C++ TFileTransport ignores return code from ftruncate

src/thrift/transport/TFileTransport.cpp: In member function 'void apache::thrift::transport::TFileTransport::writerThread()':
src/thrift/transport/TFileTransport.cpp:316:34: warning: ignoring return value of 'int ftruncate(int, __off_t)', declared with attribute warn_unused_result [-Wunused-result]
    THRIFT_FTRUNCATE(fd_, offset_);