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34 GNU make

.EXPORT_ALL_VARIABLES

Simply by being mentioned as a target, this tells make to export all variables

to child processes by default. See Section 5.7.2 [Communicating Variables to a

Sub-make], page 52.

.NOTPARALLEL

If .NOTPARALLEL is mentioned as a target, then this invocation of make will

be run serially, even if the ‘-j’ option is given. Any recursively invoked make

command will still run recipes in parallel (unless its makeﬁle also contains this

target). Any prerequisites on this target are ignored.

.ONESHELL

If .ONESHELL is mentioned as a target, then when a target is built all lines of

the recipe will be given to a single invocation of the shell rather than each line

being invoked separately (see Section 5.3 [Recipe Execution], page 44).

.POSIX

If .POSIX is mentioned as a target, then the makeﬁle will be parsed and run

in POSIX-conforming mode. This does not mean that only POSIX-conforming

makeﬁles will be accepted: all advanced GNU make features are still available.

Rather, this target causes make to behave as required by POSIX in those areas

where make’s default behavior diﬀers.

In particular, if this target is mentioned then recipes will be invoked as if the

shell had been passed the -e ﬂag: the ﬁrst failing command in a recipe will

cause the recipe to fail immediately.

Any deﬁned implicit rule suﬃx also counts as a special target if it appears as a target,

and so does the concatenation of two suﬃxes, such as ‘.c.o’. These targets are suﬃx rules,

an obsolete way of deﬁning implicit rules (but a way still widely used). In principle, any

target name could be special in this way if you break it in two and add both pieces to the

suﬃx list. In practice, suﬃxes normally begin with ‘.’, so these special target names also

begin with ‘.’. See Section 10.7 [Old-Fashioned Suﬃx Rules], page 125.

4.9 Multiple Targets in a Rule

A rule with multiple targets is equivalent to writing many rules, each with one target, and

all identical aside from that. The same recipe applies to all the targets, but its eﬀect may

vary because you can substitute the actual target name into the recipe using ‘$@’. The rule

contributes the same prerequisites to all the targets also.

This is useful in two cases.

• You want just prerequisites, no recipe. For example:

kbd.o command.o files.o: command.h

gives an additional prerequisite to each of the three object ﬁles mentioned.

• Similar recipes work for all the targets. The recipes do not need to be absolutely

identical, since the automatic variable ‘$@’ can be used to substitute the particular

target to be remade into the commands (see Section 10.5.3 [Automatic Variables],

page 120). For example:

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Roland Ver. 4.5 Technical Information Seite 44