directive-export.mk revision 1.10 1 # $NetBSD: directive-export.mk,v 1.10 2023/11/19 09:45:19 rillig Exp $
2 #
3 # Tests for the .export directive.
4 #
5 # See also:
6 # directive-misspellings.mk
7
8 # TODO: Implementation
9
10 INDIRECT= indirect
11 VAR= value $$ ${INDIRECT}
12
13 # Before 2020-12-13, this unusual expression invoked undefined behavior since
14 # it accessed out-of-bounds memory via Var_Export -> ExportVar -> MayExport.
15 .export ${:U }
16
17 # A variable is exported using the .export directive.
18 # During that, its value is expanded, just like almost everywhere else.
19 .export VAR
20 .if ${:!env | grep '^VAR'!} != "VAR=value \$ indirect"
21 . error
22 .endif
23
24 # Undefining a variable that has been exported implicitly removes it from
25 # the environment of all child processes.
26 .undef VAR
27 .if ${:!env | grep '^VAR' || true!} != ""
28 . error
29 .endif
30
31 # No syntactical argument means to export all variables.
32 .export
33
34 # An empty argument means no additional variables to export.
35 .export ${:U}
36
37
38 # Before a child process is started, whether for the '!=' assignment operator
39 # or for the ':sh' modifier, all variables that were marked for being exported
40 # are expanded and then exported. If expanding such a variable requires
41 # running a child command, the marked-as-exported variables would need to be
42 # exported first, ending in an endless loop. To avoid this endless loop,
43 # don't export the variables while preparing a child process, see
44 # ExportVarEnv.
45 EMPTY_SHELL= ${:sh}
46 .export EMPTY_SHELL # only marked for export at this point
47 _!= :;: # Force the variable to be actually exported.
48
49
50 # If the '.export' directive exports a variable whose value contains a '$',
51 # the actual export action is deferred until a subprocess is started, assuming
52 # that only subprocesses access the environment variables. The ':localtime'
53 # modifier depends on the 'TZ' environment variable, without any subprocess.
54 export TZ=${UTC}
55 # expect+1: 00:00:00
56 .info ${%T:L:localtime=86400}
57 INDIRECT_TZ= ${:UAmerica/Los_Angeles}
58 TZ= ${INDIRECT_TZ}
59 .export TZ
60 # expect+1: 00:00:00
61 .info ${%T:L:localtime=86400}
62 _!= echo 'force exporting the environment variables'
63 # expect+1: 16:00:00
64 .info ${%T:L:localtime=86400}
65
66
67 all:
68