Ticket #2998 (closed Feature Requests: fixed)
Make file_sink flushable
|Reported by:||Andrew Schweitzer <a.schweitzer.grps@…>||Owned by:||turkanis|
|Version:||Boost 1.38.0||Severity:||Not Applicable|
file_sink is hard to use as a debug log, since it does not flush.
For example, when used when pushed into a filtering_ostream with cout, if flush is not called, characters don't appear on console or in file in a timely fashion. If flush is called, the characters on the console appear but not those in the file, because file_sink does not implement Flushable concept, and doesn't flush.
file_sink fsink("out.txt"); tee_filter<file_sink> tee_fsink(fsink); fo.push(tee_fsink);
fo << "some text"; fo.flush();
is very useful for arbitrary chains of debug logs, but not currently usable.
The same issue applies to file, file_descriptor, and file_descriptor_sink.
If there is some reason these classes should not be modified to made flushable, then it seems easy to make flushable_* versions. Example of this attached, which was copied from file.hpp.
I also tried to add flushable_file_descriptor, by privately inheriting from file_descriptor, and adding a flush call which calls ::FlushFileBuffers? on handle()... but so far that doesn't seem to work, so not attaching.