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#ifndef does not work properly

Hello!

I want to include the same headerfile in more than one sourcefile and of course have to take care that each Headerfile is included just once.

I really have no clue, why this works for the Headers provided by Keil but not with my own ones:

#ifndef _MYHEADER_H_
#define _MYHEADER_H_

//Headerfile content
. ..

#endif

Obviously the preprocessor includes the Headerfile more than once and so i get errors.

When i add a statement within my Header like:

#warning "included more than once"

the warning message appears twice. (so the header is really included twice).

Can anyone tell me the problem please?!

Kind regards

Parents

0 Jo Leeuwesteijn over 18 years ago in reply to Jo Leeuwesteijn

Example 2 should have read:

Example 2:
global.h
header1.h -> includes global.h
header2.h -> includes global.h as well
file1.c -> include header1.h -> OK
           include header2.h -> ERROR, global.h already included
file2.c -> include header1.h -> OK
           include header2.h -> ERROR, global.h already included

Sorry about that...

--
J

Reply

0 Jo Leeuwesteijn over 18 years ago in reply to Jo Leeuwesteijn

Example 2 should have read:

Example 2:
global.h
header1.h -> includes global.h
header2.h -> includes global.h as well
file1.c -> include header1.h -> OK
           include header2.h -> ERROR, global.h already included
file2.c -> include header1.h -> OK
           include header2.h -> ERROR, global.h already included

Sorry about that...

--
J

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