any error in the code

[Joe Wright]

Re: any error in the code

Richard Heathfield wrote:

Bartc said:
>

>Richard Heathfield wrote:
>>

>>Well, you're right - I'm forever forgetting to #include <string.h>,
>>and being bluntly reminded of the fact only when I compile the code
>>on a Win32 box

>What's the disadvantage of just including *all* of the standard C headers
>(or more likely creating a single header file that includes them)?

>
Partly, it increases compilation time. But I think most people's *real*
objection to it is that it's inelegant.
>

Yes, it's inelegant. But why does it increase compilation time? The time
required to read the headers must be too trivial to be calculated and
included in 'compilation time'. Or not?

--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Ian Collins]

Re: any error in the code

Joe Wright wrote:

Richard Heathfield wrote:

>Bartc said:
>>

>>Richard Heathfield wrote:
>>>
>>>Well, you're right - I'm forever forgetting to #include <string.h>,
>>>and being bluntly reminded of the fact only when I compile the code
>>>on a Win32 box
>>What's the disadvantage of just including *all* of the standard C
>>headers
>>(or more likely creating a single header file that includes them)?

>>
>Partly, it increases compilation time. But I think most people's
>*real* objection to it is that it's inelegant.
>>

>
Yes, it's inelegant. But why does it increase compilation time? The time
required to read the headers must be too trivial to be calculated and
included in 'compilation time'. Or not?
>

It may even improve compile time if the compiler supports precompiled
headers.

--
Ian Collins.

[Jack Klein]

Re: any error in the code

On Tue, 1 Apr 2008 12:11:44 -0400, lawrence.jones@ siemens.com wrote in
comp.lang.c:

Jack.Thomson.v3 @gmail.com wrote:

Always free the dynamically allocated memory before exitting from the
program

>
Why? Any properly functioning OS will do that automatically after the
program exits, usually much more efficiently than the program can.
>
-Larry Jones

Ahem.

Perhaps because the C standard does not, and cannot, impose
requirements on operating systems. So the C standard neither
guarantees nor even specifies what the result on the platform might be
if a C executable terminates without releasing dynamically allocated
memory.

And in the real world, at least some early versions of MS-DOS were
prone to displaying an error message along the lines of "Memory Arena
Corrupted, System Halted" and locking up if programs exited without
releasing allocated memory.

I wouldn't be surprised if there were some oddball niche operating
systems around today that might have problems, even if popular desktop
OS's handle the situation.

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://c-faq.com/
comp.lang.c++ http://www.parashift.com/c++-faq-lite/
alt.comp.lang.l earn.c-c++

http://www.club.cc.cmu.edu/~ajo/docs/FAQ-acllc.html

[Richard Heathfield]

Re: any error in the code

Harald van D?k said:

<snip>

However, even then it's possible to disable this by adding -fno-builtin
to the compiler options.

....which is all completely off-topic here, of course (but that hasn't
stopped me from gratefully adding -fno-builtin to my makefile generator).

--
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

[parag_paul@hotmail.com]

Re: any error in the code

On Apr 2, 11:14 am, Richard Heathfield <r...@see.sig.i nvalidwrote:

Harald van D?k said:
>
<snip>
>

However, even then it's possible to disable this by adding -fno-builtin
to the compiler options.

>
...which is all completely off-topic here, of course (but that hasn't
stopped me from gratefully adding -fno-builtin to my makefile generator).
>
--
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

HI All
Thank you all for letting so many views out on this .

I also wanted to know, whether there is any error in the way the
function Error is defined. Well, if it exists from this function , it
definitely measn that we dont need to free anything , do we>

Even after the returned value is a NULL;
I am giving the full code here
#include <stdlib.h>
#include <stdio.h>
void Error(char* s)
{
printf(s);
return;
}

int main()
{
int *p;
p = (int*)malloc(si zeof(int));
if(p == NULL)
{
Error("Could not allocate the memory\n");
Error("Quitting ....\n");
exit(1);
}
else
{
/*some stuff to use p*/
}
return 0;
}

[Richard Heathfield]

Re: any error in the code

parag_paul@hotm ail.com said:

<snip>

I also wanted to know, whether there is any error in the way the
function Error is defined. Well, if it exists from this function , it
definitely measn that we dont need to free anything , do we>
>
Even after the returned value is a NULL;
I am giving the full code here
#include <stdlib.h>
#include <stdio.h>
void Error(char* s)
{
printf(s);
return;
}

Careful. Think about what printf will think, if s contains any % signs!

What do you think of this replacement?

void error(FILE *fp, const char *s)
{
fprintf(fp, "Error: %s\n", s);
}

int main()
{
int *p;
p = (int*)malloc(si zeof(int));

p = malloc(sizeof *p);

But why allocate memory for a single int? Wouldn't it be easier to do:

int i;

if(p == NULL)
{
Error("Could not allocate the memory\n");
Error("Quitting ....\n");
exit(1);

exit(EXIT_FAILU RE);

}
else
{
/*some stuff to use p*/

....followed by free(p);

}
return 0;
}

--
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]

Re: any error in the code

"parag_paul@hot mail.com" wrote:

>
int main() {

should read "int main(void) {".

int *p;
p = (int*)malloc(si zeof(int));

should have no cast. The cast is not needed, and is hiding the
critical error of failing to #include <stdlib.h>

if (p == NULL) {
Error("Could not allocate the memory\n");
Error("Quitting ....\n");
exit(1);

The functions "Error" and "exit" are not declared. Error is not a
standard C function. exit is accessed via #include <stdlib.h>.
The argument '1' for it is not legitimate, the only legal arguments
are 0, EXIT_SUCCESS and EXIT_FAILURE. Again, the EXIT_* values are
declared in <stdlib.h>

}

Here you are missing a "return 0". main returns an int (same as
exit). Do so.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.



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

[Richard Tobin]

Re: any error in the code

In article <8dt5v312qia63j q10oaoubtjj2fse ibrje@4ax.com>,

>Why? Any properly functioning OS will do that automatically after the
>program exits, usually much more efficiently than the program can.

>Perhaps because the C standard does not, and cannot, impose
>requirements on operating systems. So the C standard neither
>guarantees nor even specifies what the result on the platform might be
>if a C executable terminates without releasing dynamically allocated
>memory.

If it can't impose requirements on operating systems, it can't specify
what the result might be if a program terminates after releasing
dynamically allocated memory.

-- Richard
--
:wq

[Bartc]

Re: any error in the code

Joe Wright wrote:

Richard Heathfield wrote:

>Bartc said:
>>

>>Richard Heathfield wrote:
>>>
>>>Well, you're right - I'm forever forgetting to #include <string.h>,
>>>and being bluntly reminded of the fact only when I compile the code
>>>on a Win32 box
>>What's the disadvantage of just including *all* of the standard C
>>headers (or more likely creating a single header file that includes
>>them)?

>>
>Partly, it increases compilation time. But I think most people's
>*real* objection to it is that it's inelegant.
>>

>
Yes, it's inelegant. But why does it increase compilation time? The
time required to read the headers must be too trivial to be
calculated and included in 'compilation time'. Or not?

I'm now using #include "stdhdr.h", which includes all 24 C99 headers, and
the compilation time is still pretty much zero for an empty program.

Total about 3000 lines, compared with some 20000 lines for Windows header
files for example.

Only problem is, when posting code, I need to pick and choose the include
files that are used. Now why didn't something like my stdhdr.h get into the
standard?

And I think my idea is much more elegant than having having some arbitrary,
and slightly different, subset of the 24 headers at the start of every
module, to add to the maintenance work.

--
Bart

[Joachim Schmitz]

Re: any error in the code

Nick Keighley wrote:

On 2 Apr, 08:29, "parag_p...@hot mail.com" <parag_p...@hot mail.com>
wrote:

>On Apr 2, 11:14 am, Richard Heathfield <r...@see.sig.i nvalidwrote:

>

<snip>

>{
>printf(s);

>
this function seems to do almost nothing. It could give
odd behaviour if s contained any % symbols. Use
>
printf "%s\n", s);

rather
printf("%s\n", s);
but better
fprintf(stderr, "%s\n", s);
After all it is supposed to print en error message

Bye, Jojo

[parag_paul@hotmail.com]

Re: any error in the code

On Apr 2, 5:56 pm, "Joachim Schmitz" <nospam.j...@sc hmitz-digital.de>
wrote:

Nick Keighley wrote:

On 2 Apr, 08:29, "parag_p...@hot mail.com" <parag_p...@hot mail.com>
wrote:

On Apr 2, 11:14 am, Richard Heathfield <r...@see.sig.i nvalidwrote:

>
 <snip>

{
printf(s);

>

this function seems to do almost nothing. It could give
odd behaviour if s contained any % symbols. Use

>

    printf "%s\n", s);

>
rather
      printf("%s\n", s);
but better
      fprintf(stderr, "%s\n", s);
After all it is supposed to print en error message
>
Bye, Jojo

Thank you all,

It was a valuable learning experience. But does including strhdr.h
make the compilation procedure costlier

or the compiler has any optimizations like the
#ifndef __STDHDR.H__

-Parag

[santosh]

Re: any error in the code

parag_paul@hotm ail.com wrote:

On Apr 2, 5:56 pm, "Joachim Schmitz" <nospam.j...@sc hmitz-digital.de>
wrote:

>Nick Keighley wrote:

On 2 Apr, 08:29, "parag_p...@hot mail.com" <parag_p...@hot mail.com>
wrote:
>On Apr 2, 11:14 am, Richard Heathfield <r...@see.sig.i nvalid>
>wrote:

>>
><snip>

>{
>printf(s);

>>

this function seems to do almost nothing. It could give
odd behaviour if s contained any % symbols. Use

>>

printf "%s\n", s);

>>
>rather
>printf("%s\n ", s);
>but better
>fprintf(stderr ,"%s\n", s);
>After all it is supposed to print en error message
>>
>Bye, Jojo

>
Thank you all,
>
It was a valuable learning experience. But does including strhdr.h
make the compilation procedure costlier
>
or the compiler has any optimizations like the
#ifndef __STDHDR.H__

No standard header includes any other standard header, and yes,
your "stdhdrs.h" should probably use the customary include guard.