+sub rename_link_xf ($$$) {
+ # renames/moves or links/copies $src to $dst,
+ # even if $dst is on a different fs
+ # (May use the filename "$dst.tmp".);
+ # On success, returns true.
+ # On failure, returns false and sets
+ # $@ to a reason message
+ # $! to an errno value, or -1 if not known
+ # having possibly printed something about mv to stderr.
+ my ($keeporig,$src,$dst) = @_;
+ if ($keeporig
+ ? link $src, $dst
+ : rename $src, $dst) {
+ return 1;
+ } elsif ($! != EXDEV) {
+ $@ = "$!";
+ return 0;
+ }
+ $!=0; $?=0;
+ my @cmd = ($keeporig ? qw(cp) : qw(mv));
+ push @cmd, (qw(--), $src, "$dst.tmp");
+ debugcmd '+',@cmd;
+ if (system @cmd) {
+ failedcmd_report_cmd undef, @cmd;
+ $@ = failedcmd_waitstatus();
+ $! = -1;
+ return 0;
+ }
+ if (rename "$dst.tmp", $dst) {
+ return 1;
+ } else {
+ $@ = f_ "finally install file after mv: %S", $!;
+ return 0;
+ }
+}
+