 +66,7 @@ void *MemRealloc(void *p, int n) {
     if(!p) oops();
     return p;
 }
-void *MemAlloc(int n) {
+void *MemAlloc(size_t n) {
     void *p = HeapAlloc(PermHeap, HEAP_NO_SERIALIZE | HEAP_ZERO_MEMORY, n);
     if(!p) oops();
     return p;