CODEWITHSUNDEEP
makefile
Thenewstockton
Thenewstockton

Reputation: 483

What is the archive target member name in makefile?

What is the target member name in an archive in a makefile?

It is explained here: https://www.gnu.org/software/make/manual/html_node/Archive-Members.html#Archive-Members but I don't quite understand it since there's not a brief example.

If I have 

target(name): name
       echo $%

$% is the automatic variable for target name.

If I use make target, this won't run

why? What is "target member name" actually?

Upvotes: 2

Views: 2308

Answers (1)

tripleee
tripleee

Reputation: 189789

The documentation you link to specifically explains this, near the beginning.

This construct is available only in targets and prerequisites, not in recipes! Most programs that you might use in recipes do not support this syntax and cannot act directly on archive members. Only ar and other programs specifically designed to operate on archives can do so. Therefore, valid recipes to update an archive member target probably must use ar.

So for example, to create an ar archive called target containing name, the commands would be

touch name
ar cr target name

As a Makefile, this is

target: name
    ar cr $@ $^

name:
    touch name

The target(name) syntax is useful when you want to manipulate the copy of name which is inside target. For example, if name was rebuilt at some point, your Makefile might want to compare its date stamp against the date stamp of the name member within target, to decide whether you need to update the copy inside target.

target(name): name
    ar cr $@ $%

But this doesn't specify how to create target in the first place; as far as I can tell, you need a recipe like the one at the top of my example for that.

Upvotes: 1

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