-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 [originally mentioned on bug-bash]
According to Matthew Woehlke on 3/23/2007 3:40 PM: > Eric Blake wrote: >> According to Matthew Woehlke on 3/23/2007 2:40 PM: >>>> SSIZE_MAX is guaranteed to be the maximum value that fits in ssize_t. > > ...that "fits", or that "may be stored in"? > >>>> Again, if your ssize_t is smaller than 32 bits, your platform has other >>>> issues. Just because POSIX allows ssize_t to be as small as 16 bits >>>> doesn't mean many modern platforms do that. >>> Hmm... well then I guess this is broken: >>> /usr/include/limits.h:#define SSIZE_MAX 53248 /* max single >>> I/O size, 52K */ >> >> Which platform is this? > > NSK, naturally. :-) > >> Yes, it is horribly broken; it's not even one >> less than a power of two, which means it is an outright violation of >> this: >> http://www.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html >> {SSIZE_MAX} >> Maximum value of an object of type ssize_t. >> Minimum Acceptable Value: {_POSIX_SSIZE_MAX} > > I'm not convinced. That says "Implementations may choose any appropriate > value for each limit, provided it is not more restrictive than the > Minimum Acceptable Values listed below", and, in this case and *only* > this case, includes the words "...of an object...". While I admit one > might *expect* SSIZE_MAX to refer to the largest /representable/ value, > I don't see (from just that document) what prevents reading it as the > largest /permissible/ value (which is clearly the interpretation NSK > chose). This has potentially severe ramifications to a number of gnulib-based projects. I'm seeking backup from those more knowledgeable about the C and POSIX standards as to whether NSK is allowed to define SSIZE_MAX to something smaller than what the underlying type can hold, and if so, whether it is worth auditing gnulib to find any places that have previously assumed that SSIZE_MAX is ((1<<(sizeof(ssize_t)*CHAR_BIT - 2))-1)*2+1. - -- Don't work too hard, make some time for fun as well! Eric Blake [EMAIL PROTECTED] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (Cygwin) Comment: Public key at home.comcast.net/~ericblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGBE8N84KuGfSFAYARAtXUAKCdN1RpU+KNt2XqkvzqU2T7Uu5HqwCgz5VP KDx8DqCsrplop9tQ68/Bepc= =KYLa -----END PGP SIGNATURE-----
