Change 18297 by jhi@lyta on 2002/12/12 19:19:56
Warn about the non-portabilities of strftime.
Affected files ...
... //depot/maint-5.8/perl/ext/POSIX/POSIX.pod#4 edit
Differences ...
==== //depot/maint-5.8/perl/ext/POSIX/POSIX.pod#4 (text) ====
Index: perl/ext/POSIX/POSIX.pod
--- perl/ext/POSIX/POSIX.pod#3~18294~ Thu Dec 12 06:34:58 2002
+++ perl/ext/POSIX/POSIX.pod Thu Dec 12 11:19:56 2002
@@ -1251,12 +1251,23 @@
year (C<year>) is given in years since 1900. I.e., the year 1995 is 95; the
year 2001 is 101. Consult your system's C<strftime()> manpage for details
about these and the other arguments.
+
If you want your code to be portable, your format (C<fmt>) argument
should use only the conversion specifiers defined by the ANSI C
-standard. These are C<aAbBcdHIjmMpSUwWxXyYZ%>.
-The given arguments are made consistent
-as though by calling C<mktime()> before calling your system's
-C<strftime()> function, except that the C<isdst> value is not affected.
+standard (C89, to play safe). These are C<aAbBcdHIjmMpSUwWxXyYZ%>.
+But even then, the B<results> of some of the conversion specifiers are
+non-portable. For example, the specifiers C<aAbBcpZ> change according
+to the locale settings of the user, and both how to set locales (the
+locale names) and what output to expect are non-standard.
+The specifier C<c> changes according to the timezone settings of the
+user and the timezone computation rules of the operating system.
+The C<Z> specifier is notoriously unportable since the names of
+timezones are non-standard. Sticking to the numeric specifiers is the
+safest route.
+
+The given arguments are made consistent as though by calling
+C<mktime()> before calling your system's C<strftime()> function,
+except that the C<isdst> value is not affected.
The string for Tuesday, December 12, 1995.
End of Patch.
