(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?
Similarly, how would a "constant value" minus one, (as in line 11) also
not be a constant?
This seems too obvious for it not to have been caught before. Is this a
designed feature deficit, or did I really stumble upon a bug in such
mature code that it wouldn't have been reported and fixed years ago?
:-)
I've also included same program, below, without line numbers (for easy
cut & paste to a test file).
Am I missing something about constant folding, or is it this some unlikely
fluke?
Thanks,
Linda
---------------------
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
typedef const char * String;
static const String days [] ={"Sun", "Mon", "Tue", "Wed", "Thu" , "Fri", "Sat"};
static const int sizeof_days = sizeof(days);
static const int sizeof_String = sizeof(String);
static const int numdays = sizeof_days / sizeof_String;
static const int last_index=numdays-1;
int main (){
printf("numdays=%d, lastidx=%d\n",numdays,last_index);
}
-----------------------------
