From: Abigail Date: Tue, 15 Aug 2000 20:12:41 +0000 (+0000) Subject: [ID 20000815.014] [PATCH] INSTALL doesn't mention 64 bit support. X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=9d5a2765247106c08687386ac3cf275028b5a54a;p=p5sagit%2Fp5-mst-13.2.git [ID 20000815.014] [PATCH] INSTALL doesn't mention 64 bit support. Message-Id: <20000815201241.25556.qmail@foad.org> p4raw-id: //depot/perl@6644 --- diff --git a/INSTALL b/INSTALL index 2b21edb..21eaa0a 100644 --- a/INSTALL +++ b/INSTALL @@ -670,6 +670,52 @@ or by Eventually (by perl v5.6.0) this internal confusion ought to disappear, and these options may disappear as well. +=head2 64 bit support. + +If your platform does not have 64 bits natively, but can simulate them with +compiler flags and/or C or C, you can build a perl that +uses 64 bits. + +There are actually two modes of 64-bitness: the first one is achieved +using Configure -Duse64bitint and the second one using Configure +-Duse64bitall. The difference is that the first one is minimal and +the second one maximal. The first works in more places than the second. + +The C does only as much as is required to get 64-bit +integers into Perl (this may mean, for example, using "long longs") +while your memory may still be limited to 2 gigabytes (because your +pointers could still be 32-bit). Note that the name C<64bitint> does +not imply that your C compiler will be using 64-bit Cs (it might, +but it doesn't have to): the C means that you will be +able to have 64 bits wide scalar values. + +The C goes all the way by attempting to switch also +integers (if it can), longs (and pointers) to being 64-bit. This may +create an even more binary incompatible Perl than -Duse64bitint: the +resulting executable may not run at all in a 32-bit box, or you may +have to reboot/reconfigure/rebuild your operating system to be 64-bit +aware. + +Natively 64-bit systems like Alpha and Cray need neither -Duse64bitint +nor -Duse64bitall. + + NOTE: 64-bit support is still experimental on most platforms. + Existing support only covers the LP64 data model. In particular, the + LLP64 data model is not yet supported. 64-bit libraries and system + APIs on many platforms have not stabilized--your mileage may vary. + +=head2 Long doubles + +In some systems you may be able to use long doubles to enhance the +range and precision of your double precision floating point numbers +(that is, Perl's numbers). Use Configure -Duselongdouble to enable +this support (if it is available). + +=head2 "more bits" + +You can "Configure -Dusemorebits" to turn on both the 64-bit support +and the long double support. + =head2 Selecting File IO mechanisms Previous versions of perl used the standard IO mechanisms as defined in