Regarding multiple inclusion of files

[ramsatishv]

Hi,

If I include a ".h" file for multiple times, will it increase my
program size??

Regards
Ram.

[Joachim Schmitz]

<ra********@gmail.comschrieb im Newsbeitrag
news:80**********************************@s8g2000p rg.googlegroups.com...

Hi,

If I include a ".h" file for multiple times, will it increase my
program size??

Unless you do things in these headers that should be done there, like
defining variable rather than just declaring them, no.
However, it's a good idea to prevent that from happening using header guards

#ifndef myheader_h
#define myheader_h
/* your header here */
....
#endif /* myheader_h */
Bye, Jojo

[Ben Pfaff]

ra********@gmail.com writes:

If I include a ".h" file for multiple times, will it increase my
program size??

Normally, no. It might take longer to compile, though.
--
Ben Pfaff
http://benpfaff.org

[Philip Potter]

Joachim Schmitz wrote:

<ra********@gmail.comschrieb im Newsbeitrag
news:80**********************************@s8g2000p rg.googlegroups.com...

>Hi,

If I include a ".h" file for multiple times, will it increase my
program size??

Unless you do things in these headers that should be done there, like
defining variable rather than just declaring them, no.

I think you mean "shouldn't be done". Also, if you define a variable in
a header and include it multiple times, it won't increase your code size
because your code will no longer compile...

However, it's a good idea to prevent that from happening using header guards

#ifndef myheader_h
#define myheader_h
/* your header here */
...
#endif /* myheader_h */

Quite.

[Joachim Schmitz]

"Philip Potter" <pg*@doc.ic.ac.ukschrieb im Newsbeitrag
news:fj**********@aioe.org...

Joachim Schmitz wrote:

><ra********@gmail.comschrieb im Newsbeitrag
news:80**********************************@s8g2000 prg.googlegroups.com...

>>Hi,

If I include a ".h" file for multiple times, will it increase my
program size??

>Unless you do things in these headers that should be done there, like
defining variable rather than just declaring them, no.

I think you mean "shouldn't be done".

Indeed. Fingers faster than brain, yet again...

Also, if you define a variable in a header and include it multiple times,
it won't increase your code size because your code will no longer
compile...

Unless it is included in everal modules

Bye, Jojo

[Malcolm McLean]

"Philip Potter" <pg*@doc.ic.ac.ukwrote in message
news:fj**********@aioe.org...

Joachim Schmitz wrote:

>Unless you do things in these headers that should be done there, like
defining variable rather than just declaring them, no.

I think you mean "shouldn't be done". Also, if you define a variable in a
header and include it multiple times, it won't increase your code size
because your code will no longer compile...

You can make a variable static, so each includer has his own local copy.

This is seldom a good idea.

--
Free games and programming goodies.
http://www.personal.leeds.ac.uk/~bgy1mm

[Chris Dollin]

ra********@gmail.com wrote:

If I include a ".h" file for multiple times, will it increase my
program size??

Multiple times in the same compilation unit, or in different compilation
units?

It depends on the .h file. Typically not, for well-written .h files, but
of course it's possible to arrange otherwise:

fragment.h:

{ 17, 42 },

repeating.c:

static int silly[][2] =
{
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
};

Something like this can even be useful -- `fragment` can depend on a macro
which is #define'd and #undef'd and re-#define'd in `repeating`. But this
happens sufficiently infrequently that you do a sanity check if you come
across it (ie there may well be a better design).

--
Chris "still crazy after all these gears" Dollin

Hewlett-Packard Limited registered office: Cain Road, Bracknell,
registered no: 690597 England Berks RG12 1HN

[Richard Tobin]

In article <fj**********@tadcaster.hpl.hp.com>,
Chris Dollin <ch**********@hp.comwrote:

>It depends on the .h file. Typically not, for well-written .h files, but
of course it's possible to arrange otherwise:

fragment.h:

{ 17, 42 },

repeating.c:

static int silly[][2] =
{
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
};

Something like this can even be useful -- `fragment` can depend on a macro
which is #define'd and #undef'd and re-#define'd in `repeating`. But this
happens sufficiently infrequently that you do a sanity check if you come
across it (ie there may well be a better design).

If you use something like this, I recommend not using the suffix ".h"
for the filename. Keep ".h" for real *h*eader files - that is, files
of declarations rather than miscellaneous bits of C.

-- Richard

--
:wq

[ramsatishv]

On Dec 7, 5:33 pm, [e-mail] (Richard Tobin) wrote:

In article <fjb89d$[e-mail]>,
Chris Dollin <[e-mail]:

It depends on the .h file. Typically not, for well-written .h files, but
of course it's possible to arrange otherwise:

fragment.h:

{ 17, 42 },

repeating.c:

static int silly[][2] =
{
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
#include "fragment.h"
};

Something like this can even be useful -- `fragment` can depend on a macro
which is #define'd and #undef'd and re-#define'd in `repeating`. But this
happens sufficiently infrequently that you do a sanity check if you come
across it (ie there may well be a better design).

If you use something like this, I recommend not using the suffix ".h"
for the filename. Keep ".h" for real *h*eader files - that is, files
of declarations rather than miscellaneous bits of C.

-- Richard

--
:wq- Hide quoted text -

- Show quoted text -

Hi,

Thanks for youre replies. MY situation is something like this:

test.h
--------
#define MACRO 1
void test();
extern int i;

test.c
-------
#include "test.h"
#include "test.h"

int i = 23;

void main()
{
printf("test..");
}

In this case, whether program size increases??

Regards
Satish.

[Joachim Schmitz]

<ra********@gmail.comschrieb im Newsbeitrag
news:69**********************************@i12g2000 prf.googlegroups.com...

Hi,

Thanks for youre replies. MY situation is something like this:

test.h
--------
#define MACRO 1
void test();
extern int i;

test.c
-------
#include "test.h"
#include "test.h"

int i = 23;

void main()
{
printf("test..");
}

In this case, whether program size increases??

No

Bye, Jojo