From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark Mitchell <mark@codesourcery.com>
To: egcs@tantalophile.demon.co.uk
Cc: mrs@windriver.com, gcc@gcc.gnu.org, per@bothner.com
Subject: Re: GCC's statement expression extension
Date: Fri, 04 Aug 2000 09:04:00 -0000
Message-id: <20000804090346I.mitchell@codesourcery.com>
References: <200008032132.OAA10481@kankakee.wrs.com> <20000804133525.A8926@pcep-jamie.cern.ch>
X-SW-Source: 2000-08/msg00111.html

>>>>> "Jamie" == Jamie Lokier <egcs@tantalophile.demon.co.uk> writes:

    Jamie> [Mark: the toupper example is not correct]

Why not?

I have:

  # define __tobody(c, f, a) 
    (__extension__							      
     ({ int __res;							      
	...						      
	__res = a[(int) (c)];						      
	__res; }))

If `c' is `(a + b).c_str()[0]' then a temporary will be created for `a
+ b' when `c' is used as an array index.  That temporary will be
destroyed at the end of the statement:

  __res = a[(int) (c)];

inside the statement expression, which is earlier than the end of the
enclosing full expression.

I'm happy to change the documentation, but I'm confused as to why you
think your original example doesn't illustrate the problem.

--
Mark Mitchell                   mark@codesourcery.com
CodeSourcery, LLC               http://www.codesourcery.com