From: David Gibson <david@gibson.dropbear.id.au>
To: ccan@lists.ozlabs.org
Subject: Re: dgraph, tlist, tcon: MSVC error due to array of flexible structs
Date: Tue, 1 Aug 2017 15:22:05 +1000 [thread overview]
Message-ID: <20170801052205.GO2652@umbus.fritz.box> (raw)
In-Reply-To: <20160923043116.ytrxrm7dsgusdrif@kevinolos>
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On Thu, Sep 22, 2016 at 10:31:16PM -0600, Kevin Locke wrote:
1;4803;0c> Hi all,
>
> Building dgraph using Microsoft Visual C++ produces the following
> error:
>
> dgraph.h(25): error C2233: 'edge': arrays of objects containing
> zero-size arrays are illegal
>
> The issue is that MSVC supports flexible array members, but does not
> support arrays of structs with flexible array members. My
> understanding is that such support is not required by C99 or C11, but
> I don't know whether such support is common beyond Clang/GCC.
>
> Is there any interest in supporting such compilers? If so, I can see
> a few potential fixes:
>
> 1. Change TCON to use flexible array members only when the compiler
> supports arrays of structs with flexible array members. This is an
> easy fix, but wastes space for every TCON/TLIST usage on such
> compilers.
>
> 2. Have TCON (and TLIST) provide an alternative macro which uses
> flexible array members only when supported in arrays, and use that in
> dgraph. It would increase the API and duplicate a bit of code, but
> would only waste space when TCON/TLIST are placed in arrays.
>
> 2. Replace the 2-element edge array in struct dgraph_node with
> separate fields edge_from and edge_to. This complicates the logic a
> bit, since it is no longer symmetric with dgraph_edge. It would also
> be an incompatible API change.
>
> 3. Change TLIST to use TCON_WRAP? I don't understand TLIST/TCON well
> enough to know if this is really an option. Hopefully an expert can
> weigh in here.
I've now done this for tlist and several other modules, we should have
a much better chance of compiling on windows.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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next prev parent reply other threads:[~2017-08-01 5:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-23 4:31 dgraph, tlist, tcon: MSVC error due to array of flexible structs Kevin Locke
2016-09-27 4:45 ` David Gibson
2016-09-28 2:10 ` Rusty Russell
2016-09-28 3:12 ` David Gibson
2017-08-01 5:22 ` David Gibson [this message]
2017-08-02 5:38 ` Kevin Locke
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