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Re: Why do Fdefvar not protect its argument and temporaries with GCPRO?
From: |
Andreas Schwab |
Subject: |
Re: Why do Fdefvar not protect its argument and temporaries with GCPRO? |
Date: |
Wed, 19 Nov 2014 10:44:48 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
Lee Duhem <address@hidden> writes:
> In the definition of `Fdefvar`, it calls `eval_sub`, and its temporary
> variable `tail` is used after that call. So why do `Fdefvar` not protect
> `tail` and other temporaries from GC with GCPRO? As other functions in
> `src/eval.c` did.
I think a few of them do too much GCPRO, since arguments of lisp
functions are protected by the caller (and conses are not relocated).
In the initial version of Fdefvar no intermediate values were stored in
variables, instead they were recomputed by calling Fcdr/Fcar on the
function argument, which is ok protection-wise.
> Is this a bug?
In this case, I think it is.
Andreas.
--
Andreas Schwab, SUSE Labs, address@hidden
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