Date: Sun, 3 Jun 2001 12:57:58 -0400 From: Garance A Drosihn <drosih@rpi.edu> To: Poul-Henning Kamp <phk@critter.freebsd.dk>, Peter Wemm <peter@wemm.org> Cc: John Polstra <jdp@polstra.com>, arch@FreeBSD.ORG Subject: Re: time_t definition is wrong Message-ID: <p05100e0fb74019e19da6@[128.113.24.47]> In-Reply-To: <45913.991557175@critter> References: <45913.991557175@critter>
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At 10:32 AM +0200 6/3/01, Poul-Henning Kamp wrote:
>Most of the trouble here is printf. What we need is to be able
>to say something like
>
> printf("time= %{time_t}\n", time_second);
The following is what Garrett noted in this thread in -stable.
I'm not sure where this leaves us, other than it shows that
no matter what type we pick for type_t, there will still be
some portability problems, at least when it comes to printing.
It looks like the best way to solve the printing-issue is to
always use strftime().
- Garance
- - - -
At 8:33 PM -0400 6/2/01, Garrett Wollman wrote:
> The pw->pw_chage and pw->pw_passwd are of time_t. But,
> in the above, %ld is used for them.
This is a general problem; there is no portable way to print
a time_t that does not include the following steps:
1) Determine whether time_t is integral, floating-point, or
(new in C99) complex.
2) If time_t is integral, determine whether it is signed or
unsigned.
3) If the compilation environment is not C99, and time_t is
integral, cast to (appropriately signed) long and print
with %ld or %lu as appropriate. If the compilation
environment is (close enough to) C99, cast to
(appropriately signed) intmax_t and print with %jd or %ju
as appropriate. If time_t is floating-point, cast to long
double and print with %Lf. If time_t is complex, you have
a lot more serious problems to deal with.
There is a simple way around this, for POSIX systems only: use
strftime() with the %s format.
-GAWollman
- - - -
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