Maybe we need to distinguish between a const variable and a literal.
> Linda A. Walsh wrote:
> > (Sorry if this is a dup, somehow my from address got mangled with
the from
> > addr having this message being sent from my system's MAILER DAEMON!
> > Weird.)
> >
> > I have a "proglet", included below (twice, in fact! :-), first with line
> > numbering for referring to the error messages, and a 2nd time without
> > line numbers to allow for easy cut & pasting to try it in your local
> > environment.
> >
> > The error output appears to indicate a problem with compile-time
constant
> > folding.
> >
> > gcc --version shows:
> > gcc (SUSE Linux) 4.3.2 [gcc-4_3-branch revision 141291]
> >
> > Compile time output:
> > ct.c:10: error: initializer element is not constant
> > ct.c:11: error: initializer element is not constant
> >
> > Here's the proglet w/line numbering for reference:
> > ------
> > 1 #include <stdio.h>
> > 2 #include <stdlib.h>
> > 3 #include <strings.h>
> > 4 5 typedef const char * String;
> > 6 7 static const String days [] ={"Sun", "Mon", "Tue", "Wed", "Thu" ,
> > "Fri", "Sat"};
> > 8 static const int sizeof_days = sizeof(days);
> > 9 static const int sizeof_String = sizeof(String);
> > 10 static const int numdays = sizeof_days /
sizeof_String;
> > 11 static const int last_index=numdays-1;
> > 12 13 int main (){
> > 14 printf("numdays=%d, lastidx=%d\n",numdays,last_index);
> > 15 }
> > --------
> >
> > if, in line 8, sizeof(days) is a constant, AND in line 9,
> > sizeof(String) is
> > a constant, then how can their division (in line 10) NOT be a constant?
>
> Simple: sizeof(days) is a constant, but sizeof_days is not. Reason:
because
> the C language standard says so. A const variable is not a constant.
It'd be
> nice if it were.
>
> Andrew.
>
>
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