[Mingw-users] Incompatibility between time_t and 'struct timeval'

[Eli Z. <el...@gn...>]

It seems MinGW runtime 4.x switched to a 64-bit type for time_t by
default.  However, 'struct timeval' still uses 'long tv_sec', which
is a 32-bit type, and is thus incompatible with Posix, whose
requirement is that tv_sec be at least as wide as time_t.

This causes gnulib tests in sys_time_h.m4 to fail and decide that
'struct timeval' needs to be replaced by a Posix-compliant
definition.  See, for example, this discussion on emacs-devel:

  http://lists.gnu.org/archive/html/emacs-devel/2013-09/msg00286.html

and especially this message:

  http://lists.gnu.org/archive/html/emacs-devel/2013-09/msg00361.html

I think I understand the difficulty in fixing this issue, given that
'struct timeval' is used by Windows APIs on which MinGW has no
control.  But if this is not fixed, every project that uses gnulib
(and there are more and more of them lately) will simply replace
'struct timeval' with incompatible definition anyway, which cannot be
good.

So I think the MinGW runtime should do something to make this problem
go away.  E.g., some wrappers around functions that use the structure,
or something.

In any case, even if nothing will be done, I think it's important that
MinGW users be aware of this gotcha.