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	Separate out the command execution part of if_changed, as we did
for if_changed_dep.
This allows us to reuse it in if_changed_rule.
  define rule_foo
          $(call cmd_and_savecmd,foo)
          $(call cmd,bar)
  endef
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
		
	
			
		
			
				
	
	
		
			210 lines
		
	
	
	
		
			7.5 KiB
		
	
	
	
		
			Text
		
	
	
	
	
	
			
		
		
	
	
			210 lines
		
	
	
	
		
			7.5 KiB
		
	
	
	
		
			Text
		
	
	
	
	
	
# SPDX-License-Identifier: GPL-2.0
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####
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# kbuild: Generic definitions
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# Convenient variables
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comma   := ,
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quote   := "
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squote  := '
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empty   :=
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space   := $(empty) $(empty)
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space_escape := _-_SPACE_-_
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pound := \#
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###
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# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
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dot-target = $(dir $@).$(notdir $@)
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###
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# Name of target with a '.tmp_' as filename prefix. foo/bar.o => foo/.tmp_bar.o
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tmp-target = $(dir $@).tmp_$(notdir $@)
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###
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# The temporary file to save gcc -MMD generated dependencies must not
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# contain a comma
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depfile = $(subst $(comma),_,$(dot-target).d)
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###
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# filename of target with directory and extension stripped
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basetarget = $(basename $(notdir $@))
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###
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# real prerequisites without phony targets
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real-prereqs = $(filter-out $(PHONY), $^)
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###
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# Escape single quote for use in echo statements
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escsq = $(subst $(squote),'\$(squote)',$1)
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###
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# Quote a string to pass it to C files. foo => '"foo"'
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stringify = $(squote)$(quote)$1$(quote)$(squote)
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###
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# Easy method for doing a status message
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       kecho := :
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 quiet_kecho := echo
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silent_kecho := :
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kecho := $($(quiet)kecho)
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###
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# filechk is used to check if the content of a generated file is updated.
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# Sample usage:
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#
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# filechk_sample = echo $(KERNELRELEASE)
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# version.h: FORCE
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#	$(call filechk,sample)
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#
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# The rule defined shall write to stdout the content of the new file.
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# The existing file will be compared with the new one.
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# - If no file exist it is created
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# - If the content differ the new file is used
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# - If they are equal no change, and no timestamp update
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define filechk
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	$(check-FORCE)
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	$(Q)set -e;						\
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	mkdir -p $(dir $@);					\
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	trap "rm -f $(dot-target).tmp" EXIT;			\
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	{ $(filechk_$(1)); } > $(dot-target).tmp;		\
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	if [ ! -r $@ ] || ! cmp -s $@ $(dot-target).tmp; then	\
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		$(kecho) '  UPD     $@';			\
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		mv -f $(dot-target).tmp $@;			\
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	fi
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endef
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###
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# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
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# Usage:
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# $(Q)$(MAKE) $(build)=dir
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build := -f $(srctree)/scripts/Makefile.build obj
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###
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# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
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# Usage:
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# $(Q)$(MAKE) $(dtbinst)=dir
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dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj
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###
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# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
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# Usage:
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# $(Q)$(MAKE) $(clean)=dir
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clean := -f $(srctree)/scripts/Makefile.clean obj
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# echo command.
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# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
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echo-cmd = $(if $($(quiet)cmd_$(1)),\
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	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
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# sink stdout for 'make -s'
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       redirect :=
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 quiet_redirect :=
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silent_redirect := exec >/dev/null;
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# printing commands
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cmd = @set -e; $(echo-cmd) $($(quiet)redirect) $(cmd_$(1))
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###
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# if_changed      - execute command if any prerequisite is newer than
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#                   target, or command line has changed
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# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
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#                   including used config symbols
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# if_changed_rule - as if_changed but execute rule instead
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# See Documentation/kbuild/makefiles.rst for more info
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ifneq ($(KBUILD_NOCMDDEP),1)
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# Check if both commands are the same including their order. Result is empty
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# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
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cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
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                         $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
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else
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cmd-check = $(if $(strip $(cmd_$@)),,1)
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endif
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# Replace >$< with >$$< to preserve $ when reloading the .cmd file
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# (needed for make)
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# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
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# (needed for make)
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# Replace >'< with >'\''< to be able to enclose the whole string in '...'
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# (needed for the shell)
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make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
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# Find any prerequisites that are newer than target or that do not exist.
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# (This is not true for now; $? should contain any non-existent prerequisites,
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# but it does not work as expected when .SECONDARY is present. This seems a bug
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# of GNU Make.)
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# PHONY targets skipped in both cases.
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newer-prereqs = $(filter-out $(PHONY),$?)
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# It is a typical mistake to forget the FORCE prerequisite. Check it here so
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# no more breakage will slip in.
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check-FORCE = $(if $(filter FORCE, $^),,$(warning FORCE prerequisite is missing))
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if-changed-cond = $(newer-prereqs)$(cmd-check)$(check-FORCE)
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# Execute command if command has changed or prerequisite(s) are updated.
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if_changed = $(if $(if-changed-cond),$(cmd_and_savecmd),@:)
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cmd_and_savecmd =                                                            \
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	$(cmd);                                                              \
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	printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd
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# Execute the command and also postprocess generated .d dependencies file.
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if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:)
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cmd_and_fixdep =                                                             \
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	$(cmd);                                                              \
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	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
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	rm -f $(depfile)
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# Usage: $(call if_changed_rule,foo)
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# Will check if $(cmd_foo) or any of the prerequisites changed,
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# and if so will execute $(rule_foo).
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if_changed_rule = $(if $(if-changed-cond),$(rule_$(1)),@:)
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###
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# why - tell why a target got built
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#       enabled by make V=2
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#       Output (listed in the order they are checked):
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#          (1) - due to target is PHONY
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#          (2) - due to target missing
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#          (3) - due to: file1.h file2.h
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#          (4) - due to command line change
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#          (5) - due to missing .cmd file
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#          (6) - due to target not in $(targets)
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# (1) PHONY targets are always build
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# (2) No target, so we better build it
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# (3) Prerequisite is newer than target
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# (4) The command line stored in the file named dir/.target.cmd
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#     differed from actual command line. This happens when compiler
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#     options changes
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# (5) No dir/.target.cmd file (used to store command line)
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# (6) No dir/.target.cmd file and target not listed in $(targets)
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#     This is a good hint that there is a bug in the kbuild file
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ifeq ($(KBUILD_VERBOSE),2)
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why =                                                                        \
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    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
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        $(if $(wildcard $@),                                                 \
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            $(if $(newer-prereqs),- due to: $(newer-prereqs),                \
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                $(if $(cmd-check),                                           \
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                    $(if $(cmd_$@),- due to command line change,             \
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                        $(if $(filter $@, $(targets)),                       \
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                            - due to missing .cmd file,                      \
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                            - due to $(notdir $@) not in $$(targets)         \
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                         )                                                   \
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                     )                                                       \
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                 )                                                           \
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             ),                                                              \
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             - due to target missing                                         \
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         )                                                                   \
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     )
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echo-why = $(call escsq, $(strip $(why)))
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endif
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###############################################################################
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# delete partially updated (i.e. corrupted) files on error
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.DELETE_ON_ERROR:
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# do not delete intermediate files automatically
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.SECONDARY:
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