-std's (was Re: v3 link failures analyzed)

[Joseph S. Myers]

On 10 Jan 2001, Gabriel Dos Reis wrote:

> Thanks.  Now I understand the motivation.  But I still think that
> there should be an alias for the most recent standard in effect
> (and understood by the compiler).

Under what circumstances would such an option be useful?

In a controlled environment, the compiler version used everywhere is
known, and the standard option can be specified in a single place.

In an uncontrolled environment (code distributed widely), if the source is
written to a standard then it's presumably written to a particular edition
of the standard.  In any case, it presumably has a standard version (maybe
a GNU one) with which it's known to work, and using a later one because a
newer compiler happens to support it would just risk gratuitous breakage.
If you want to specify a standard (rather than risk breakage as the
default goes gnu89 -> gnu99 -> gnu0x -> ...), why risk breakage by using
an unknown latest version?

What counts as "understood by the compiler"?  Does GCC presently
understand C99 (the -std option is there, but many features are missing)?

-- 
Joseph S. Myers
jsm28@cam.ac.uk