z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

make
targets :– prereqs
Clears the previous list of prerequisites before adding the new
prerequisites.
targets :: prereqs
If no prerequisites are specified, the targets are always remade. Otherwise
it is used for multiple rules applying to the same targets. Each rule can
specify a different set of prerequisites with a different recipe for updating the
target. Each rule is treated independently; the target is remade for each rule
with recently changed prerequisites, using the corresponding recipe.
targets :| prereqs
Can only be used in metarules. It tells make to treat each metadependency
as an independent rule. For example:
%$0 :| archive/%.c rcs/%.c /srcarc/RCS/%period.c
recipe...
is equivalent to
%$0 : archive/$.c
recipe:
%$0 : rcs/%.c
recipe:
%$0 : /srcarc/rcs/%.c
recipe:
Circular Dependencies
There are two types of circular dependencies: within-rule and between-rule.
Recipes
A within-rule circular dependency occurs when the target’s name is included in the
list of prerequisites for that target. For example,
c.o : a.o b.o c.o
is a within-rule circular dependency. make detects a within-rule circular dependency
when it is parsing the makefile to build the dependency tree.
A between-rule circular dependency occurs when you have two targets, each of
which includes the other’s name in its prerequisite list. For example,
a.o : b:o
b:o : a.o
is a between-rules circular dependency. make detects a between-rule circular
dependency when it is processing the dependency tree built during the parse
phase.
Normally make only detects circular dependencies for those targets actually being
built. When a circular dependency is encountered, make issues a warning
message, removes the offending prerequisite from the list, and continues parsing
the makefile. You can use the .CYCLECHECK special target to alter. make’s treatment
of circular dependencies. See also “Special Target Directives” on page 404, which
describes special targets.)
You can use a target that has prerequisites but no recipes to add the given
prerequisites to that target’s list of prerequisites.
398 z/OS V1R9.0 UNIX System Services Command Reference