Building object files that depends on other object files

EDITS: Including link to my makefile

I have a main program that calls a bunch of functions defined in other source files. This is not a problem because I am using cc -c functionSource.c ~~functionHeader.h~~ and generating object files before compiling my main program with cc main.c func1.o func2.o .... -o test.o

I am having problems when one of my functions depends on another function. For example: My main program calls an shuffle function which is defined in it's own source file and the shuffle function calls a swap function which in turn is defined in it's own source file.

When i try to generate the shuffle.o file for my main program using cc -c shuffle.o I get an undefined reference to swap error.

When I try to cc shuffle.c swap.o i get an undefined reference to main error.

Here is my makefile

~~How do I go about fixing this?~~ Found the problem. I had a swap function declared inside insertionSort.h and shuffle.h but no implementations.

Solution

Have a look to the man page: '-c' makes the compiler generating object files only (not trying to link).

Do the following:

cc -c insertionSort.c     # => gives insertionSort.o
cc -c -c functionSource.c # => gives functionSource.o
cc insertionSort.o functionSource.o ...and-so-on... main.c -o test

It's not necessary to specify header files - it doesn't help.

BTW: If you have mor than one implementation file, it is rather useful

(a) to learn make
(b) stick to the convention that object files and programs should be named like th sources.

E.g:

foo.c => foo.o
bar.c => bar

etc - you get the picture.