What causes "error C2856: #pragma hdrstop cannot be inside an #if block" in VS C++?

There was a program what I could compile under 2008 for a while. Note I can compile the program using cl and in Ultimate++ IDE. It is a fairly large program , so I am not going to post it here. I cannot compile it in Studio.

The error is

1>c:\program files\microsoft visual studio 9.0\vc\include\xstring(1735)
: error C2856: #pragma hdrstop cannot be inside an #if block

which seems to be idiotic as there is no hdrstop in there.

Precompiled headers are turned off.

This is what is there:

            if (_Mysize < _Off)
                _String_base::_Xran();  // _Off off end
            if (_Mysize - _Off < _Count)
                _Count = _Mysize - _Off;
            _Traits_helper::copy_s<_Traits>(_Dest, _Dest_size, _Myptr() + _Off, _Count);
            return (_Co开发者_运维百科unt);
            }

        void __CLR_OR_THIS_CALL swap(_Myt& _Right)
            {   // exchange contents with _Right <<<<<<<<----------this is the line 
            if (this == &_Right)
                ;   // same object, do nothing
            else if (_Mybase::_Alval == _Right._Alval)
                {   // same allocator, swap control information

Thanks.

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I found this out. It caused by precompiled headers, yes but there is no need to turn this off.

It happens when a top level #include "headertobeprecompiled.h" is inside an #if #endif block. If one can move it outside that the error message disappears.

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Wild guess.

The precompiled headers are switched off for the project? Are they switched off for every single source file in the project (cause individual file settings overwrite whole-project settings).

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Because Visual C++ invokes cl (which works fine) and you obviously have messed up headers, the first thing I'd check are include paths. Post them here.

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I have experienced the exact same problem and was also puzzled since I don't have any hdrstop pragmas in my code, either. However, I compile from a script (not an IDE) and when I omit the compiler option /Yc (create PCH) the error disappears.