How to split this c file up in .c and .h ?

[Louise Hoffman]

Dear readers,

I can't figure out how to split this file up into a .c and a .h file.
Can someone explain to me, what should go where?

Lots of love,
Louise =)

#ifndef FILE_NAME
#define FILE_NAME "ovn.sim"
#endif

struct sized_array_struct {
int n;
double *x;
double *y;
};

typedef struct sized_array_struct raw_t;

raw_t read_file() {

// lots of code here
}

 

[Zero]

Header file (declarations, typedefs)...

#ifndef FILE_NAME
#define FILE_NAME "ovn.sim"
#endif

struct sized_array_struct {
int n;
double *x;
double *y;

};

typedef struct sized_array_struct raw_t;

raw_t read_file(void);

Module:

Implementation of functions:
raw_t read_file(void)
{
// lots of code
}

Zeh Mau

 

[Zero]

.... and do not miss the include of the header file in the module...


Zeh Mau

 

[Louise Hoffman]

... and do not miss the include of the header file in the module...

Thank you so much! Your the best! =)

Hugs,
Louise =)

 

[Ben Bacarisse]

I can't figure out how to split this file up into a .c and a .h file.
Can someone explain to me, what should go where?

That is not easy to answer since it depends in part on what you doing
(in particular what port of the code need to know what things). For
example, I can't tell if the define of FILE_NAME is needed by the code
that uses read_file, or by the code that implements read_file or by
both.

Here is one possible way:

----- in file sized_array.h -----
#ifndef H_SIZED_ARRAY
#define H_SIZED_ARRAY

struct sized_array_struct {
int n;
double *x;
double *y;
};

typedef struct sized_array_struct raw_t;

raw_t read_file(void);
#endif
---------------------------------

The last-but-one line is a declaration (and a prototype) for the function
provided by the sized_array code. When a function takes no arguments,
it is better to state that explicitly with as I have done here (and below).

The lines at the top and the matching endif are an include guard -- an
optional extra that permits on to be more carefree about how this file
in included into others since its content can never be included twice.

----- in file sized_array.c -----
#include "sized_array.h"

#ifndef FILE_NAME
#define FILE_NAME "ovn.sim"
#endif

raw_t read_file(void) {

// lots of code here
}

 

[Louise Hoffman]

The last-but-one line is a declaration (and a prototype) for the function

provided by the sized_array code.  When a function takes no arguments,
it is better to state that explicitly with as I have done here (and below).
Noted.

The lines at the top and the matching endif are an include guard -- an
optional extra that permits on to be more carefree about how this file
in included into others since its content can never be included twice.

I like this include guard. Thanks =)

Hugs,
Louise

 

[CBFalconer]

I can't figure out how to split this file up into a .c and a .h
file. Can someone explain to me, what should go where?

Wrong question. You are writing a C file. You want other source
files to be able to access functions and variables (and possibly
more) from that C file. Put the function prototypes in the .h
file. Put extrn qualified definitions of the variables in the .h
file.

 

[Andrew Smallshaw]

It is a very bad idea to put definitions of any kind (other than
type definitions) into a header ...

and macros.

 

[CBFalconer]

CBFalconer said:
.... snip ...

^^^^^^^^^^^^^^^^^^^^^^^^^^^

It is a very bad idea to put definitions of any kind (other than
type definitions) into a header (except in cases where the header
is included only by exactly one source file; in such cases, whether
the existence of the header itself is wise is a matter of opinion).

Unless you want to replace 'definition' with 'declaration'.