fopen

**Walter Roberson** · Jun 27 '08, 07:41 PM

Re: fopen

In article <VgA5k.40538$lE 3.23882@trnddc0 5>,
Bill Cunningham <nospam@nspam.c omwrote:

I have a question about fopen. I want to append text to a text file
>already written. I think this is what I need to do. If I am correct fopen's
>second parameter takes only 2 letters.

No, there are well-defined three-character sequences.

>I am using wt.

The standard does not define the meaning of 't', only of 'b' (binary).
Text is assumed if binary is not specified.

To append text would I
>need another call to fopen if my text file isn't already existing consisting
>of wa or a+ ? How can I check if an existing text file exists that has been
>created before ?

fopen() with 'a'. ftell() your current position, fseek() to the
beginning of the file, and ftell() again. If the first ftell()
result is the same as the second ftell() then you started out at
the beginning of the file and so there was no existing text.

(Note: If I recall correctly, in some systems when using text streams,
the initial file position is officially considered to be "one past"
the end of file, rather than right -at- the end of file. The writes
still work the same way, but if my memory is correct on this point,
then ftell() on a newly-created text file might not return the
same value as ftell() from the "beginning" of the same file.)
--
"Product of a myriad various minds and contending tongues, compact of
obscure and minute association, a language has its own abundant and
often recondite laws, in the habitual and summary recognition of
which scholarship consists." -- Walter Pater

**Serve Lau** · Jun 27 '08, 07:41 PM

Re: fopen

"Bill Cunningham" <nospam@nspam.c omschreef in bericht
news:VgA5k.4053 8$lE3.23882@trn ddc05...

I have a question about fopen. I want to append text to a text file
already written. I think this is what I need to do. If I am correct
fopen's second parameter takes only 2 letters. I am using wt. To append
text would I need another call to fopen if my text file isn't already
existing consisting of wa or a+ ?

read your favorite C book and try it out, its in there no matter if its a
good or bad book

**vippstar@gmail.com** · Jun 27 '08, 07:41 PM

Re: fopen

On Jun 16, 11:44 pm, "Bill Cunningham" <nos...@nspam.c omwrote:

I have a question about fopen. I want to append text to a text file
already written. I think this is what I need to do. If I am correct fopen's
second parameter takes only 2 letters. I am using wt.

People have already told you numerous times 't' is non-standard.
How many more times do you need to be told 't' is non-standard?
Here, once more: 't' is non-standard.

Just in case: 't' *is* *non*-standard.

**Bill Cunningham** · Jun 27 '08, 07:41 PM

Re: fopen

"Serve Lau" <nihao@qinqin.c omwrote in message
news:e8de8$4856 df32$541fc2ec$3 0325@cache5.til bu1.nb.home.nl. ..

read your favorite C book and try it out, its in there no matter if its a
good or bad book

Already checked it. I will check out the mentioned functions. Always
wondered what fpos did. I'll check ftell and such.

Bill

**Bill Cunningham** · Jun 27 '08, 07:41 PM

Re: fopen

"Walter Roberson" <roberson@ibd.n rc-cnrc.gc.cawrote in message
news:g36kmr$l0s $1@canopus.cc.u manitoba.ca...

The standard does not define the meaning of 't', only of 'b' (binary).
Text is assumed if binary is not specified.

[snip]

I heard something about Microsoft and the 't'. If it isn't standard why use
it. What does M$ have to do with this anyway? I just won't use it anymore. I
will work with the functions you mentioned thanks very much.

Bill

**Bill Cunningham** · Jun 27 '08, 07:41 PM

Re: fopen

"Walter Roberson" <roberson@ibd.n rc-cnrc.gc.cawrote in message
news:g36kmr$l0s $1@canopus.cc.u manitoba.ca...

I've tried this. Every new number overwites the last. Here is the code I can
see I don't know how to use fseek.

#include <stdio.h>
#include <stdlib.h>

int
main (int argc, char *argv[])
{
if (argc != 2)
{
puts ("usage error");
exit (EXIT_FAILURE);
}
double x;
x = strtod (argv[1], NULL);
FILE *fp;
fp = fopen ("data", "wa");
fprintf(fp,"%.2 f\n",x);
ftell(fp);
fseek(fp,0,1);
ftell(fp);
fclose (fp);
return 0;
}

What did I do wrong?

Bill

**Bill Cunningham** · Jun 27 '08, 07:41 PM

Re: fopen

<vippstar@gmail .comwrote in message
news:2ae5b151-a56c-4395-bd3b-806ca28b892f@8g 2000hse.googleg roups.com...

People have already told you numerous times 't' is non-standard.
How many more times do you need to be told 't' is non-standard?
Here, once more: 't' is non-standard.
>
>
>
Just in case: 't' *is* *non*-standard.

Hum don't remember talking about it. I remember something mentioned
about M$ and t. Well no matter. I can see I can count on you for help that
is not needed. Have I not made to your killfile yet? What can I do to help?
You're in mine.

Bill

**Bill Cunningham** · Jun 27 '08, 07:41 PM

Re: fopen

"Bill Cunningham" <nospam@nspam.c omwrote in message
news:66D5k.2094 8$3j2.17956@trn ddc03...

>
"Serve Lau" <nihao@qinqin.c omwrote in message
news:e8de8$4856 df32$541fc2ec$3 0325@cache5.til bu1.nb.home.nl. ..

You know my book doesn't give return values for these functions for
error checking. What about ftell and fseek do they return -1 or non zero
when successful ?

Bill

**Richard Heathfield** · Jun 27 '08, 07:41 PM

Re: fopen

Bill Cunningham said:

<snip>

Have I not made to your killfile yet? What can I do
to help? You're in mine.

If he really were in your killfile, you would not have seen his article.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

**Bill Cunningham** · Jun 27 '08, 07:41 PM

Re: fopen

"Richard Heathfield" <rjh@see.sig.in validwrote in message
news:_uOdnf1Ika L5gsrVnZ2dneKdn ZydnZ2d@bt.com. ..

If he really were in your killfile, you would not have seen his article.
>

I use OE. There's no killfile there. I just don't read posts from certain
persons. I know agent has a killfile. There comes a time to not read some
posts. A "killfile".

Bill

**Richard Heathfield** · Jun 27 '08, 07:41 PM

Re: fopen

Bill Cunningham said:

>
"Bill Cunningham" <nospam@nspam.c omwrote in message
news:66D5k.2094 8$3j2.17956@trn ddc03...

>>
>"Serve Lau" <nihao@qinqin.c omwrote in message
>news:e8de8$485 6df32$541fc2ec$ 30325@cache5.ti lbu1.nb.home.nl ...

>
You know my book doesn't give return values for these functions for
error checking.

In message <3d38f60e_3@cor p.newsgroups.co m(posted on 20 July 2002) you
wrote:

"This little K&R2 book is giving me the devil of a time."

It is not unreasonable to deduce from that statement that you have had a
copy of K&R2 since at least 2002.

Despite your claim, K&R2 *does* document the return value semantics for
fopen, freopen, fflush, fclose, fprintf, fscanf, fgetc, fgets, fputc,
fputs, fread, fwrite, fseek, ftell, fgetpos, and fsetpos - on pp242-248.

What about ftell and fseek do they return -1 or non zero
when successful ?

Read the book.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

**Richard Heathfield** · Jun 27 '08, 07:41 PM

Re: fopen

Bill Cunningham said:

>
"Richard Heathfield" <rjh@see.sig.in validwrote in message
news:_uOdnf1Ika L5gsrVnZ2dneKdn ZydnZ2d@bt.com. ..

>If he really were in your killfile, you would not have seen his article.
>>

I use OE. There's no killfile there.

Then he can't be in one, can he?

I just don't read posts from certain persons.

If that were true, you would not have read his article, so there would have
been no cause to respond to it.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

**Richard** · Jun 27 '08, 07:41 PM

Re: fopen

"Bill Cunningham" <nospam@nspam.c omwrites:

I have a question about fopen. I want to append text to a text file
already written. I think this is what I need to do. If I am correct fopen's
second parameter takes only 2 letters. I am using wt. To append text would I
need another call to fopen if my text file isn't already existing consisting
of wa or a+ ? How can I check if an existing text file exists that has been
created before ?
>
Bill

Try reading the man page Bill. I hear it helps.

**Richard** · Jun 27 '08, 07:41 PM

Re: fopen

"Bill Cunningham" <nospam@nspam.c omwrites:

"Walter Roberson" <roberson@ibd.n rc-cnrc.gc.cawrote in message
news:g36kmr$l0s $1@canopus.cc.u manitoba.ca...
>

>The standard does not define the meaning of 't', only of 'b' (binary).
>Text is assumed if binary is not specified.

[snip]
>
I heard something about Microsoft and the 't'. If it isn't standard why use
it. What does M$ have to do with this anyway? I just won't use it anymore. I
will work with the functions you mentioned thanks very much.
>
Bill

Alright, give it up Kenny. It's not funny anymore :-)

fopen

fopen

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