On 2024-04-21 14:36, Bruno Haible wrote:
But direct use of off_t has two problems:
- off_t is not defined by ISO C; thus it's an odd return type for things
like zsprintf.
I was thinking that zsprintf should return ptrdiff_t and zprintf would
return off_t. off_t is defined by POSIX <stdio.h>, so it's reasonable
for zprintf to use it.
- off_t changes depending on whether gl_LARGEFILE is in use or not;
thus it's a bad idea to use it in the API of any shared library or
(more generally) any independently-built component.
That ship sailed long ago, I'm afraid. That is, any API depending on I/O
sizes must deal with this problem anyway, so there's nothing new here.
(Also, the problem will go away soon enough anyway, as 32-bit off_t
systems will likely die out by 2038 due to time_t issues of all things....)
I would prefer to solve this dilemma by defining a new type, say 'zoff_t',
that is required to be
- at least as wide as off_t, and
- at least as wide as ptrditt_t.
That should also work. Not sure whether it's better than using off_t for
I/O and ptrdiff_t for main memory, though. Both approaches have pros and
cons. An advantage of the off_t/ptrdiff_t approach is that it does not
introduce a new type with all the confusion that would bring (there's a
reason regoff_t has been so unpopular - even glibc doesn't implement it
properly if memory serves...).
