diff --git a/core/src/fxcrt/fx_basic_wstring.cpp b/core/src/fxcrt/fx_basic_wstring.cpp
index e7f8c01..c097e1f 100644
--- a/core/src/fxcrt/fx_basic_wstring.cpp
+++ b/core/src/fxcrt/fx_basic_wstring.cpp
@@ -32,7 +32,7 @@
   int usableLen = (totalSize - overhead) / sizeof(FX_WCHAR);
   FXSYS_assert(usableLen >= nLen);
 
-  void* pData = FX_Alloc(uint8_t, iSize.ValueOrDie());
+  void* pData = FX_Alloc(uint8_t, totalSize);
   return new (pData) StringData(nLen, usableLen);
 }
 CFX_WideString::~CFX_WideString() {