On Sun, Nov 24, 2019 at 05:13:15PM -0300, Guillermo wrote:
> Those are just two if statements 'sharing' a body for brevity. That
> deals with errors in the openat() and subsequent write() calls, for
> the file that controls cgroup membership. By displaying a message
> constructed in the same way in both cases, and then throwing an
> exception. *Shrug*
That particular piece of code
> if (0 > cgroup_procs_fd.get()) {
> procs_file_error: ...
> }
> if (0 > write(cgroup_procs_fd.get(), "0\n", 2)) goto procs_file_error;
seems equivalent to
> if (0 > cgroup_procs_fd.get() ||
> 0 > write(cgroup_procs_fd.get(), "0\n", 2)) {
> ...
> }
If the error handling branches that need reuse become more complex, the
following way can also be considered (cf. [1]):
> ...
> if (...) goto err;
> ...
> if (...) goto err;
> ...
> return;
> err:
> ...
> return;
Macros and/or helper functions (again cf. [1]; they can be factored into
a mini-library in nosh) can also be used to reduce boilerplate like
> const int error(errno);
> std::fprintf(stderr, ..., std::strerror(error));
> throw EXIT_FAILURE;
which can be easily observed after the attached patch is applied.
BTW, it seems that the value of errno is passed to std::strerror()
before anything can change the errno, which implies that `const int
error(errno);' can be left out and `errno' can be directly used as the
argument of std::strerror().
[1] <
https://gitea.com/CasperVector/decryst/src/branch/master/src/decr_lsa.c>.
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Received on Mon Nov 25 2019 - 02:52:02 UTC