how to create sub-directory if it doesn't exists?

[Martin Jørgensen]

Hi,

I guess in every beginners C-book it writes about how to declare a
filepointer fp and how to create a file (at least in mine)...... Like here:


FILE * fp;
fp = fopen("output_f ile.txt", "w");

if( fp == NULL)
{
printf("Error: File could not be opened\n");
return 1;
}

....
....

But now I would like to test if a given directory exists and if not, I
want to create it so I can put data-files in that sub-directory... How
to do that? And why is that I guess many text-books don't discuss how to
do this?


Best regards / Med venlig hilsen
Martin Jørgensen

--
---------------------------------------------------------------------------
Home of Martin Jørgensen - http://www.martinjoergensen.dk

[osmium]

Re: how to create sub-directory if it doesn't exists?

"Martin Jørgensen" writes:

[color=blue]
> I guess in every beginners C-book it writes about how to declare a
> filepointer fp and how to create a file (at least in mine)...... Like
> here:[/color]
<snip>
[color=blue]
> But now I would like to test if a given directory exists and if not, I
> want to create it so I can put data-files in that sub-directory... How to
> do that? And why is that I guess many text-books don't discuss how to do
> this?[/color]

The base language has no provisions for directories. But each compiler has
some stuff extracted from the API for the associated OS in header files that
will make sense *after* you know which headers they are :-( . So post your
question on a group that discusses your platform.

[David Resnick]

Re: how to create sub-directory if it doesn't exists?


Martin Jørgensen wrote:[color=blue]
> Hi,
>
> I guess in every beginners C-book it writes about how to declare a
> filepointer fp and how to create a file (at least in mine)...... Like here:
>
>
> FILE * fp;
> fp = fopen("output_f ile.txt", "w");
>
> if( fp == NULL)
> {
> printf("Error: File could not be opened\n");
> return 1;
> }
>
> ...
> ...
>
> But now I would like to test if a given directory exists and if not, I
> want to create it so I can put data-files in that sub-directory... How
> to do that? And why is that I guess many text-books don't discuss how to
> do this?
>
>[/color]

You can't do it portably, so a textbook on standard C wouldn't discuss
it much. K&R discusses some directory stuff in its chapter on Unix.
Anyway, see the FAQ:

http://c-faq.com/osdep/mkdir.html

-David

[Robert Latest]

Re: how to create sub-directory if it doesn't exists?

On Wed, 12 Apr 2006 15:49:06 +0200,
Martin Jørgensen <unoder.spam@sp am.jay.net> wrote
in Msg. <j3dvg3-5d4.ln1@news.td c.dk>
[color=blue]
> But now I would like to test if a given directory exists and if not, I
> want to create it so I can put data-files in that sub-directory... How
> to do that? And why is that I guess many text-books don't discuss how to
> do this?[/color]

Because Standard C doesn't know what a "directory" is. FWIW, neither
does this newsgroup.

robert

[Richard G. Riley]

Re: how to create sub-directory if it doesn't exists?

On 2006-04-12, Martin Jørgensen <unoder.spam@sp am.jay.net> wrote:[color=blue]
> Hi,
>
> I guess in every beginners C-book it writes about how to declare a
> filepointer fp and how to create a file (at least in mine)...... Like here:
>
>
> FILE * fp;
> fp = fopen("output_f ile.txt", "w");
>
> if( fp == NULL)
> {
> printf("Error: File could not be opened\n");
> return 1;
> }
>
> ...
> ...
>
> But now I would like to test if a given directory exists and if not, I
> want to create it so I can put data-files in that sub-directory... How
> to do that? And why is that I guess many text-books don't discuss how to
> do this?
>
>
> Best regards / Med venlig hilsen
> Martin Jørgensen
>[/color]

It would depend on the compiler environment. In Gnu C you could
look up mkdir().

[Martin Jørgensen]

Re: how to create sub-directory if it doesn't exists?

David Resnick wrote:[color=blue]
> Martin Jørgensen wrote:[/color]
-snip-
[color=blue]
> You can't do it portably, so a textbook on standard C wouldn't discuss
> it much. K&R discusses some directory stuff in its chapter on Unix.
> Anyway, see the FAQ:
>
> http://c-faq.com/osdep/mkdir.html[/color]

Thanks a lot. That probably tells how to create the directory. And how
to see if the directory exists in the first place?


Best regards / Med venlig hilsen
Martin Jørgensen

--
---------------------------------------------------------------------------
Home of Martin Jørgensen - http://www.martinjoergensen.dk

[Vladimir S. Oka]

Re: how to create sub-directory if it doesn't exists?

Martin Jørgensen opined:
[color=blue]
> David Resnick wrote:[color=green]
>> Martin Jørgensen wrote:[/color]
> -snip-
>[color=green]
>> You can't do it portably, so a textbook on standard C wouldn't
>> discuss
>> it much. K&R discusses some directory stuff in its chapter on Unix.
>> Anyway, see the FAQ:
>>
>> http://c-faq.com/osdep/mkdir.html[/color]
>
> Thanks a lot. That probably tells how to create the directory. And
> how to see if the directory exists in the first place?[/color]

You have to ask in a group that discusses your OS/implementation. As
was mentioned elsethread, Standard C knows nothing about directories.

--
"I once witnessed a long-winded, month-long flamewar over the use of
mice vs. trackballs...It was very silly."
(By Matt Welsh)

<http://clc-wiki.net/wiki/Introduction_to _comp.lang.c>

[David Resnick]

Re: how to create sub-directory if it doesn't exists?


Martin Jørgensen wrote:[color=blue]
> David Resnick wrote:[color=green]
> > Martin Jørgensen wrote:[/color]
> -snip-
>[color=green]
> > You can't do it portably, so a textbook on standard C wouldn't discuss
> > it much. K&R discusses some directory stuff in its chapter on Unix.
> > Anyway, see the FAQ:
> >
> > http://c-faq.com/osdep/mkdir.html[/color]
>
> Thanks a lot. That probably tells how to create the directory. And how
> to see if the directory exists in the first place?
>
>[/color]
So as someone else said, this discussion doesn't really belong
in comp.lang.c. You may get some ideas here:

http://c-faq.com/osdep/fileexists.html

Reading through the FAQ is quite educational, I recommend trying it
as you find time, there is much to learn there.

If you want details on how to do directory manipulation, asking in a
group
dedicated to your particular platform is the way to go. For example,
if you us *nix, asking in comp.unix.progr ammer is a good idea.

-David

[Pedro Graca]

Re: how to create sub-directory if it doesn't exists?

Martin Jørgensen wrote:[color=blue]
> David Resnick wrote:[color=green]
>> You can't do it portably, so a textbook on standard C wouldn't discuss
>> it much. K&R discusses some directory stuff in its chapter on Unix.
>> Anyway, see the FAQ:
>>
>> http://c-faq.com/osdep/mkdir.html[/color]
>
> Thanks a lot. That probably tells how to create the directory. And how
> to see if the directory exists in the first place?[/color]

The first link I followed in the page linked to by David Resnick led me
to a new page, within the 'c-faq' site, with enough information to
learn how to check if a directory exists.

--
If you're posting through Google read <http://cfaj.freeshell. org/google>

[Vladimir S. Oka]

Re: how to create sub-directory if it doesn't exists?

Pedro Graca opined:
[color=blue]
> Martin Jørgensen wrote:[color=green]
>> David Resnick wrote:[color=darkred]
>>> You can't do it portably, so a textbook on standard C wouldn't
>>> discuss
>>> it much. K&R discusses some directory stuff in its chapter on
>>> Unix. Anyway, see the FAQ:
>>>
>>> http://c-faq.com/osdep/mkdir.html[/color]
>>
>> Thanks a lot. That probably tells how to create the directory. And
>> how to see if the directory exists in the first place?[/color]
>
> The first link I followed in the page linked to by David Resnick led
> me to a new page, within the 'c-faq' site, with enough information to
> learn how to check if a directory exists.[/color]

Oh, but that's too difficult!

--
"Whip me. Beat me. Make me maintain AIX."
(By Stephan Zielinski)

<http://clc-wiki.net/wiki/Introduction_to _comp.lang.c>