Gnu make - implicit rule 概念

預設你在makefile內不編輯rule的話
gnu make會根據你所定義的target and prerequisites作自動編輯

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以此範例說明
解壓縮完
下make

nelsonchung@nelsonchung-aspireone:~/ebooks/gnumake/DoTest$ make
gcc -c main.c
gcc -c Eye.c
gcc -c Nose.c
gcc -c Ear.c
gcc -c Mouse.c
cc    -c -o Face.o Face.c
gcc main.o Eye.o Nose.o Ear.o Mouse.o -o main
nelsonchung@nelsonchung-aspireone:~/ebooks/gnumake/DoTest$

藍色部份

因為在makefile裡面沒有特地去寫rule

nelsonchung@nelsonchung-aspireone:~/ebooks/gnumake/DoTest$ cat makefile

all: main.o Eye.o Nose.o Ear.o Mouse.o Face.o

gcc main.o Eye.o Nose.o Ear.o Mouse.o -o main

main.o: main.c

gcc -c main.c

Eye.o: Eye.h

gcc -c Eye.c

Nose.o: Nose.h

gcc -c Nose.c

Ear.o: Ear.h

gcc -c Ear.c

Mouse.o: Mouse.h

gcc -c Mouse.c

Face.o: Face.c

clean:

rm main.o Eye.o Nose.o Ear.o Mouse.o Face.o main

所以gnu make會根據你現在要編譯的是.c, .cpp, .p or other files去啟動相對應的compiler

Reference:

Gnu make 文件第十章

10 Using Implicit Rules