1 # $NetBSD: directive-export.mk,v 1.12 2024/06/01 10:06:23 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 # Before var.c 1.1117 from 2024-06-01, a plain ".export" without a syntactical 32 # argument exported all global variables. This case could be triggered 33 # unintentionally by writing a line of the form ".export ${VARNAMES}" to a 34 # makefile, when VARNAMES was an empty list. 35 # expect+1: warning: .export requires an argument. 36 .export 37 38 # An empty argument means no additional variables to export. 39 .export ${:U} 40 41 42 # Before a child process is started, whether for the '!=' assignment operator 43 # or for the ':sh' modifier, all variables that were marked for being exported 44 # are expanded and then exported. If expanding such a variable requires 45 # running a child command, the marked-as-exported variables would need to be 46 # exported first, ending in an endless loop. To avoid this endless loop, 47 # don't export the variables while preparing a child process, see 48 # ExportVarEnv. 49 EMPTY_SHELL= ${:sh} 50 .export EMPTY_SHELL # only marked for export at this point 51 _!= :;: # Force the variable to be actually exported. 52 53 54 # If the '.export' directive exports a variable whose value contains a '$', 55 # the actual export action is deferred until a subprocess is started, assuming 56 # that only subprocesses access the environment variables. The ':localtime' 57 # modifier depends on the 'TZ' environment variable, without any subprocess. 58 export TZ=${UTC} 59 # expect+1: 00:00:00 60 .info ${%T:L:localtime=86400} 61 INDIRECT_TZ= ${:UAmerica/Los_Angeles} 62 TZ= ${INDIRECT_TZ} 63 .export TZ 64 # expect+1: 00:00:00 65 .info ${%T:L:localtime=86400} 66 _!= echo 'force exporting the environment variables' 67 # expect+1: 16:00:00 68 .info ${%T:L:localtime=86400} 69 70 71 all: 72