iostreams file_descriptor::write fails under Win32

[nobody]

in 1.33.1, file_descriptor::write(), append mode implemented as

#ifdef BOOST_IOSTREAMS_WINDOWS
    if (pimpl_->flags_ & impl::has_handle) {
        if (pimpl_->flags_ & impl::append) {
            ::SetFilePointer(pimpl_->handle_, 0, NULL, FILE_END);
            if (::GetLastError() != NO_ERROR)
                throw detail::bad_seek();


it is common mistake to call GetLastError() without checking function return value first. MSDN has special note for SetFilePointer():

"Note  If the function returns a value other than INVALID_SET_FILE_POINTER, the call to SetFilePointer has succeeded. You do not need to call GetLastError."

So, file_descriptor::write() fails, if there is old uncleaned "last" error

Regards,

valeri.antonov@gmail.com

[gmsb]

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This is the same issue as in the comment on patches #1452698.

How can we speed up when this and other Boost.Iostreams patches are applied?

[Frank Birbacher]

Bug noted and addressed in [38879]. Still needs approval of maintainer.

[anonymous]

Is this a duplicate of ticket #699

[Jonathan Turkanis]

this is not a duplicate of #699; #699 deals with mapped_file, not file_descriptor

[Jonathan Turkanis]

Fixed in [42266]