$ perl_del = "delete"
$ pif = "if"
$! --- define i/o redirection (sys$output set by lib$spawn)
-$ pif perl_popen_in .nes. "" then perl_define sys$input 'perl_popen_in'
-$ pif perl_popen_err .nes. "" then perl_define sys$error 'perl_popen_err'
+$ pif perl_popen_in .nes. "" then perl_define/user/name_attributes=confine sys$input 'perl_popen_in'
+$ pif perl_popen_err .nes. "" then perl_define/user/name_attributes=confine sys$error 'perl_popen_err'
+$ pif perl_popen_out .nes. "" then perl_define sys$output 'perl_popen_out'
$ cmd = perl_popen_cmd
$! --- get rid of global symbols
$ perl_del/symbol/global perl_popen_in
$ perl_del/symbol/global perl_popen_err
+$ perl_del/symbol/global perl_popen_out
$ perl_del/symbol/global perl_popen_cmd
$ perl_on
$ 'cmd