Link through Header Files

[rayuthar@gmail.com]

Hi,

I am having three files similar to the stucture given below, while i
execute my test.c, it show error /test.c:5: undefined reference to
`myfunction'.
I have included myprogram.h in both the files myprogram.c and test.c.

if i comment out the line myfunction from myfunction.h, then it is
working properly. Is it multiple definition error?
i compile the files as
cc -c myprogram.c -o myprogram
cc -c test.c -o test
cc -o test test.o my

Thanks in Advance!


/******* myprogram.c *******/

#include "myprogram. h"
myfunction()
{
}


/******* myprogram.h *******/

myfunction();


/******** test.c *********/
#include "myprogram. h"
int main()
{
myfunction();
}

[Richard Heathfield]

Re: Link through Header Files

rayuthar@gmail. com said:

Hi,
>
I am having three files similar to the stucture given below, while i
execute my test.c, it show error /test.c:5: undefined reference to
`myfunction'.
>
I have included myprogram.h in both the files myprogram.c and test.c.
>
if i comment out the line myfunction from myfunction.h, then it is
working properly. Is it multiple definition error?

No - your code has some issues, but it isn't the showstopper in this case.
Rather, it's the way you're invoking the linker.

i compile the files as
cc -c myprogram.c -o myprogram
cc -c test.c -o test
cc -o test test.o my

This can't work, for any reasonable definition of "work".

I suggest you change it, for the time being, to:

cc -c myprogram.c myprogram.o
cc -c test.c -o test.o
cc -o myprogram test.o myprogram.o

<snip>

--
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]

Re: Link through Header Files

rayuthar@gmail. com wrote:

Hi,
>
I am having three files similar to the stucture given below, while i
execute my test.c, it show error /test.c:5: undefined reference to
`myfunction'.
I have included myprogram.h in both the files myprogram.c and test.c.
>
if i comment out the line myfunction from myfunction.h, then it is
working properly. Is it multiple definition error?
i compile the files as
cc -c myprogram.c -o myprogram
cc -c test.c -o test
cc -o test test.o my
>

Where's myprogram in the line above?

>
/******* myprogram.h *******/
>
myfunction();
>

Don't use implicit it return, please.



--
Ian Collins.

[Keith Thompson]

Re: Link through Header Files

Richard Heathfield <rjh@see.sig.in validwrites:

rayuthar@gmail. com said:

[...]

>i compile the files as
>cc -c myprogram.c -o myprogram
>cc -c test.c -o test
>cc -o test test.o my

>
This can't work, for any reasonable definition of "work".
>
I suggest you change it, for the time being, to:
>
cc -c myprogram.c myprogram.o
cc -c test.c -o test.o
cc -o myprogram test.o myprogram.o

You missed the "-o" on the first line.

For that matter, the first two commands can be simplified by using the
default output file name:

cc -c myprogram.c
cc -c test.c

though the "-o" does show more explicitly what's going on.

Note that this is about a particular implementation, not about C.
For more details, consult your system's documentation for the "cc"
command, or ask in comp.unix.progr ammer.

--
Keith Thompson (The_Other_Keit h) <kst-u@mib.org>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Richard Heathfield]

Re: Link through Header Files

Keith Thompson said:

<snip>

You missed the "-o" on the first line.

So I did.

--
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

[rayuthar@gmail.com]

Re: Link through Header Files

On Apr 14, 11:04 pm, Richard Heathfield <r...@see.sig.i nvalidwrote:

Keith Thompson said:
>
<snip>
>

You missed the "-o" on the first line.

>
So I did.
>
--
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

Thanks to everyone! But i found out the problem and fault was mine. i
was trying to invoke a static function from another c file!