Change 11961 by jhi@alpha on 2001/09/09 13:34:12
perlport additions: 1 while unlink, add/delete directory
entries and permissions, cygwin stat funkiness (from Michael
Schwern and Nicholas Clark)
Affected files ...
... //depot/perl/pod/perlport.pod#70 edit
Differences ...
==== //depot/perl/pod/perlport.pod#70 (text) ====
Index: perl/pod/perlport.pod
--- perl/pod/perlport.pod.~1~ Sun Sep 9 07:45:06 2001
+++ perl/pod/perlport.pod Sun Sep 9 07:45:06 2001
@@ -352,6 +352,25 @@
Don't open the same file more than once at a time for writing, as some
operating systems put mandatory locks on such files.
+Don't assume that write/modify permission on a directory gives the
+right to add or delete files/directories in that directory. That is
+filesystem specific: in some filesystems you need write/modify
+permission also (or even just) in the file/directory itself. In some
+filesystems (AFS, DFS) the permission to add/delete directory entries
+is a completely separate permission.
+
+Don't assume that a single C<unlink> completely gets rid of the file:
+some filesystems (most notably the ones in VMS) have versioned
+filesystems, and unlink() removes only the most recent one (it doesn't
+remove all the versions because by default the native tools on those
+platforms remove just the most recent version, too). The portable
+idiom to remove all the versions of a file is
+
+ 1 while unlink "file" or die $!;
+
+This will terminate if the file is undeleteable for some reason
+(protected, not there, and so on).
+
Don't count on a specific environment variable existing in C<%ENV>.
Don't count on C<%ENV> entries being case-sensitive, or even
case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
@@ -1702,6 +1721,9 @@
dev, rdev, blksize, and blocks are not available. inode is not
meaningful and will differ between stat calls on the same file. (os2)
+some versions of cygwin when doing a stat("foo") and if not finding it
+may then attempt to stat("foo.exe") (Cygwin)
+
=item symlink OLDFILE,NEWFILE
Not implemented. (Win32, VMS, S<RISC OS>)
End of Patch.
