[PATCH 2/2] Y2038: make __tz_convert compatible with 64-bit-time

[Joseph Myers]

On Wed, 13 Jun 2018, Paul Eggert wrote:

> I don't see why 64-bit platforms need two entry points. If time_t is 64 bits,
> ctime and __ctime64 can be aliases, no? Also, it's a bit cleaner to declare
> and initialize t64 at the same time, i.e., '__time64_t t64 = *t;'; we can
> assume this C99ism in glibc nowadays.

My suggestion is that an internal header does

#if !__TIME32_SUPPORTED
# define __ctime64 ctime
#endif

and then the definition of the 32-bit ctime wrapper is conditional on "#if 
__TIME32_SUPPORTED", so that the main 64-bit version just gets compiled as 
ctime in the case where time_t has always only been 64-bit for this ABI.

That way, internal code can call the __*64 interfaces unconditionally and 
the calls will just end up calling the non-*64 interfaces when the *64 
interfaces don't need to exist as separate functions - and no exports of 
*64 in the public ABI are needed in that case either.

-- 
Joseph S. Myers
joseph@codesourcery.com