lkml.org 
[lkml]   [2007]   [Aug]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: gcc fixed size char array initialization bug - known?
Guennadi Liakhovetski wrote:
> On Thu, 2 Aug 2007, Andi Kleen wrote:
>
>> Guennadi Liakhovetski <g.liakhovetski@gmx.de> writes:
>>
>>> char c[4] = "0123";
>>> and - a wonder - no warning.
>> It's required by the C standard.
>>
>> 6.7.8.14 of C99:
>> ``
>> An array of character type may be initialized by a character string literal, optionally
>> enclosed in braces. Successive characters of the character string literal (including the
>> terminating null character if there is room or if the array is of unknown size) initialize the
>> elements of the array.
>> ''
>>
>> Note the "if there is room".
>>
>> I believe the rationale is that it still allows to conveniently initialize
>> non zero terminated strings.
>
> Right, I accept that it will compile, but I don't understand why "01234"
> produces a warning and "0123" doesn't? Don't think C99 says anything about

Because 5 characters will not fit in a 4 character array, even without
the null terminator.

> that. And, AFAIU, using structs with fixed-size char array we more or less
> rely on the compiler warning us if anyone initializes it with too long a
> string.
>
> Also interesting, that with
>
> char c[4] = "012345";
>
> the compiler warns, but actually allocates a 6-byte long array...
>
> Thanks
> Guennadi


--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-08-02 23:45    [W:0.132 / U:0.168 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site