diff --git a/dlls/msvcirt/msvcirt.c b/dlls/msvcirt/msvcirt.c
index 0979673e1e..960cd90727 100644
--- a/dlls/msvcirt/msvcirt.c
+++ b/dlls/msvcirt/msvcirt.c
@@ -696,13 +696,21 @@ void * __thiscall MSVCIRT_ios_sl_void(class_ios * _this)
 
 /******************************************************************
  *		 ??0ostrstream@@QAE@XZ (MSVCRTI.@)
- *        class ostream & __thiscall ostrstream::ostrstream<<(void)
  */
-DEFINE_THISCALL_WRAPPER(MSVCIRT_ostrstream_sl_void,4)
-void * __thiscall MSVCIRT_ostrstream_sl_void(class_ostream * _this)
+DEFINE_THISCALL_WRAPPER(MSVCIRT_ostrstream_ctor,8)
+void * __thiscall MSVCIRT_ostrstream_ctor(class_ostream *this, BOOL virt_init)
 {
-   FIXME("(%p) stub\n", _this);
-   return _this;
+   FIXME("(%p %x) stub\n", this, virt_init);
+   return this;
+}
+
+/******************************************************************
+ *		 ??1ostrstream@@UAE@XZ (MSVCRTI.@)
+ */
+DEFINE_THISCALL_WRAPPER(MSVCIRT_ostrstream_dtor,4)
+void __thiscall MSVCIRT_ostrstream_dtor(class_ios *base)
+{
+    FIXME("(%p) stub\n", base);
 }
 
 /******************************************************************
diff --git a/dlls/msvcirt/msvcirt.spec b/dlls/msvcirt/msvcirt.spec
index 0c9e520900..36d42eeded 100644
--- a/dlls/msvcirt/msvcirt.spec
+++ b/dlls/msvcirt/msvcirt.spec
@@ -96,8 +96,8 @@
 @ stub -arch=win64 ??0ostrstream@@QEAA@AEBV0@@Z
 @ stub -arch=win32 ??0ostrstream@@QAE@PADHH@Z  # __thiscall ostrstream::ostrstream(char *,int,int)
 @ stub -arch=win64 ??0ostrstream@@QEAA@PEADHH@Z
-@ thiscall -arch=win32 ??0ostrstream@@QAE@XZ(ptr) MSVCIRT_ostrstream_sl_void  # __thiscall ostrstream::ostrstream(void)
-@ cdecl -arch=win64 ??0ostrstream@@QEAA@XZ(ptr) MSVCIRT_ostrstream_sl_void
+@ thiscall -arch=win32 ??0ostrstream@@QAE@XZ(ptr long) MSVCIRT_ostrstream_ctor
+@ cdecl -arch=win64 ??0ostrstream@@QEAA@XZ(ptr long) MSVCIRT_ostrstream_ctor
 @ stub -arch=win32 ??0stdiobuf@@QAE@ABV0@@Z  # __thiscall stdiobuf::stdiobuf(class stdiobuf const &)
 @ stub -arch=win64 ??0stdiobuf@@QEAA@AEBV0@@Z
 @ stub -arch=win32 ??0stdiobuf@@QAE@PAU_iobuf@@@Z  # __thiscall stdiobuf::stdiobuf(struct _iobuf *)
@@ -158,8 +158,8 @@
 @ stub -arch=win64 ??1ostream@@UEAA@XZ
 @ stub -arch=win32 ??1ostream_withassign@@UAE@XZ  # virtual __thiscall ostream_withassign::~ostream_withassign(void)
 @ stub -arch=win64 ??1ostream_withassign@@UEAA@XZ
-@ thiscall -arch=win32 ??1ostrstream@@UAE@XZ(ptr) MSVCIRT_ostrstream_sl_void # virtual __thiscall ostrstream::~ostrstream(void)
-@ cdecl -arch=win64 ??1ostrstream@@UEAA@XZ(ptr) MSVCIRT_ostrstream_sl_void
+@ thiscall -arch=win32 ??1ostrstream@@UAE@XZ(ptr) MSVCIRT_ostrstream_dtor
+@ cdecl -arch=win64 ??1ostrstream@@UEAA@XZ(ptr) MSVCIRT_ostrstream_dtor
 @ stub -arch=win32 ??1stdiobuf@@UAE@XZ  # virtual __thiscall stdiobuf::~stdiobuf(void)
 @ stub -arch=win64 ??1stdiobuf@@UEAA@XZ
 @ stub -arch=win32 ??1stdiostream@@UAE@XZ  # virtual __thiscall stdiostream::~stdiostream(void)
diff --git a/dlls/msvcrt20/msvcrt20.spec b/dlls/msvcrt20/msvcrt20.spec
index c7b28bd081..fe1d80cb98 100644
--- a/dlls/msvcrt20/msvcrt20.spec
+++ b/dlls/msvcrt20/msvcrt20.spec
@@ -86,8 +86,8 @@
 @ stub -arch=win64 ??0ostrstream@@QEAA@AEBV0@@Z
 @ stub -arch=win32 ??0ostrstream@@QAE@PADHH@Z
 @ stub -arch=win64 ??0ostrstream@@QEAA@PEADHH@Z
-@ thiscall -arch=win32 ??0ostrstream@@QAE@XZ(ptr) msvcirt.??0ostrstream@@QAE@XZ
-@ cdecl -arch=win64 ??0ostrstream@@QEAA@XZ(ptr) msvcirt.??0ostrstream@@QEAA@XZ
+@ thiscall -arch=win32 ??0ostrstream@@QAE@XZ(ptr long) msvcirt.??0ostrstream@@QAE@XZ
+@ cdecl -arch=win64 ??0ostrstream@@QEAA@XZ(ptr long) msvcirt.??0ostrstream@@QEAA@XZ
 @ stub -arch=win32 ??0stdiobuf@@QAE@ABV0@@Z
 @ stub -arch=win64 ??0stdiobuf@@QEAA@AEBV0@@Z
 @ stub -arch=win32 ??0stdiobuf@@QAE@PAU_iobuf@@@Z
diff --git a/dlls/msvcrt40/msvcrt40.spec b/dlls/msvcrt40/msvcrt40.spec
index 49df71c399..6fa30788b3 100644
--- a/dlls/msvcrt40/msvcrt40.spec
+++ b/dlls/msvcrt40/msvcrt40.spec
@@ -108,8 +108,8 @@
 @ stub -arch=win64 ??0ostrstream@@QEAA@AEBV0@@Z
 @ stub -arch=win32 ??0ostrstream@@QAE@PADHH@Z
 @ stub -arch=win64 ??0ostrstream@@QEAA@PEADHH@Z
-@ thiscall -arch=win32 ??0ostrstream@@QAE@XZ(ptr) msvcirt.??0ostrstream@@QAE@XZ
-@ cdecl -arch=win64 ??0ostrstream@@QEAA@XZ(ptr) msvcirt.??0ostrstream@@QEAA@XZ
+@ thiscall -arch=win32 ??0ostrstream@@QAE@XZ(ptr long) msvcirt.??0ostrstream@@QAE@XZ
+@ cdecl -arch=win64 ??0ostrstream@@QEAA@XZ(ptr long) msvcirt.??0ostrstream@@QEAA@XZ
 @ stub -arch=win32 ??0stdiobuf@@QAE@ABV0@@Z
 @ stub -arch=win64 ??0stdiobuf@@QEAA@AEBV0@@Z
 @ stub -arch=win32 ??0stdiobuf@@QAE@PAU_iobuf@@@Z