Error analysis of receive comments before first target. Stop

Today, make an example of using the make file, install the operation and write the file. This error occurred using ‘make – F makefile1’.

recipe commences before first target.  Stop

The content of makefile1 is also very simple

[tab]3.o: 3.c b.h c.h

[tab][tab]gcc -c 3.c

Later, it was found that the [tab] in the first line needed to be deleted, and the command passed.

3.o: 3.c b.h c.h

[tab][tab]gcc -c 3.c

There is a very regrettable syntax phenomenon in makefile: there is a difference between control and tab. The line of the rule must start with a tab, not a space.