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Re: GCC's statement expression extension

To: Per Bothner <per at bothner dot com>
Subject: Re: GCC's statement expression extension
From: Jamie Lokier <egcs at tantalophile dot demon dot co dot uk>
Date: Sat, 29 Jul 2000 23:36:41 +0200
Cc: Mark Mitchell <mark at codesourcery dot com>, gcc at gcc dot gnu dot org
References: <12879.964370396@upchuck> <20000723095222D.mitchell@codesourcery.com> <20000726212440.A26183@cygnus.com> <20000726213803N.mitchell@codesourcery.com> <m2r98cde4h.fsf@bothner.com>

Per Bothner wrote:
> One use I've found for statement-expressions...

Another use I've found is when you want a local label in a big macro.
This is because the __label__ extension works only in statement
expressions.  So I've seen:

  #define foo(a1,a2) \
    do ({ __label__ l1, l2, l3; /* code... */; }) while(0)

Why doesn't __label__ work inside an ordinary statement block?

-- Jamie

References:
- Re: GCC's statement expression extension
  - From: Jeffrey A Law
- Re: GCC's statement expression extension
  - From: Mark Mitchell
- Re: GCC's statement expression extension
  - From: Richard Henderson
- Re: GCC's statement expression extension
  - From: Mark Mitchell
- Re: GCC's statement expression extension
  - From: Per Bothner

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