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From: bright@Data-IO.COM (Walter Bright)
Newsgroups: comp.lang.c++
Subject: Re: C++ coding standards (Comment needed)
Keywords: standard,variables
Message-ID: <2675@dataio.Data-IO.COM>
Date: 29 Aug 90 17:20:23 GMT
References: <56642@microsoft.UUCP> <41673@think.Think.COM> <56953@microsoft.UUCP>
Organization: Data I/O Corporation; Redmond, WA
Lines: 23

In article <56953@microsoft.UUCP> jimad@microsoft.UUCP (Jim ADCOCK) writes:
<In article <41673@think.Think.COM> barmar@think.com (Barry Margolin) writes:
<<However, the compiler might decide to grow and shrink the stack frame each
<<time the variable is created and destroyed.
<Hm, do you know of any C++ compiler that actually grows and shrinks a
<the stack within a routine? [in the absense if alloca()s]  A while back
<I read a survey of C compilers that could identify no such compiler.

There *are*, however, compilers that allocate variables on top of each
other if their live ranges do not intersect. This has the same effect
as adjusting the stack.

	func()
	{	{ int i; .... }
		{ int j; .... }
	}

i and j's live ranges do not overlap, so they can (and do with some compilers)
share the same storage location.

<It turns out gotos in the language makes doing such problamatic.

True if you actually are adjusting the SP, but not in the above scheme.