@c Copyright (C) 1999-2004 Free Software Foundation, Inc.
@c For copying conditions, see the file gpc.texi.
@c This file is part of the GPC Manual.
@c
@c Author: Frank Heckenbach <frank@pascal.gnu.de>
@c
@c Last modification: 2004-01-01 (file up to date)

You will need certain additional libraries when you compile some of
the units. These can be found in the directory
@uref{http://www.gnu-pascal.de/libs/}.

Currently, there are the following libraries:

@table @asis
@item gmp
Arithmetic for integers, rationals and real numbers with
arbitrary size and precision. Used by the GMP unit.

@item rx
Regular expression matching and substitution. Used by the RegEx
unit.

@item ncurses
@itemx PDCurses
Screen handling. Used by the CRT unit. Depending on your system,
you have the following choices:

Unix: You can compile terminal applications with ncurses and
applications that run in an X11 window with PDCurses (though
terminal applications can, of course, also run in an xterm under
X11). ncurses is used by default. If you want to use PDCurses
(a.k.a. XCurses), give the option @samp{-DX11} when compiling CRT.

Dos with DJGPP and MS-Windows with mingw: Only PDCurses is
available and will be used by default.

MS-Windows with Cygwin: PDCurses and ncurses are available.
PDCurses is used by default. If you want to use ncurses, give
the option @samp{-DUSE_NCURSES} when compiling CRT.

Other systems: Please see the @file{README}s and installation
instructions of PDCurses and ncurses to find out which one(s)
can be built on your system. See the conditionals at the end of
crt.inc and crtc.h (and change them if necessary) on which
library is used by default.

@item intl
Internationalization. Used by the Intl unit. On some systems, it is
part of the system library (libc).

@item ElectricFence
This library is not used by any GPC unit. It is a debugging tool to
assist you in finding memory allocation bugs. To use it, just link
it to your program, either on the command line (@samp{-lefence}) or
in the source code (@samp{@{$L efence@}}) which you might want to
put into an @samp{@{$ifdef DEBUG@}} or similar since using libefence
is only recommended for debugging.
@end table

The source code of the libraries is available in the main
@samp{libs} directory. Most libraries come with one or several
patches which should be applied before compiling them.

Binaries for some platforms are available in the
@file{binary/@var{platform}} subdirectories. If you compile the
libraries for other platforms, be invited to make the binaries
available to us for distribution on the web site.

There are also the following files:

@table @file
@item terminfo-linux.tar.gz
This is a patch to enable ncurses programs to make use of the
ability of Linux 2.2 and newer kernels to produce a block cursor
when needed. The present patch can be installed without recompiling
anything, just by copying some files into place. More details can be
found in the @file{README} file included in this archive. The patch
will not do any harm on older kernels. Please note that @strong{not}
only on Linux machines it is useful to install the patch. Installing
them on any other machine will allow users who telnet in from a
Linux console to profit from the block cursor capability. Besides,
some Unix systems have installed older Linux terminfo entries or
none at all, so it's a good thing, anyway, to give them a current
version. The patch is included in the terminfo database of ncurses
5.0, so if you install ncurses 5.0 (source or binary), you don't
need to get the patch separately. But you can install it on a system
with an older ncurses version if you don't feel like upgrading
ncurses altogether.

@item tsort-2.9i.zip
A little utility (extracted from util-linux-2.9i, but not Linux
specific), needed for the configuration of the rx library. You
need it only if you compile rx yourself (and if it's not
already present on your system), not when using a rx binary.
@end table
