From Kurt.Hornik@ci.tuwien.ac.at  Thu Aug 19 11:11:09 1999
From: Kurt.Hornik@ci.tuwien.ac.at (Kurt Hornik)
Date: Thu, 19 Aug 1999 12:11:09 +0200 (CEST)
Subject: date() should not append a final "\n" ?!?
In-Reply-To: <199908190948.LAA24138@sophie.ethz.ch>
References: <199908190845.KAA24041@sophie.ethz.ch>
 <14267.50386.581977.851244@galadriel.ci.tuwien.ac.at>
 <199908190938.LAA24130@sophie.ethz.ch>
 <14267.53714.885909.438577@fangorn.ci.tuwien.ac.at>
 <199908190948.LAA24138@sophie.ethz.ch>
Message-ID: <14267.55357.387296.720135@fangorn.ci.tuwien.ac.at>

>>>>> Martin Maechler writes:

>>>>> On Thu, 19 Aug 1999 11:43:46 +0200 (CEST), Kurt Hornik <Kurt.Hornik@ci.tuwien.ac.at> said:
>>>>> Martin Maechler writes:
>>>>> On Thu, 19 Aug 1999 10:45:35 +0200,
>>>>> Martin Maechler (MM) wrote:

MM> Between R 0.63.2 and 0.64, the behavior of 
MM> date()
MM> has been changed in order to become platform independent.
MM> It now uses POSIX calls, basically

MM> time_t t;
MM> time(&t);
MM> return ctime(&t);


MM> This currently returns (for me on Sun SPARC Solaris)

>>>>>> date()
MM> [1] "Thu Aug 19 10:36:28 1999\n"

MM> where I think the final "\n" is really UNdesired.

FrL> Yes!

>>> Okay,
>>> I checked  Lewine (1991) "POSIX Programmer's Guide" :

>>> POSIX specifies that ctime() has a final "\n" 
>>> (before the string terminator \0)
>>> and always length 26 (incl. terminator)

>>> Hence, we have to drop the final "\n",
>>> already in function R_Date() which is [in src/main/platform.c]
>>> currently
>>> char *R_Date()
>>> {
>>> time_t t;
>>> time(&t);
>>> return ctime(&t);
>>> }

>>> How can we drop is this done in the most elegant way?
>>> (without having to allocate a  char[26] ?)

KH> Be brutal, do

KH> date <- function() substring(.Internal(date()), 1, 24)

> Kurt, I said
> 		"most elegant way"
> about 5 lines above..

But you did not define `elegant' ... :-)

> And also for the C API, we want  R_Date() to be correct.

Define `correct'.  That would be without the trailing newline?

> {{I really wonder that the POSIX people where thinking when they
>   appended the "\n";  
>   appending afterwards is always much easier than removing....
> }}


Suggestion:

	return strtok(ctime(&t), "\n");

-k
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date() should not append a final "\n" ?!?
Kurt Hornik