> On Jan. 9, 2016, 12:42 a.m., Joris Van Remoortere wrote: > > 3rdparty/libprocess/3rdparty/stout/include/stout/internal/windows/dirent.hpp, > > line 204 > > <https://reviews.apache.org/r/39019/diff/10/?file=1175210#file1175210line204> > > > > why assert vs. false with errno? > > Alex Clemmer wrote: > Actually, I changed my mind about the stuff I wrote about `assert` above, > which I clicked "publish" on a couple minutes ago. > > I tend to think of `errno` (loosely) as communicating an error performing > some action at an API level. For example, if you pass a nonexistant directory > to `opendir` then `errno` will be populated to indicate that. But, in this > case, if the `DIR*` passed to `_openDirStream` is `NULL`, because > `_openDirStream` does not know how to communicate to the caller of `opendir` > what went wrong. Did we run out of memory, which caused the `DIR*` to be > `NULL`? Did we overwrite something somewhere? We don't know. This is in > contrast to the case where we try to find the first file in the directory > stream. In this case, `_openDirStream` is the _only_ function that can > populate `errno`, because it is the only function that knows what went wrong! > Therefore, we populate `errno` in that case, and only that case. > > So, in this case, I think it's better to just `assert` rather than set > `errno`: because, if even if we do set `errno` to indicate that `NULL` is > unacceptable, the user won't know what the problem is, and can't change their > input accordingly. In contrast, when you `assert`, it becomes very obvious > that there is a bug in internal code, which is infinitely preferable IMHO. > > What do you think?
Following up, we've agreed that it's acceptable to do this in an internal API, but leading underscores is not a "good enough" solution. So, in this next revision, we will move these internal APIs to the `internal` namespace. - Alex ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/39019/#review113576 ----------------------------------------------------------- On Jan. 11, 2016, 10:03 p.m., Alex Clemmer wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/39019/ > ----------------------------------------------------------- > > (Updated Jan. 11, 2016, 10:03 p.m.) > > > Review request for mesos, Alex Naparu, Daniel Pravat, Artem Harutyunyan, > Joris Van Remoortere, and Joseph Wu. > > > Bugs: MESOS-3441 > https://issues.apache.org/jira/browse/MESOS-3441 > > > Repository: mesos > > > Description > ------- > > Windows: Added dirent compat code for non-Unix systems. > > > Diffs > ----- > > 3rdparty/libprocess/3rdparty/stout/include/Makefile.am > b2dea9b93adfa3ea0415a0b5c81a369dd29b6cfe > > 3rdparty/libprocess/3rdparty/stout/include/stout/internal/windows/dirent.hpp > PRE-CREATION > 3rdparty/libprocess/3rdparty/stout/include/stout/windows.hpp > d46e262e0fd1c2de36f3bf19d8bd693c23bf58cd > > Diff: https://reviews.apache.org/r/39019/diff/ > > > Testing > ------- > > `make check` from autotools on Ubuntu 15. > `make check` from CMake on OS X 10.10. > Ran `check` project in VS on Windows 10. > > > Thanks, > > Alex Clemmer > >
