Hello there.

Sorry to chime in after all the time, but I just wanted to clear this one up:

On 11 Apr 2014, at 16:10, Alexander Burger <a...@software-lab.de> wrote:
> [...] Still, I can't understand why clang doesn't support variable-sized
> structures.

We discussed about that about two years ago, when I got interested in picoLisp 
and posted here a warning about Apple going to ditch GCC for Clang.

Dynamically-sized arrays in structures are a long-time GCC extension, but C99 
explicitly forbids them (cfr. p6.7.2.1 in C99 standard document). The Clang 
compiler manual has more to say about it (quoting):

<<clang does not support the gcc extension that allows variable-length arrays 
in structures. This is for a few reasons: one, it is tricky to implement, two, 
the extension is completely undocumented, and three, the extension appears to 
be rarely used. Note that clang does support flexible array members (arrays 
with a zero or unspecified size at the end of a structure).>> (from 

Luckily, it is possible to translate variable-sized fields in picoLisp/32bit 
source code to flexible array members. I wrote a patch for picoLisp (32bit) two 
years ago but since then I lost interested in the project and I'm not sure it's 
still applicable to the current source.

Happy hacking!

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