More porting notes about filesystems, AmigaOS, and MiNT.

p4raw-id: //depot/cfgperl@2500

1 files changed, 28 insertions, 4 deletions

diff --git a/pod/perlport.pod b/pod/perlport.pod
index 6faa0d0659..7a03c12998 100644
--- a/pod/perlport.pod
+++ b/pod/perlport.pod
@@ -175,7 +175,7 @@ transfer and store numbers always in text format, instead of raw
 binary, or consider using modules like C<Data::Dumper> (included in
 the standard distribution as of Perl 5.005) and C<Storable>.
 
-=head2 Files
+=head2 Files and Filesystems
 
 Most platforms these days structure files in a hierarchical fashion.
 So, it is reasonably safe to assume that any platform supports the
@@ -194,6 +194,14 @@ LPT:).
 
 S<Mac OS> uses C<:> as a path separator instead of C</>.
 
+The filesystem may not support neither hard links (C<link()>) nor
+symbolic links (C<symlink()>, C<readlink()>, C<lstat()>).
+
+The filesystem may not support neither access timestamp nor change
+timestamp (meaning that about the only portable timestamp is the
+modification timestamp), or one second granularity of any timestamps
+(e.g. the FAT filesystem limits the time granularity to two seconds).
+
 VOS perl can emulate Unix filenames with C</> as path separator.  The
 native pathname characters greater-than, less-than, number-sign, and
 percent-sign are always accepted.
@@ -252,8 +260,11 @@ Likewise, if using C<AutoSplit>, try to keep the split functions to
 make it so the resulting files have a unique (case-insensitively)
 first 8 characters.
 
-Don't assume C<E<gt>> won't be the first character of a filename.  Always
-use C<E<lt>> explicitly to open a file for reading.
+There certainly can be whitespace in filenames.  Many systems (DOS,
+VMS) cannot have more than one C<"."> in their filenames.
+
+Don't assume C<E<gt>> won't be the first character of a filename.
+Always use C<E<lt>> explicitly to open a file for reading.
 
     open(FILE, "<$existing_file") or die $!;
 
@@ -829,7 +840,7 @@ an effect on what happens with some perl functions (such as C<chr>,
 C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
 well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
 and C<|>, not to mention dealing with socket interfaces to ASCII computers
-(see L<Newlines>).
+(see L<"NEWLINES">).
 
 Fortunately, most web servers for the mainframe will correctly translate
 the C<\n> in the following statement to its ASCII equivalent (note that
@@ -1314,6 +1325,9 @@ method of spawning a process. (Win32)
 
 Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
 
+Link count not updated because hard links are not quite that hard
+(They are sort of half-way between hard and soft links). (AmigaOS)
+
 =item lstat FILEHANDLE
 
 =item lstat EXPR
@@ -1347,6 +1361,8 @@ open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
 
 Not implemented. (S<Mac OS>)
 
+Very limited functionality. (MiNT)
+
 =item readlink EXPR
 
 =item readlink
@@ -1444,6 +1460,11 @@ the child program uses a compatible version of the emulation library.
 I<scalar> will call the native command line direct and no such emulation
 of a child Unix program will exists.  Mileage B<will> vary.  (S<RISC OS>)
 
+Far from being POSIX compliant.  Because there may be no underlying
+/bin/sh tries to work around the problem by forking and execing the
+first token in its argument string.  Handles basic redirection ("<" or
+">") on its own behalf. (MiNT)
+
 =item times
 
 Only the first entry returned is nonzero. (S<Mac OS>)
@@ -1473,6 +1494,9 @@ should not be held open elsewhere. (Win32)
 
 Returns undef where unavailable, as of version 5.005.
 
+C<umask()> works but the correct permissions are only set when the file is
+finally close()d.
+
 =item utime LIST
 
 Only the modification time is updated. (S<Mac OS>, VMS, S<RISC OS>)