'_FPOSOFF' has been deprecated, error C3861: '_FPOSOFF': identifier not found

[FrankXie05]

I am the maintainer of vcpkg and we found above error when we test this port in an internal version of Visual Studio.

This error due to _FPOSOFF' has been completely deprecated after the standard MSVC-PR-132953 .

For fixing this issue: we think bellow code

OpenSceneGraph/src/osgPlugins/osga/OSGA_Archive.cpp

Line 80 in 2e4ae2e

std::streamoff offset = pos.operator std::streamoff( ) - _FPOSOFF( position );

could be change to

std::streamoff offset = 0;

Reason:
When pos.operator std::streamoff() is called, the std::streampos object pos is actually converted to the std::streamoff type to obtain its offset in the stream. And _FPOSOFF(position) is to get the offset of the fpos_t object position in the stream.

In this code, the calculate the offset of pos relative to position, but because the definition of _FPOSOFF is no longer available, and since the result of _FPOSOFF(position) is the same as pos.operator std::streamoff().
Related PR:
microsoft/STL#4606
microsoft/vcpkg#38666

If you have other solotions, please ping me. I will apply it to vcpkg for this issue. :)

[robertosfield]

I'm not the author of this particular workaround for prior issues with Win32:

#if ((defined(_YVALS) && !defined(IBMCPP)) || defined(_CPPLIB_VER)) &&
!defined(__SGI_STL_PORT) && !defined(_STLPORT_VERSION)
&& !defined(QNX)

...

#else

And just use the path used by all platforms:

// do the old school streampos <-> streamoff casts
inline std::streampos STREAM_POS( const OSGA_Archive::pos_type pos )
{
return std::streampos( pos );
}

inline OSGA_Archive::pos_type ARCHIVE_POS( const std::streampos & pos )
{
return OSGA_Archive::pos_type( pos );
}