Re: [PATCH] git-log: detect dup and fdopen failure

"Alex Riesen" [off-list ref] wrote:

On 6/27/07, Jim Meyering [off-list ref] wrote:

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"Alex Riesen" [off-list ref] wrote:

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Check if this works in some exotic but common
environments (like MacOSX, Cygwin or HP-UX).

What do you mean?
I know that dup and fdopen work in those environments.

Exactly as you described?

No, but why does that matter?

Are you sure fdopen on Cygwin
sets ENOMEM?

Are you suggesting not to use errno because
it won't contain useful information on Mingw32?

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It's ok, but for the fact that when dup fails, all you get
is the uninformative EINVAL from fdopen.

EBADF on Cygwin, 0 on Mingw32. Can't even imagine what msvc

EBADF is fine.  Setting errno to 0 upon error is a bug.
Don't cater to buggy systems.

(which actually isn't a developers tool, but very common) will return.

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(Yes, I do think that "duplicate standard output" is useless,
except for debugging. Exactly as strerror is, but that is shorter).

I like to include *something* in the diagnostic so that when someone
sees it and reports it developers have an easier time finding where it
comes from in the code.  Especially with something as unlikely (and hard
to reproduce) as this, that might be useful.

Then put file name and the line number in!

Surely you're playing devil's advocate, now...
If you go that route, you might as well use assert() for both conditions,
and we all know *that* is silly.