Re: problem with string.format %d and very large integers

[KHMan <keinhong@...>]

On 7/29/2011 7:47 PM, Lorenzo Donati wrote:
> On 27/07/2011 23.10, Luiz Henrique de Figueiredo wrote:
> > > > =big
> > > 2500000000
> > > > =string.format('%d', big)
> > > -2147483648
> > [snip]
> ---------------------------------------------------------------------
> #include <stdio.h>
> #include <limits.h>
>
> int main()
> {
>
> printf("long long width: %d bit\n", sizeof(long long) * CHAR_BIT );
> long long nnn = 2LL << 30; /* 2^31 */
> double ddd = nnn;
> nnn = ddd; /* check round-trip */
> printf( "ddd = %.0f\n", ddd );
> printf( "nnn = %lld\n", nnn );
>
> }
> ---------------------------------------------------------------------
>
> And compiled it this way:
> gcc test.c -c -O2 -Wall -pedantic -std=c90
> gcc test.o -o test.exe -O2 -Wall -pedantic -std=c90
> [snip]
> So there must be some strange combination of compiler flags in the
> standard makefile that makes GCC do the wrong thing for %lld in
> printf.

A wild guess, perhaps -std=c90 pulls in the mingwex versions of 
*printf. Without the -std=c90, it doesn't work. But putting 
-std=c90 and building the Lua DLL does not appear to work... 
documentation on mingwex is thin on the Internet.

What does work is using __mingw_sprintf in str_format().

Alternatively, Win32 has the "I64" specifier. I dunno how portable 
it is across versions of Win32 >=Win2K.

--
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia