new to make... advice needed

pablowablo · 03-04-2005, 09:20 PM

Hello, I'm starting to learn make and I have some questions...

The following are my files and their dependencies:

main.c ---> depends on Menu.c Student.c List.c
Menu.c----> depends on Student.c List.c
Student.c--->depends on Menu.c
List.c ---> depends on nothing

my question is how do I create my makefile given the scenario?

This is what I came up with

Code:

SAS: main.o Menu.o List.o Student.o
	gcc main.o Menu.o List.o Student.o -o SAS

main.o: Menu.h Menu.c Student.h Student.c List.h List.c
	gcc  ??????????????
Menu.o: Menu.h Menu.c Student.h Student.c List.h List.c
	gcc ????????????????
Student.o: Student.h Student.c Menu.h Menu.c
	gcc ?????????????????
List.o: List.c List.h
	gcc List.c -o List.o

I'm a bit confused on the command I have to issue to compile the objects...

should it be like:
gcc Menu.c Student.c List.c -o main.o
gcc Menu.c Student.c List.c -o Menu.o
gcc Student.c Menu.c -o Student.o

???

I think it would work but I feel I'm missing something... reason is I don't think it utilizes the purpose of make in the first place..... or is this a problem with my dependencies itself?

thanks hope you can give me some advice

jtshaw · 03-04-2005, 10:06 PM

I wanna ask you about your dependencies real quick... how does the circular dependency come into play? If Menu depends on Student, and Student depends on Menu... Are you declaring things in headers and included them in your program?

johnMG · 03-04-2005, 10:54 PM

I'm a bit confused on the command I have to issue to compile the objects...

should it be like:
gcc Menu.c Student.c List.c -o main.o

No.

For your purposes here, it should be like

Code:

gcc -c Menu.c Student.c List.c

You don't need "-o Menu.o". The "-o" is mostly useful just for giving your executable a name. You want the "-c" so that a .o file is left behind, rather than gcc trying to link your .o file.

Next step for you is to learn how suffix rules work. :) But you don't need that for now.

pablowablo · 03-06-2005, 10:02 AM

Hello thanks for the reply... I modified my makefile like thiss:

Code:

SAS: Menu.o Student.o List.o
	gcc Menu.c Student.c List.c -o SAS

Menu.o: Menu.c Student.c List.c Menu.h Student.h List.h
	gcc -c Menu.c Student.c List.c

Student.o: Student.c List.c Student.h List.h
	gcc -c Student.c List.c

List.o: List.c List.h
	gcc -c List.c

It works, but I notice it's no different than compiling every source every time....

I think the problem is with my dependencies... When one gets edited, this has to get executed : gcc Menu.c Student.c List.c -o SAS...

or should my command be different? sorry I'm new with gcc...

Quote:

wanna ask you about your dependencies real quick... how does the circular dependency come into play? If Menu depends on Student, and Student depends on Menu... Are you declaring things in headers and included them in your program?

I do have the prototypes in header files and my code includes them...

Im, curious is there a possible scenario where circular dependencies causes errors?? Like how bout if a function uses a function that is in another source file and that function uses another function in the previous source file? Is this allowed?

Quote:

You don't need "-o Menu.o". The "-o" is mostly useful just for giving your executable a name. You want the "-c" so that a .o file is left behind, rather than gcc trying to link your .o file.

Next step for you is to learn how suffix rules work.

But you don't need that for now.

Thanks! I modified my makefile... Hmm don't think I have heard of suffix rules yet