% \iffalse meta-comment
%
% Copyright (C) 1989--1993 by Frank Mittelbach, Rainer Schoepf.
% All rights reserved.
% 
% This file is part of the NFSS2 (New Font Selection Scheme) package.
% 
%  This package is distributed in the hope that it will be useful,
%  but WITHOUT ANY WARRANTY; without even the implied warranty of
%  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
% 
% 
% IMPORTANT NOTICE:
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% etc.
% \fi
\def\fileversion{v2.0c}
\def\filedate{93/04/15}
\def\docdate {93/03/19}

% \CheckSum{27}
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%\iffalse   % This is a META comment
%
% File `fdprefix.dtx'.
% Copyright (C) 1993 Frank Mittelbach and Rainer Sch\"opf,
% all rights reserved.
%
%\fi
%
% \title{Setting the search path for font definition {\tt .fd}
% files\thanks{This file has version number \fileversion, dated
% \filedate.  The documentation was last updated on \docdate.}}
%
% \author{Frank Mittelbach \and Alan Jeffrey}
%
% \maketitle
%
% \MakeShortVerb{\|}
% \def\dst{{\csname mediumseries\endcsname\sc docstrip}}
% \setcounter{StandardModuleDepth}{1}
%
% \section{Overview}
%
% \TeX{} has two ways of opening files, through |\input| or through
% |\openin|.  One of the common uses of |\openin| is to find out
% whether a file exists before opening it.  For example, when you
% first ask for a font family |cmss| in encoding |T1|, \LaTeX{} will
% try to read a file called |T1cmss.fd|, and uses |\openin| to find
% out if the file exists.
%
% Unfortunately, on some \TeX{} installations, \TeX{} looks in
% different directories for |\input| and |\openin|.  This means that
% although we can use |\openin| to check for files in the current
% directory we can't use it to check for a file in the \TeX{}'s
% standard {\em inputs\/} directories, where files like |T1cmss.fd| are
% kept.
%
% Therefore, the file |fdprefix.tex| defines a macro |\fd@prefix|
% telling Ini\TeX{} where the |.fd| live on your system.  This file
% will be generated automatically by the |fdprefix.ins| installation
% file.\footnote{You should run {\tt fdprefix.ins} through \LaTeX{} in
% a directory other than one of the \TeX{} inputs directories, and
% then answer some questions about your \TeX{} installation.}
%
% If your system has the same |\openin| path as its |\input| path, the
% |\fd@prefix| macro will be empty which means that the |.fd| files
% live in some directory that is search by \TeX.\footnote{Even on such
% systems you can define {\tt\string\fd@prefix} by hand to force
% \TeX{} to fetch all {\tt.fd} files from some specific directory
% which may or may not belong to the standard system directories.}
%
% If your system has a different |\openin| path from its |\input|
% path, the |\fd@prefix| macro will contain the prefix to the
% directory in which you place {\em all\/} |.fd| files.
%
% Examples values of |\fd@prefix| are:
% \begin{center}
% \begin{tabular}{ll}
%    |c:/emtex/texinput/|  & under MS-DOS with {\tt emTeX} \\
%    |/usr/local/lib/tex/macros/| & under UNIX with {\tt web2c} \\
%    |Hard-Disk:TeX:TeX-inputs:| & on a Macintosh with Oz\TeX 
%  \end{tabular}
%  \end{center}
% Note that most \TeX{} implementations will not allow spaces in file
% names.  You should therefor ensure that your \TeX{} inputs path does
% not inlude any spaces.  Macintosh users may need to rename their
% hard disks, since a |\fd@prefix| value of 
% |Macintosh HD:TeX:TeX-inputs| will not work.
%
% You can change the definition in the file |fdprefix.tex| later on by
% hand if you decide to move the |.fd| files to some other place.
% However, keep in mind that you then have to redo the format
% generation since the definition of |\fd@prefix| saved in the
% format file is the one that is used by NFSS2.
%
% Please also note, that during format generation some |.fd| files are
% loaded. If the |\fd@prefix| macro is non-empty Ini\TeX{} will only
% look into that directory for finding them. You therefore have to
% move them to this directory prior to making the format.
%
% On systems that do have the same search path for both commands the
% |\fd@prefix| macro is empty and you don't have to worry about it.
%
% The generation of the |fdprefix.tex| file is completely done by the
% \dst{} program. This is a rather unusual use of it and the
% interested reader may enjoy looking at the coding in the file
% |fdprefix.ins|.
%
% \section{Special system requirements}
%
% On some operating systems a search path isn't specified by prefixing
% the file name with a suitable string. For example, on an MVS
% installation the |.fd| may be installed in a `partition dataset'
% which would then need the following syntax:
% \begin{quote}
%   |<sys3.texinput>fd(|\meta{base-file-name}|)|
% \end{quote}
% Note that a) there is a closing parenthesis after the file name and
% b) that the file extension moved in front of the
% \meta{base-file-name}, e.g.\ the file |T1cmr.fd| would become
% |<sys3.texinput>fd(T1cmr)|.
%
% Such a syntax can't be expressed during the main installation
% routine of NFSS since there you can only specify a prefix.
% However, you can modify the |fdprefix.tex| file by hand to achieve the
% desired result. 
%
% In such a case you have to define the |\fd@prefix| macro as a macro
% with two arguments delimited (!) by `|.fd|'. Your macro will then
% receive the encoding and the family name as arguments whenever NFSS
% internally tries to read a |.fd| file. Thus for the
% MVS operating system you could define your |\fd@prefix| to be
% \begin{quote}
%    |\def\fd@prefix#1#2.fd{<sys3.texinput>fd(#1#2)}|
% \end{quote}
% This is messy, no doubt, but then on most operating systems you won't 
% need such a complex redefinition.
%
% \StopEventually{}
%
% \section{A driver for this document}
%
% The next bit of code contains the documentation driver file for
% \TeX{}, i.e., the file that will produce the documentation you are
% currently reading. It will be extracted from this file by the 
% \dst{} program.
%    \begin{macrocode}
%<*driver>
\documentstyle[doc]{article}

% dimensions from ltugboat.sty:

\setlength\textwidth{31pc} 
\setlength\textheight{54pc}
\setlength{\parindent}{0pt}
\setlength{\parskip}{2pt plus 1pt minus 1pt}
\setlength{\oddsidemargin}{8pc} 
\setlength{\marginparwidth}{8pc}
\setlength{\topmargin}{-2.5pc} 
\setlength{\headsep}{20pt}
\setlength{\columnsep}{1.5pc} 
\setlength{\columnwidth}{18.75pc}

\DisableCrossrefs

\CodelineIndex     % Index code by line number

\OnlyDescription   % comment out for implementation details

\begin{document}
   \DocInput{fdprefix.dtx}
\end{document}
%</driver>
%    \end{macrocode}
%
% \Finale
% \DeleteShortVerb{\|}
%
\endinput