+
+# The following rule is not designed to be portable,
+# and relies on tools that not everyone has.
+
+# Most functions in src/*.c should have static scope.
+# Any that don't must be marked with `extern', but `main'
+# and `usage' are exceptions. They're always extern, but
+# don't need to be marked.
+#
+# The second nm|grep checks for file-scope variables with `extern' scope.
+sc_tight_scope: $(all_programs)
+ @t=exceptions-$$$$; \
+ trap 's=$$?; rm -f $$t; exit $$s' 0 1 2 13 15; \
+ ( printf '^main$$\n^usage$$\n'; \
+ grep -h -A1 '^extern .*[^;]$$' $(SOURCES) \
+ | grep -vE '^(extern |--)' |sed 's/^/^/;s/ .*/$$/' ) > $$t; \
+ if nm -e *.$(OBJEXT) \
+ | sed -n 's/.* T //p' \
+ | grep -Ev -f $$t; then \
+ echo 'the above functions should have static scope' 1>&2; \
+ exit 1; \
+ fi; \
+ ( printf '^program_name$$\n'; \
+ sed -n 's/^extern .*[* ]\([a-zA-Z_][a-zA-Z_0-9]*\);$$/^\1$$/p' \
+ $$(ls $(SOURCES) | grep '\.h$$') /dev/null) > $$t; \
+ if nm -e *.$(OBJEXT) \
+ | sed -n 's/.* [BD] //p' \
+ | grep -Ev -f $$t; then \
+ echo 'the above variables should have static scope' 1>&2; \
+ exit 1; \
+ fi