file writable name
Returns 1 if file name is writable by the current user, 0 otherwise.
RS just noticed that from Windows 2000 over network boundaries, it may report 1 even for directories where I positively may not write. A hacky workaround seems to be:
set dummyname $name.[clock seconds] ;# not to clobber an existing one
if { [catch {file open $dummyname w]} fp] } {
# not writable
} else {
close $fp
file delete $dummyname
}EL confirms this, and notices that the converse is also true: 0 is being returned where I do have permission to write. Also for regular files, [file writable] is unreliable across network boundaries. Richard's hack might be extended to:
rename file _file
proc file {args} {
if {[string match [lindex $args 0]* writable]} {
set name [lindex $args 1]
if {[file isdirectory $name]} {
set fileName [file join $name writabletest.dummy]
set isdir 1
} elseif {[file exists $name]} {
set fileName $name
set isdir 0
} else {
return 0
}
if {[catch {open $fileName w} fp]} {
# not writable
return 0
} else {
close $fp
if {$isdir} {
file delete $fileName
}
return 1
}
} else {
eval _file $args
}
}Vince adds --- 'NativeAccess' in tclWinFile.c needs updating to deal with Windows user/permission-related information (whatever that is -- anyone have any pointers?).
EL would TWAPI be of use here?
See also:
Tcl syntax help - Category Command - Category Introspection - Category File