A quick question

[Christopher Benson-Manica]

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

(It's the last of these that I'm specifically wondering about.)

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

[Darrell Grainger]

On Thu, 5 Feb 2004, Christopher Benson-Manica wrote:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

(It's the last of these that I'm specifically wondering about.)
The fact that the standard C89, 7.9.6.3 The printf function, states:

The printf function is equivalent to fprintf with the argument
stdout interposed before the arguments to printf."

Makes it fairly certain that the first two are guaranteed to produce the
same output.

The only limitation I can find is that fprintf and printf may have an
environmental limit but fwrite does not; 7.9.6.1 The fprintf function,
"The minimum value for the maximum number of characters produced by any
single conversion shall be 509."

P.S. sizeof char == 1 therefore you could write it as:

fwrite( s, 1, sizeof(s) - 1, stdout );
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

--
Send e-mail to: darrell at cs dot toronto dot edu
Don't send e-mail to vi************@ whitehouse.gov

[Mark A. Odell]

Christopher Benson-Manica <at***@nospam.c yberspace.org> wrote in
news:bv******** **@chessie.cirr .com:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

I thought sizeof (char) was *guaranteed* to be one?

--
- Mark ->
--

[Thomas Stegen CES2000]

Christopher Benson-Manica wrote:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
This is basically the definition of printf
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

Yup, from my reading of the standard. All call above are allowed to
fail in different ways, but as long as then completely succeed the
output will be the same. Note that fwrite have to write the output
as if it was written with fputc. That is, for each element to be
written (the third argument) fputc shall write out as many bytes
as specified by the second argument. Each of these bytes shall be
successive. (Of course, an implementation need only behave as-if
fputc is being used).

--
Thomas.

[Régis Troadec]

Hello,

"Christophe r Benson-Manica" <at***@nospam.c yberspace.org> a écrit dans le
message de news: bv**********@ch essie.cirr.com. ..

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

(It's the last of these that I'm specifically wondering about.)
I would answer yes, since you don't include the terminating null character
by using fwrite, it acts like using printf() and fprintf() with the %s flag.

best regards, regis
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

[Eric Sosman]

Christopher Benson-Manica wrote:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

(It's the last of these that I'm specifically wondering about.)

Yes: Assuming `stdout' does not have "wide orientation"
(7.19.2/4-5) and barring I/O errors, all of these produce the
same result as `fputs(s, stdout)'. "The byte output functions
write characters to the stream as if by successive calls to the
fputc function." (7.19.3/12)

Of course, if you mis-counted and wrote `s[14]' or `s[16]',
this wouldn't be true.

--
Er*********@sun .com

[Christopher Benson-Manica]

Eric Sosman <Er*********@su n.com> spoke thus:

char s[15]="Hello, world\n!"; fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

Of course, if you mis-counted and wrote `s[14]' or `s[16]',
this wouldn't be true.

Which is why I'm of the opinion that fixed-width strings, and this
method of dealing with them, are not to be preferred.

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

[Artie Gold]

Mark A. Odell wrote:

Christopher Benson-Manica <at***@nospam.c yberspace.org> wrote in
news:bv******** **@chessie.cirr .com:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

I thought sizeof (char) was *guaranteed* to be one?

'Tis.

--ag

--
Artie Gold -- Austin, Texas

"Yeah. It's an urban legend. But it's a *great* urban legend!"

[Joe Wright]

Christopher Benson-Manica wrote:

Given the following:

char s[15]="Hello, world\n!";

Are all the following guaranteed to produce the same output?

printf( "%s", s );
fprintf( stdout, "%s", s );
fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

(It's the last of these that I'm specifically wondering about.)

Sorry I'm late. It is the last line that is of interest. The first
problem is that 'sizeof s' is of no interest as it might well be 256 or
somesuch. I would write the third line..

#include <string.h>
...
fwrite(s, 1, strlen(s), stdout);

I don't know where the -1 stuff comes from. Also the initializer of s
looks strange as...

"Hello, world\n!"

It is usally...

"Hello, world!\n"
^^^
--
Joe Wright http://www.jw-wright.com
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Christopher Benson-Manica]

Joe Wright <jo********@ear thlink.net> spoke thus:

fwrite( s, sizeof(char), sizeof(s)/sizeof(char) - 1, stdout );

'sizeof s' is of no interest as it might well be 256 or
somesuch.
Not so, if other replies are to be believed (as well as a great deal
of code produced by better hands than mine). sizeof s yields 15 here,
although I would be grateful if someone would post the portion of the
Standard, if any, which guarantees that.
I don't know where the -1 stuff comes from.
I specifically wished to avoid printing the NUL terminator.
Also the initializer of s looks strange as... "Hello, world\n!"

Indeed, typos often grate upon the eye. Sorry.

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.