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Chapter 11: Using make to Update Archive Files 129

11 Using make to Update Archive Files

Archive ﬁles are ﬁles containing named sub-ﬁles called members; they are maintained with

the program ar and their main use is as subroutine libraries for linking.

11.1 Archive Members as Targets

An individual member of an archive ﬁle can be used as a target or prerequisite in make.

You specify the member named member in archive ﬁle archive as follows:

archive(member)

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. For

example, this rule says to create a member hack.o in archive foolib by copying the ﬁle

hack.o:

foolib(hack.o) : hack.o

ar cr foolib hack.o

In fact, nearly all archive member targets are updated in just this way and there is an

implicit rule to do it for you. Please note: The ‘c’ ﬂag to ar is required if the archive ﬁle

does not already exist.

To specify several members in the same archive, you can write all the member names

together between the parentheses. For example:

foolib(hack.o kludge.o)

is equivalent to:

foolib(hack.o) foolib(kludge.o)

You can also use shell-style wildcards in an archive member reference. See Section 4.3

[Using Wildcard Characters in File Names], page 23. For example, ‘foolib(*.o)’ ex-

pands to all existing members of the foolib archive whose names end in ‘.o’; perhaps

‘foolib(hack.o) foolib(kludge.o)’.

11.2 Implicit Rule for Archive Member Targets

Recall that a target that looks like a(m) stands for the member named m in the archive ﬁle

When make looks for an implicit rule for such a target, as a special feature it considers

implicit rules that match (m), as well as those that match the actual target a(m).

This causes one special rule whose target is (%) to match. This rule updates the target

a(m) by copying the ﬁle m into the archive. For example, it will update the archive member

target foo.a(bar.o) by copying the ﬁle bar.o into the archive foo.a as a member named

bar.o.

When this rule is chained with others, the result is very powerful. Thus, ‘make

"foo.a(bar.o)"’ (the quotes are needed to protect the ‘(’ and ‘)’ from being interpreted

specially by the shell) in the presence of a ﬁle bar.c is enough to cause the following

recipe to be run, even without a makeﬁle:

1 2 ... 134 135 136 137 138 139 140 141 142 143 144 ... 211 212

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Roland Ver. 4.5 Technical Information Seite 139