Method CheckFile

util/system/filemap.cpp:155–162

    }

    void CheckFile() const {
        if (!File_.IsOpen()) {
            ythrow yexception() << "TMemoryMap: FILE '" << DbgName_ << "' is not open, " << LastSystemErrorText();
        }
        if (Length_ < 0) {
            ythrow yexception() << "'" << DbgName_ << "' is not a regular file";
        }
    }

    inline TImpl(FILE* f, EOpenMode om, TString dbgName)
        : File_(Duplicate(f))