[LCP]Variable Length Arrays in C, support as per C89/C99 in g cc

[Y Giridhar Appaji Nag]

Hi!

> From: Jack Lloyd [mailto:lloyd at acm.jhu.edu]
> Sent: Monday, July 08, 2002 10:53 PM
> To: 'linuxcprogramming at lists.linux.org.au'
> 
> Odd that it
> doesn't give a warning though (are you compiling with "-W -Wall"?).

Yeah! even a -Wall (in addition to -std=c89) does not catch it :(
-pedantic helps though.

> Complying with a particular standard merely means that any 
> valid program in
> that language is accepted by the compiler - since VLAs are completely
> undefined by C90, it seems likely that GCC simply accepts it.

But then if it is compliant to c89 (in which there are no VLAs), wouldn't
this be a deviation ... but when I looked once again into the 'info gcc'
pages ... this is what I found (And it explains the behaviour that I did
encounter). Guess I should've RdTFM closely.

     The `-ansi' option does not cause non-ANSI programs to be rejected
     gratuitously.  For that, `-pedantic' is required in addition to
     `-ansi'.  *Note Warning Options::.

and ...

`-pedantic'
     Issue all the warnings demanded by strict ISO C and ISO C++;
     reject all programs that use forbidden extensions, and some other
     programs that do not follow ISO C and ISO C++.  For ISO C, follows
     the version of the ISO C standard specified by any `-std' option
     used.
	...
     Some users try to use `-pedantic' to check programs for strict ISO
     C conformance.  They soon find that it does not do quite what they
     want: it finds some non-ANSI practices, but not all--only those

> BTW, your code seems wrong. The variable named 'b' is just an 
> int, so you
> can't assign to or read from b[0], b[1], b[2] - presumably 
> you meant to use
> a[0], a[1], a[2] there?

Well it atually was "int a" and "int b[a]" was a type that one.

-rgds,
Giridhar

--
Y Giridhar Appaji Nag       Giridhar.Nag[@t]ubinetics(.)co.in

While one person hesitates because he feels inferior, another
is busy making mistakes and becoming superior. -Henry C. Link 

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