Re: CVS commit: src/crypto/external/bsd/netpgp/dist/src/lib

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

On Sat, Jun 26, 2010 at 05:11:39AM +0200, Alistair Crooks wrote:
> On Sat, Jun 26, 2010 at 01:32:05AM +0200, Joerg Sonnenberger wrote:
> > On Fri, Jun 25, 2010 at 11:54:32PM +0200, Alistair Crooks wrote:
> > >   Even in C99, the "%lu" method will work unless size_t is bigger than
> > >   unsigned long *and* the value being printed exceeds ULONG_MAX, which
> > >   is unlikely to happen in practice.
> 
> Please get the attributions right - I was quoting that text.
>  
> > Actually, it doesn't. This method breaks as soon as size_t != u_long and
> > might only work in a few edge cases like the size_t being the last
> > argument and the byte order is Little Endian. This is worse because IIRC
> > Microsoft decided to use IL32LLP64 or something similarly fancy.
> 
> Can you give us a reference to this, please?

E.g.
http://stackoverflow.com/questions/384502/what-is-the-bit-size-of-long-on-64-bit-windows
and the MSDN reference inside.

> > A more portable approach with autoconf can be found in pkg_install, look
> > for MISSING_SIZE_T_SUPPORT and the corresponding AC_CHECK_SIZEOF calls
> > in configure.ac.
> 
> Hmmm, I see this in configure.ac -
> 
> AC_CHECK_SIZEOF(int)  
> AC_CHECK_SIZEOF(long)   
> AC_CHECK_SIZEOF(long long)
> AC_CHECK_SIZEOF(size_t, [#include <stdlib.h>])

...compute the sizes to not depend on SIZE_MAX (which would simplify the
logic a lot).

> and
> 
> case $host in
> *-*-hpux*)
>         AC_DEFINE(MISSING_SIZE_T_SUPPORT)
>         AH_TEMPLATE([MISSING_SIZE_T_SUPPORT], [ 
>         Define to 1 if the `z' modifider for printf is missing.
> ])
>         ;;
> esac

The only platform for pkgsrc purposes ATM which lacks the %z support.

> and
> 
> #ifndef MISSING_SIZE_T_SUPPORT
> #  define PRIzu "zu"
> #elif SIZEOF_SIZE_T == SIZEOF_INT
> #  define PRIzu "u"
> #elif SIZEOF_SIZE_T == SIZEOF_LONG
> #  define PRIzu "lu"
> #elif SIZEOF_SIZE_T == SIZEOF_LONG_LONG
> #  define PRIzu "llu"
> #else
> #  errror "Unknown size_t size"
> #endif
> 
> Not quite what I'd been expecting, though, from the glowing description
> above.

It would be simpler if SIZE_MAX support can be assumed. In that case it
would boil down to
#if SIZE_MAX == INT_MAX
#define PRIzu "u"
#elif SIZE_MAX == LONG_MAX
#define PRIzu "lu"
#else SIZE_MAX == LLONG_MAX
#define PRIzu "llu"
#endif

Joerg