Question

I have main.cpp (including main function) and func1.cpp, and I want to link these files with a makefile. Classic form would be:

main: main.o func1.o
    g++ main.o func1.o -o main
main.o: main.cpp
    g++ -c main.cpp
func1.o: func1.cpp
    g++ -c func1.cpp

or one can write

main: func1.o main.o 
    g++ main.o func1.o -o main
func1.o: func1.cpp
    g++ -c func1.cpp
main.o: main.cpp
    g++ -c main.cpp

or

main: main.o func1.o
    g++ main.o func1.o -o main
func1.o: func1.cpp
    g++ -c func1.cpp
main.o: main.cpp
    g++ -c main.cpp

Do the last two differ from the classic one ? Does one have some advantages over the other?

Answer 1

No, the only time the order of the rules comes into play is when you just enter make, in which case it can choose the first rule as the default.

Beyond that, make is intelligent enough to execute dependent rules no matter where they are in the file.