Need Help Parsing From File

[John Machin]

On 8/12/2006 1:53 PM, Gabriel Genellina wrote:
> At Thursday 7/12/2006 15:44, John Machin wrote:
> 
>> > > > ftxt=open(filename,"rt")
>> > >
>> > >Is this a bug or a feature? Or is it one of those good old 
>> "unspecified
>> > >behaviour" cases? MSVC rtl only?
>> >
>> > The Python docs say only that the initial letter is checked. And the
>> > ANSI 89 C says that other characters may follow after r, r+, etc.
>> > "rt" is useless for an ANSI C compiler, since the default stream mode
>> > is "text" -on systems which differentiate between text and binary-
>> > and irrelevant on systems which don't do such distinction.
>> > (And since I got used to write "rt",
>>
>> Why did you do that?
>> (1) Text mode is was and ever shall be the default, even with MS.
> 
> No, there used to be a flag in the stdio library, giving the default 
> value when neither t or b was specified.
> For the Borland C++ 3.1 help (about 1991):
>  If "t" or "b" is not given in the string, the mode is governed by _fmode.
>      If _fmode is set to O_BINARY, files are opened in binary mode.
>      If _fmode is set to O_TEXT, they are opened in text mode.
> MSC used to have a similar flag (perhaps using the same name).

Indeed, and their docs say that the default for _fmode is text mode.

> All of this predates wide usage of ANSI C 89, which made the "t" flag 
> obsolete.
> 
>> (2) Seeing we're referring to docs and standards: Microsoft C 5.0
>> Optimizing Compiler, Run-Time Library Reference manual says "The t
>> option is not part of the ANSI standard for open, but is a Microsoft
>> extension and should not be used where ANSI portability is required".
> 
> A "t" after the initial recognized characters should be ignored by any 
> conforming compiler. I think the idea was to allow for extensions like 
> fopen(fn, "rt;reclen=128") but except esoteric platforms I doubt anyone 
> is using that.

So it should be ignored.

So, back to the question: why did you get into the habit of writing "rt" 
  when it was pointless?