diff --git a/doomsday/sdk/libcore/include/de/libcore.h b/doomsday/sdk/libcore/include/de/libcore.h
index 0ec6710869..83ac7c67e0 100644
--- a/doomsday/sdk/libcore/include/de/libcore.h
+++ b/doomsday/sdk/libcore/include/de/libcore.h
@@ -590,7 +590,7 @@ typedef qint64  dint64;     ///< 64-bit signed integer.
 typedef quint64 duint64;    ///< 64-bit unsigned integer.
 typedef float   dfloat;     ///< 32-bit floating point number.
 typedef double  ddouble;    ///< 64-bit floating point number.
-typedef quint64 dsize;
+typedef size_t  dsize;
 
 // Pointer-integer conversion (used for legacy code).
 #ifdef DENG2_64BIT
@@ -629,12 +629,7 @@ typedef unsigned char   dbyte;
 typedef unsigned int    duint;  // 32-bit
 typedef float           dfloat;
 typedef double          ddouble;
-
-#ifdef DENG2_64BIT
-typedef uint64_t        dsize;  // 64-bit size
-#else
-typedef unsigned int    dsize;  // 32-bit size
-#endif
+typedef size_t          dsize;
 
 #endif // !__cplusplus