linux - what is meaning of export in multiple-line variable -
what meaning of export
in multiple-line variable?
in example command export foo
or not, output 'welcome'.
define foo echo welcome endef export foo all: @$(foo)
variable values of top-level make
can passed sub-make
(sub directory makefile) through environment explicit request. these variables defined in sub-make defaults.
the special variables shell , makeflags exported (unless unexport them).
if want export specific variables sub-make, use export directive, this:
export variable
if want prevent variable being exported, use unexport directive, this:
unexport variable
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