Return value of std.process.system
art.08.09 at gmail.com
Sat Feb 25 11:14:05 PST 2012
On 02/25/12 19:39, H. S. Teoh wrote:
> What should the return value of std.process.system be?
> I'm looking at issue 6926, and upon investigation found that
> std.process.system always returns WEXITSTATUS(status) regardless of the
> value of WIFEXITED(status). This means that if the child process exits
> with a signal or dumps core, it may still return 0, whereas one would
> expect it should return some non-zero value.
> The comments in the code indicate that WEXITSTATUS(status) is used to
> provide maximum convenience (no need to use another macro/translation
> scheme to get at the return code, uniformity with Windows, etc.), but
> the current behaviour is obviously broken.
> There's currently a check for status==-1, in which case -1 is returned.
> I think we should extend this so that if WIFEXITED(status) is false,
> then -1 should be returned. What do y'all think?
> Furthermore, the version(Posix) block doesn't use any of the C macros at
> all, but has (status & 0xff00)>>>8, which equals WEXITSTATUS(status) on
> Linux systems. Do we know for sure that this is correct across *all*
> Unixen? AFAIK, the Posix spec leaves the details of WEXITSTATUS up to
> implementation. If so, the current implementation is technically broken.
> What's the best way to fix this? I'm inclined to move the implementation
> of this function into C, at least for version(Posix), so that we can get
> at the C macros and be sure that the result will be correct.
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