What does this strange Makefile target “.PHONY” mean

make

In this https://github.com/kubernetes/helm/blob/master/Makefile
there are targets with a dot in front of them. What is this convention for ?

.PHONY: all
all: build

.PHONY: build
build:
    GOBIN=$(BINDIR) $(GO) install $(GOFLAGS) -tags '$(TAGS)' -ldflags '$(LDFLAGS)' k8s.io/helm/cmd/...

Best Answer

The special rule .PHONY is used to specify that the target is not a file. Common uses are clean and all. This way it won't conflict if you have files named clean or all.

Here is a link to a section on this topic in the GNU make manual

Related Solutions

How to list all targets in make

This is how the bash completion module for make gets its list:

make -qp |
    awk -F':' '/^[a-zA-Z0-9][^$#\/\t=]*:([^=]|$)/ {split($1,A,/ /);for(i in A)print A[i]}' |
    sort -u

It prints out a newline-delimited list of targets, without paging.

What does % symbol in Makefile mean

Both expression specify all the files.

Nope, the first rule tells make how to obtain an .o file given the corresponding .c file. Note the singular: a single file.

The second rule (claims to) tell make how to obtain a bunch of .o files, given another bunch of corresponding .c files. Note the plural: all .c files resulting from the *.c globbing.

On a side note, %.o: %c is a GNU extension.

On another side note, you won't be learning how to use make on StackOverflow. You should consider reading a book instead.

Best Answer

Related Solutions

How to list all targets in make

What does % symbol in Makefile mean

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