problem in modular programing

[ashu]

lets look at the code given below
here i m trying to do mudular programming
/* this is my main prog.*/
/*mmod.c*/
#include<stdio. h>
#include "mod1.h"
int main(void)
{
int n;
puts("enter the value of n");
scanf("%d",&n);
printf("the square of %d is :- %ld",n,sqr(n)) ;
return 0;
}

/*this is my secondary module */
/*mod1.c*/
#include "mod1.h"

long sqr(int x)
{
return ((long)((x)*(x) ));
}

/*this is my header file*/
/*mod1.h*/
long sqr(int x);
when i compile main & secondary module,every thing is ok, but as i am

trying to link them,there is a linker error i.e,undefined symbol _sqr

in mmod.exe

[Vladimir S. Oka]

ashu wrote:

lets look at the code given below
here i m trying to do mudular programming
/* this is my main prog.*/
/*mmod.c*/
#include<stdio. h>
#include "mod1.h"
int main(void)
{
int n;
puts("enter the value of n");
scanf("%d",&n);
printf("the square of %d is :- %ld",n,sqr(n)) ;
return 0;
}

/*this is my secondary module */
/*mod1.c*/
#include "mod1.h"

long sqr(int x)
{
return ((long)((x)*(x) ));
}

/*this is my header file*/
/*mod1.h*/
long sqr(int x);
when i compile main & secondary module,every thing is ok, but as i am

trying to link them,there is a linker error i.e,undefined symbol _sqr

in mmod.exe

<OT>
Did you remember to tell your linker about mod1.o[bj]? The exact way
will depend on your toolchain.
</OT>

--
BR, Vladimir

[osmium]

"ashu" writes:

lets look at the code given below
here i m trying to do mudular programming
/* this is my main prog.*/
/*mmod.c*/
#include<stdio. h>
#include "mod1.h"
int main(void)
{
int n;
puts("enter the value of n");
scanf("%d",&n);
printf("the square of %d is :- %ld",n,sqr(n)) ;
return 0;
}

/*this is my secondary module */
/*mod1.c*/
#include "mod1.h"

long sqr(int x)
{
return ((long)((x)*(x) ));
}

/*this is my header file*/
/*mod1.h*/
long sqr(int x);
when i compile main & secondary module,every thing is ok, but as i am

trying to link them,there is a linker error i.e,undefined symbol _sqr

in mood.exe

Looks OK to me. This kind of problem relates to your compiler setup and
this group doesn't discuss such things. So repost to a group dealing with
your compiler. But first,search the group you select for words such as make
file, IDE, project. Use the advanced search of Google groups. It is
unlikely you are the first person to have this problem.

[tmp123]

ashu wrote:

lets look at the code given below
here i m trying to do mudular programming
/* this is my main prog.*/
/*mmod.c*/
#include<stdio. h>
#include "mod1.h"
int main(void)
{
int n;
puts("enter the value of n");
scanf("%d",&n);
printf("the square of %d is :- %ld",n,sqr(n)) ;
return 0;
}

/*this is my secondary module */
/*mod1.c*/
#include "mod1.h"

long sqr(int x)
{
return ((long)((x)*(x) ));
}

/*this is my header file*/
/*mod1.h*/
long sqr(int x);
when i compile main & secondary module,every thing is ok, but as i am

trying to link them,there is a linker error i.e,undefined symbol _sqr

in mmod.exe

Hi,

I do not see any error in your sources that can cause this problem.
It could be a problem with the way you compile and link. In particular,
check the order of the .c files.
If you are doing it with line commands or a makefile, please, post it.

Kind regards.

PS: To all readers: I known the compiler commands are OT, but it is the
best way to discard that error was in the source.

[pemo]

tmp123 wrote:

ashu wrote:

lets look at the code given below
here i m trying to do mudular programming
/* this is my main prog.*/
/*mmod.c*/
#include<stdio. h>
#include "mod1.h"
int main(void)
{
int n;
puts("enter the value of n");
scanf("%d",&n);
printf("the square of %d is :- %ld",n,sqr(n)) ;
return 0;
}

/*this is my secondary module */
/*mod1.c*/
#include "mod1.h"

long sqr(int x)
{
return ((long)((x)*(x) ));
}

/*this is my header file*/
/*mod1.h*/
long sqr(int x);
when i compile main & secondary module,every thing is ok, but as i am

trying to link them,there is a linker error i.e,undefined symbol _sqr

in mmod.exe

Hi,

I do not see any error in your sources that can cause this problem.
It could be a problem with the way you compile and link. In
particular, check the order of the .c files.
If you are doing it with line commands or a makefile, please, post it.

Kind regards.

PS: To all readers: I known the compiler commands are OT, but it is
the best way to discard that error was in the source.

Sounds like you're possibly using Visual C?

The code looks ok, btw, you don't need to include mod1.h in mod1.c - but
it's doing no harm.

If you've got the MS compiler set up to run from a command prompt, then this
should work ...

cl mmod.c mod1.c [output in mmod.exe]

Or, if you just want to use the linker ...

link mmod.obj mod1.obj [output in mmod.exe]

To set up the Microsoft compiler so that it works from a command prompt,
open a command prompt, navigate to ...\Microsoft Visual Studio\VC98\Bin and
run vcvars32
--
==============
*Not a pedant*
==============

[Richard G. Riley]

On 2006-02-22, ashu <ri*********@ya hoo.com> wrote:

lets look at the code given below
here i m trying to do mudular programming
/* this is my main prog.*/
/*mmod.c*/
#include<stdio. h>
#include "mod1.h"
int main(void)
{
int n;
puts("enter the value of n");
scanf("%d",&n);
printf("the square of %d is :- %ld",n,sqr(n)) ;
return 0;
}

/*this is my secondary module */
/*mod1.c*/
#include "mod1.h"

long sqr(int x)
{
return ((long)((x)*(x) ));
}

/*this is my header file*/
/*mod1.h*/
long sqr(int x);
when i compile main & secondary module,every thing is ok, but as i am

trying to link them,there is a linker error i.e,undefined symbol _sqr

in mmod.exe

You are doing something wrong in the linker stage. Can you get the
compiler specific options to compile & link? Check them.

e.g using gcc under linux the following works fine

gcc -g mmod.c mod1.c
../a.out

(runs fine)

One thing : you dont need to include mod1.h into mod1.c : unless
someone can tell me a good reason why one should do so?

There will be a lot of people telling you this is OT for this NG and
they will be kind of right but stick with it - it can all be
confusing when you start :) Learn about make files. Use google.

--
Remove evomer to reply

[tmp123]

Richard G. Riley wrote:

One thing : you dont need to include mod1.h into mod1.c : unless
someone can tell me a good reason why one should do so?

Verify prototypes?

[tmp123]

pemo wrote:

tmp123 wrote:

ashu wrote:

lets look at the code given below
here i m trying to do mudular programming

....
I do not see any error in your sources that can cause this problem.
It could be a problem with the way you compile and link. In
particular, check the order of the .c files.
If you are doing it with line commands or a makefile, please, post it.

Sounds like you're possibly using Visual C?

O, no, me not: VC is too expensive for my bank account.
Was you trying to reply to the OP?

[Chris Dollin]

pemo wrote:

The code looks ok, btw, you don't need to include mod1.h in mod1.c - but
it's doing no harm.

You /should/ so include the .h in the .c; how else can you portably be
sure the compiler is going to detect mismatches between the declaration
and the definition?

--
Chris "was stirred, now shaken" Dollin
RIP Andreas "G'Kar" Katsulas, May 1946 - February 2006

[Richard G. Riley]

On 2006-02-22, Chris Dollin <ke**@hpl.hp.co m> wrote:

pemo wrote:

The code looks ok, btw, you don't need to include mod1.h in mod1.c - but
it's doing no harm.

You /should/ so include the .h in the .c; how else can you portably be
sure the compiler is going to detect mismatches between the declaration
and the definition?

How does that affect including mod1.h into mod1.c?

--
Remove evomer to reply