ReportError doesn't flush stderr before exiting, swallowing error output about gflags HOT 6 CLOSED

stderr is not buffered by default on any system that I know.  fflush(stderr) 
should be unnecessary.  Are you doing something unusual in your setup, perhaps? 
 Or does cygwin?  I don't see any mention of it on a quick web search.

Anyway, no harm in adding it, I suppose.  Feel free to draw up a patch.

I've had a bit of a dig, and it turns out that the rxvt terminal emulator that 
ships with Cygwin buffers stderr. The reason for this seems to be that rxvt 
needs a pty I/O layer that simply doesn't exist on Windows, so it's emulated 
with pipes, which introduces the buffering. Given there's no harm adding it, 
I'll draw up a patch to work around this. Thanks.

I just released a new version of gflags, and decided not to fix this for that.  
stderr is standardized to flush, and I think it's just confusing to add code to 
flush it anyway.  Presumably cygwin/rxvt users are used to dealing with 
problems of this sort?

You're right it's just one line of code, and easy to fix, so I can still be 
convinced to do it. :-)  I'm leaving the bug open.

} stderr is standardized to flush, and I think it's just confusing to add code 
to flush it anyway.

Wouldn't it be clear enough if you simply comment the code properly?

// flush stderr before exiting as at least cygwin/rxvt buffers stderr
fflush (stderr);

This would make your library more reliable and such commented line of code 
couldn't be confusing to anyone who is digging into the code of it.

OK, I'm convinced. :-)  It'll be in the next release.

This should be fixed in gflags 1.7, just released