Header files?

[dominover]

Another questions.

With regards to header files?

Lets say I have a header file 'add.h' .

Can it contain multiple includes all in the same file. eg below.

in add.h
----------------

#ifndef ADD_H
#define ADD_H
void add(int a, int b);
#endif

#ifndef ADD1_H
#define ADD1_H
void add1(int a, int b);
#endif

#ifndef ADD2_H
#define ADD2_H
void add2(int a, int b);
#endif

#ifndef ADD3_H
#define ADD3_H
void add3(int a, int b);
#endif

Thanks

[Peter87]

Is your question if you can have more than one function declaration in a header file? If that's your question the answer is yes, but there is no need to use multiple header guards.

#ifndef ADD_H
#define ADD_H
void add(int a, int b);
void add1(int a, int b);
void add2(int a, int b);
void add3(int a, int b);
#endif 

Strictly speaking you don't need a header guard at all in this case.

[dominover]

Thanks. That was the question and yes your answer answers it perfectly.
so I'm assuming ADD_H is supposed to be aligned with the file name add.h.

Is that correct.

[PavDub]

http://stackoverflow.com/questions/1653958/why-are-ifndef-and-define-used-in-c-header-files

http://en.wikipedia.org/wiki/Include_guard

... and others, google

#ifndef header

---

ps.> if you read the above and study preprocessor directives carefully, you should understand that "ifndef" in your add.h does not necessarily need to meet the header file name. #ifndef FOO123_YEP wil serve just as good as far as some foo maniac have not defined FOO123_YEP somewhere else :)

[S G H]

In fact, you should find an unused define.
Reason why you should try to have the file name inside the define.

Examples:
FOO_H_INCGUARD
FOO_H_DEF
FOO_HEADER

[ne555]

> http://stackoverflow.com/questions/1653958/why-are-ifndef-and-define-used-in-c-header-files
> That prevent double declaration of any identifiers such as types, enums and static variables.
which is not the case here, as you only have function declarations.