definition of stdio.h

[lak]

if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

[Ian Collins]

lak wrote:

if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

Either in <stdio.hor a header included by <stdio.h>

--
Ian Collins.

[Richard Heathfield]

Ian Collins said:

lak wrote:

>if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

Either in <stdio.hor a header included by <stdio.h>

Deeply unlikely. Only an idiot would define printf and scanf in a header.
Since you yourself are not an idiot, I think you must have misread his
requirement. He is after the function definitions, not the declarations.

--
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

[Ian Collins]

Richard Heathfield wrote:

Ian Collins said:

>lak wrote:

>>if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

Either in <stdio.hor a header included by <stdio.h>

Deeply unlikely. Only an idiot would define printf and scanf in a header.
Since you yourself are not an idiot, I think you must have misread his
requirement. He is after the function definitions, not the declarations.

:)

A bit odd that the OP's <stdio.honly has symbolic constants.

--
Ian Collins.

[santosh]

lak wrote:

if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

It should be in <stdio.h>. However it might use so many compiler
extensions as to unrecognisable to a beginner or someone who only knows
ISO C. Also as Ian notes, it might be in another file included by
<stdio.h>.

Write a simple program using both printf and scanf and direct the
compiler to produce preprocessed output. If you examine this output
you'll find the declarations for printf and scanf somewhere.

[Richard Tobin]

In article <11**********************@o80g2000hse.googlegroups .com>,
lak <la********@gmail.comwrote:

>if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

You want to look at the source code for the library, which may well
not be available on you system. If you're using Linux, BSD, or some
other free operating system you will be able to get hold of it,
otherwise you're probably out of luck.

You can find the FreeBSD implementation at

http://www.freebsd.org/cgi/cvsweb.cg...ib/libc/stdio/

(click on the red version numbers to see the code).

-- Richard

--
"Consideration shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

[santosh]

Richard Heathfield wrote:

Ian Collins said:

>lak wrote:

>>if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

Either in <stdio.hor a header included by <stdio.h>

Deeply unlikely. Only an idiot would define printf and scanf in a
header. Since you yourself are not an idiot, I think you must have
misread his requirement. He is after the function definitions, not the
declarations.

Oops. I made the same mistake! Oh well.

[Richard Tobin]

In article <fe**********@aioe.org>, santosh <sa*********@gmail.comwrote:

>if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

>If you examine this output
you'll find the declarations for printf and scanf somewhere.

I suspect he really wants the definitions, not the declarations.

-- Richard
--
"Consideration shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

[Keith Thompson]

Richard Heathfield <rj*@see.sig.invalidwrites:

Ian Collins said:

>lak wrote:

>>if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

Either in <stdio.hor a header included by <stdio.h>

Deeply unlikely. Only an idiot would define printf and scanf in a header.

printf and scanf could be defined as macros. (I *think* that C99's
variadic macros are up to the task.)

Since you yourself are not an idiot, I think you must have misread his
requirement. He is after the function definitions, not the declarations.

He asked for definitions, but I'm not convinced that that's really
what he's after (which is why I asked him for clarification
elsethread).

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Richard Tobin]

In article <ln************@nuthaus.mib.org>,
Keith Thompson <ks***@mib.orgwrote:

>whereas the definition is something like this:

int printf(const char * restrict format, ...)
{
/* lots and lots of code here */
}

Probably not "lots and lots", in this case. I suspect that most
implementations will look just like this one from FreeBSD:

int printf(char const * restrict fmt, ...)
{
int ret;
va_list ap;

va_start(ap, fmt);
ret = vfprintf(stdout, fmt, ap);
va_end(ap);
return (ret);
}

-- Richard
--
"Consideration shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

[Army1987]

On Mon, 08 Oct 2007 02:43:16 -0700, Keith Thompson wrote:

Richard Heathfield <rj*@see.sig.invalidwrites:

>Ian Collins said:

>>lak wrote:
if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?

Either in <stdio.hor a header included by <stdio.h>

Deeply unlikely. Only an idiot would define printf and scanf in a header.

printf and scanf could be defined as macros. (I *think* that C99's
variadic macros are up to the task.)

There must be also a real declaration, in case I use
(printf)("foo");
or
#undef printf
printf("foo");
And that one is very unlikely to be also a definition. There still
have to be a (probably precompiled) printf function somewhere.
--
Army1987 (Replace "NOSPAM" with "email")
A hamburger is better than nothing.
Nothing is better than eternal happiness.
Therefore, a hamburger is better than eternal happiness.

[Keith Thompson]

Army1987 <ar******@NOSPAM.itwrites:

On Mon, 08 Oct 2007 02:43:16 -0700, Keith Thompson wrote:

>Richard Heathfield <rj*@see.sig.invalidwrites:

>>Ian Collins said:
lak wrote:
if i view stdio.h there are only symbolic constants.
where is the definition of printf and scanf is available?
i want to see the definition of printf and scanf and where it is
stored?
>
Either in <stdio.hor a header included by <stdio.h>

Deeply unlikely. Only an idiot would define printf and scanf in a header.

printf and scanf could be defined as macros. (I *think* that C99's
variadic macros are up to the task.)

There must be also a real declaration, in case I use
(printf)("foo");
or
#undef printf
printf("foo");
And that one is very unlikely to be also a definition. There still
have to be a (probably precompiled) printf function somewhere.

Sure. My (somewhat silly) point was simply that a non-idiot might
define printf and scanf in a header (though it must also be fully
defined elsewhwere).

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Richard Heathfield]

Keith Thompson said:

>>Richard Heathfield <rj*@see.sig.invalidwrites:

[...] Only an idiot would define printf and scanf in a
header.

[...] My (somewhat silly) point was simply that a non-idiot might
define printf and scanf in a header (though it must also be fully
defined elsewhwere).

Yes, you have made your point well. I must re-phrase my claim to take your
objection into account.

Only an idiot or a completely macro-crazed bozo would define printf and
scanf in a header.

:-)

--
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

[Keith Thompson]

Richard Heathfield <rj*@see.sig.invalidwrites:

Keith Thompson said:

>>>Richard Heathfield <rj*@see.sig.invalidwrites:
>
[...] Only an idiot would define printf and scanf in a
header.

[...] My (somewhat silly) point was simply that a non-idiot might
define printf and scanf in a header (though it must also be fully
defined elsewhwere).

Yes, you have made your point well. I must re-phrase my claim to take your
objection into account.

Only an idiot or a completely macro-crazed bozo would define printf and
scanf in a header.

:-)

printf() is simply fprintf() with the first argument implicitly set to
stdin. Likewise, scanf() is simply fscanf() with the first argument
implicitly set to stdout.

Assuming a C99-compliant compiler, and assuming that C99's variadic
macros are up to the task (I suppose I should confirm that at some
point), I see no reason not to define printf(...) as a macro that
invokes fprintf(stdout, ...) (in addition, of course, to the mandatory
definitions (outside the header) as functions).

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Richard Heathfield]

Keith Thompson said:

<snip>

Assuming a C99-compliant compiler, and assuming that C99's variadic
macros are up to the task (I suppose I should confirm that at some
point), I see no reason not to define printf(...) as a macro that
invokes fprintf(stdout, ...) (in addition, of course, to the mandatory
definitions (outside the header) as functions).

Ah, a very straight bat indeed. Well played, sir. :-)

--
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

[CBFalconer]

Keith Thompson wrote:

>

.... snip ...

>
printf() is simply fprintf() with the first argument implicitly
set to stdin. Likewise, scanf() is simply fscanf() with the first
argument implicitly set to stdout.

I suspect you have performed some unusual operations on the i/o
system before using these macros. :-)

--
Chuck F (cbfalconer at maineline dot net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net>

--
Posted via a free Usenet account from http://www.teranews.com

[Keith Thompson]

CBFalconer <cb********@yahoo.comwrites:

Keith Thompson wrote:
... snip ...

>>
printf() is simply fprintf() with the first argument implicitly
set to stdin. Likewise, scanf() is simply fscanf() with the first
argument implicitly set to stdout.

I suspect you have performed some unusual operations on the i/o
system before using these macros. :-)

Only in my head. (Swap stdin and stdout, of course.)

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Army1987]

On Mon, 08 Oct 2007 15:04:13 -0700, Keith Thompson wrote:

Richard Heathfield <rj*@see.sig.invalidwrites:

>Only an idiot or a completely macro-crazed bozo would define printf and
scanf in a header.

Assuming a C99-compliant compiler, and assuming that C99's variadic
macros are up to the task (I suppose I should confirm that at some
point), I see no reason not to define printf(...) as a macro that
invokes fprintf(stdout, ...) (in addition, of course, to the mandatory
definitions (outside the header) as functions).

Considering that it is very likely that the only differences
between the (real) definitions of printf and fprintf are
+ int printf(const char * restrict format, ...)
- int fprintf(FILE * restrict stream, const char * restrict format, ...)
and
+ ret = vfprintf(stdout, format, ap)
- ret = vfprintf(stream, format, ap)
I can't see any advantage in using the macro...
--
Army1987 (Replace "NOSPAM" with "email")
A hamburger is better than nothing.
Nothing is better than eternal happiness.
Therefore, a hamburger is better than eternal happiness.