> It would appear that synchronization and buffering are mutually exclusive
For the standard streams, C specifies:
At program startup, three text streams are predefined and need not be opened explicitly — standard input (for reading conventional input), standard output (for writing conventional output), and standard error (for writing diagnostic output). As initially opened, the standard error stream is not fully buffered; the standard input and standard output streams are fully buffered if and only if the stream can be determined not to refer to an interactive device.
It may be possible to change the buffering of the standard C streams with std::setbuf / std::setvbuf; however, the C standard states that buffering behaviour is implementation defined. C99, re. buffering:
Support for these characteristics is implementation-defined, and may be affected via the setbuf and setvbuf functions.