How should I create files for different functions?

[junjun]

Hi, I need some help with this question.

I am writing a main functions, with MACRO and global variables, and lots of supporting functions a(), b(), c(),........z() that are called by main function and also use the MACRO and global variables too. In order to avoid the mess to put all of them in main.c, I am thinking of creating other files for different functions.

I think I am trying to express is how to partition functions to differnt c files.
Is there any suggestion how to do that?

Thanks a lot for your help!

JJ

[Savage]

Hi, I need some help with this question.

I am writing a main functions, with MACRO and global variables, and lots of supporting functions a(), b(), c(),........z() that are called by main function and also use the MACRO and global variables too. In order to avoid the mess to put all of them in main.c, I am thinking of creating other files for different functions.

I think I am trying to express is how to partition functions to different c files.
Is there any suggestion how to do that?

Thanks a lot for your help!

JJ

If I understood you well,then you will be able to this by using bunch of different header files.In a header file you store function declaration and definition and then in main you just include that file.

e.g #include "FunctionA.h"

Savage

[weaknessforcats]

I am writing a main functions, with MACRO and global variables,

Please don't do that. You are building a disaster model. I got to work on a systme like this one time. There were 380 programs and all of the variables were global. Every function has no arguments. Because of that, the ability to change the system went to zero since you would have to review every function in every program every time for every change.

To avoid this, programmers just added new global variables to avoid trouble by changing the existing ones.

There is no reason for a global variable:
1) local variable hides global variable of the same name
2) name conflicts. even within namespaces.
3) exposes implementation. No redesign
4) causes race conditions in multithreaded programs
5) expands ripple when value is screwed up. every function is a suspect
6) no guarantee the user will use global
7) expands program footprint
8) memory for globals may be limited
9) no guarantee for the order of creation. Only the globals in a single file are crerated in the order of declaration. The total order is indeterminate. Hence, your global may no be there when you need it. Especially if a global object needs a global variable in another file in its constructor. aka: the initialization fiasco
10) expands ripple when a recode is needed. All the code using globals has to be changed. N=Bad if there is a large installed base.

[kreagan]

There is no reason for a global variable:

Weaknessforcats definately has a point. Though, I use static global variables sparingly. This forces the variable to be only accessable to the .c file which contains it. (However, I just started working ... so lets see if this opinion changes. lol. )

If your desire is not to declare a lot of variables per function, look into Structs.

If you have a lot of variables that will not change, I suggest using #defines for constants.

Use macros and GOTOs sparingly.

[junjun]

Thanks a lot for all your help.

I think this problem links to a lot of the behavior of the compiler. And I have checked a few references last night.

Basically,

the declarations of functions struct and #define stuff will be in the header file,

but the variable will use "extern ".

Does anyone knows about why we need to include .h file in the implementation .c file, cause we don't need a declaration while we already have the defintion.

Kind of just curious!

Thanks!

[weaknessforcats]

Basically,

the declarations of functions struct and #define stuff will be in the header file,

but the variable will use "extern ".

Does anyone knows about why we need to include .h file in the implementation .c file, cause we don't need a declaration while we already have the defintion.

If you are referring to extern, then that is a declaration.

If you are referring to defining a global variable in a .c file, then you do not need the extern to that variable in that file.

I hope you read my Post #3 before you proceed. Just remember that two years from now when you need to change your design in a way that changes the global variables, you will ned to rework your entire body of code. And, of course, you cannot be multi-threaded with global variables.