FILE's _file can only hold a short

Ian Lepore freebsd at
Thu Nov 1 14:40:35 UTC 2012

On Wed, 2012-10-31 at 11:12 -0700, mdf at wrote:
> I seem to recall a thread earlier on this limitation, but looking at
> actual libc/stdio sources, the 4 year old check for open(2)'s fd being
> less than SHRT_MAX is still there.  I thought I saw a patch to change
> this to an int, but it's not in the tree.  Was this in a PR or a
> mailing list thread or am I just imagining things?
> We've run into this limitation at work, where some processes have
> around 32k open file descriptors and then try to use the libc FILE
> interface.  Since we control ABI we can just change this to int, but I
> had been hoping there was a FreeBSD revision we could pull instead of
> having another diff.

FWIW, I also remember some discussion recently (this year) on some
mailing list about this, but I can't find it now.  I thought it was
somehow related to in-lib versus external uses of the funopen()
function, but I may be conflating two unrelated discusssions in my head.

-- Ian

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