explain caveat about use of numeric constants in podoc for sysopen()

	Message-Id: <199808041709.NAA01750@mks.com>
	Subject: Re: [PATCH] 5.005_01: OE MVS

p4raw-id: //depot/maint-5.005/perl@1731

diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index 69dd5aa..39b0944 100644 (file)
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -3828,8 +3828,11 @@ FILENAME, MODE, PERMS.
 
 The possible values and flag bits of the MODE parameter are
 system-dependent; they are available via the standard module C<Fcntl>.
-However, for historical reasons, some values are universal: zero means
-read-only, one means write-only, and two means read/write.
+For historical reasons, some values work on almost every system
+supported by perl: zero means read-only, one means write-only, and two
+means read/write.  We know that these values do I<not> work under
+OS/390 Unix and on the Macintosh; you probably don't want to use them
+in new code.
 
 If the file named by FILENAME does not exist and the C<open()> call creates
 it (typically because MODE includes the C<O_CREAT> flag), then the value of