| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Michael Meskes <meskes(at)postgresql(dot)org> |
| Cc: | PostgreSQL Hacker <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Warnings in compile |
| Date: | 2009-05-25 16:10:49 |
| Message-ID: | 4263.1243267849@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Michael Meskes <meskes(at)postgresql(dot)org> writes:
> On Mon, May 25, 2009 at 11:27:27AM -0400, Tom Lane wrote:
>> You can't just remove the "else", or it's unsafe;
> But why? What does this empty else accomplish?
Consider
if (...)
macro;
else
something-else;
Without the "else" in the macro, this code would be parsed
in a surprising fashion, ie else bound to the wrong if.
I'm afraid that "else {}" might not be any better --- it
might fail outright in this context.
[ thinks for a bit... ] What might be both safe and warning-free
is to code an explicit empty statement, viz macro body as
if (1) { ... } else ((void) 0)
regards, tom lane
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