this is bug?

[Рушан Секаев]

GNU Make 3.81
Ubuntu 12.04
3.8.0-44-generic

makefile

hello: main.c hello.c
    gcc -o hello main.o hello.o
main.o: main.c
    gcc -c -o main.o main.c
hello.o: hello.c
    gcc -c -o hello.o hello.c

if i update 'main.c' and run make hello then 'hello' file is not updated. Although the documentation is written on the contrary.

sorry for my english