This file documents the Kpathsea library for path searching.

Copyright © 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008 Karl Berry & Olaf Weber.

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Free Software Foundation.

Kpathsea library
****************

This manual documents how to install and use the Kpathsea library for filename lookup.  It corresponds to version 3.5.6dev, released in March 2008.

Introduction
************

This manual corresponds to version 3.5.6dev of the Kpathsea library, released in March 2008.

The library's fundamental purpose is to return a filename from a list of directories specified by the user, similar to what shells do when looking up program names to execute.

The following software, all of which we maintain, uses this library:

  * Dviljk (see the dvilj man page)

  * Dvipsk (see Introduction (Dvips: A DVI driver))

  * GNU font utilities (see Introduction (GNU font utilities))

  * Web2c (see Introduction (Web2c: A TeX implementation))

  * Xdvik (see the xdvi man page)

Other software that we do not maintain also uses it.

We are still actively maintaining the library (and probably always will be, despite our hopes).  If you have comments or suggestions, please send them to us (see Reporting bugs).

We distribute the library under the GNU Library General Public License (LGPL).  In short, this means if you write a program using the library, you must (offer to) distribute the source to the library, along with any changes you have made, and allow anyone to modify the library source and distribute their modifications.  It does not mean you have to distribute the source to your program, although we hope you will.  See the files GPL and LGPL for the text of the GNU licenses.

If you know enough about TeX to be reading this manual, then you (or your institution) should consider joining the TeX Users Group (if you're already a member, great!).  TUG produces the periodical TUGboat, sponsors an annual meeting and publishes the proceedings, and arranges courses on TeX for all levels of users throughout the world.  Anyway, here is the address:

     TeX Users Group
     P.O. Box 2311
     Portland OR 97208-2311
     USA
     phone: +1 503 223-9994
     fax:   +1 503 223-3960
     email: tug@tug.org

History
=======

(This section is for those people who are curious about how the library came about.)  (If you like to read historical accounts of software, we urge you to seek out the GNU Autoconf manual and the ``Errors of TeX'' paper by Don Knuth, published in Software---Practice and Experience 19(7), July 1989.)

[Karl writes.]  My first ChangeLog entry for Web2c seems to be February 1990, but I may have done some work before then.  In any case, Tim Morgan and I were jointly maintaining it for a time.  (I should mention here that Tim had made Web2c into a real distribution long before I had ever used it or even heard of it, and Tom Rokicki did the original implementation.  I was using pxp and pc on VAX 11/750's and the hot new Sun 2 machines.)

It must have been later in 1990 and 1991 that I started working on TeX for the Impatient. Dvips, Xdvi, Web2c, and the GNU fontutils (which I was also writing at the time) all used different environment variables, and, more importantly, had different bugs in their path searching. This became extremely painful, as I was stressing everything to the limit working on the book.  I also desperately wanted to implement subdirectory searching, since I couldn't stand putting everything in one big directory, and also couldn't stand having to explicitly specify cm, pandora, ... in a path.

In the first incarnation, I just hacked separately on each program---that was the original subdirectory searching code in both Xdvi and Dvips, though I think Paul Vojta has completely rewritten Xdvi's support by now.  That is, I tried to go with the flow in each program, rather than changing the program's calling sequences to conform to common routines.

Then, as bugs inevitably appeared, I found I was fixing the same thing three times (Web2c and fontutils were always sharing code, since I maintained those---there was no Dvipsk or Xdvik or Dviljk at this point).  After a while, I finally started sharing source files.  They weren't yet a library, though.  I just kept things up to date with shell scripts.  (I was developing on a 386 running ISC 2.2 at the time, and so didn't have symbolic links.  An awful experience.)

The ChangeLogs for Xdvik and Dvipsk record initial releases of those distributions in May and June 1992.  I think it was because I was tired of the different configuration strategies of each program, not so much because of the path searching.  (Autoconf was being developed by David MacKenzie and others, and I was adapting it to TeX and friends.)

I started to make a separate library that other programs could link with on my birthday in April 1993, according to the ChangeLog.  I don't remember exactly why I finally took the time to make it a separate library; a conversation with david zuhn that initiated it.  Just seemed like it was time.

Dviljk got started in March 1994 after I bought a Laserjet 4.  (Kpathsea work got suspended while Norm Walsh and I, with Gustaf Neumann's help, implemented a way for TeX to get at all those neat builtin LJ4 fonts ... such a treat to have something to typeset in besides Palatino!)

By spring of 1995, I had implemented just about all the path-searching features in Kpathsea that I plan to, driven beyond my initial goals by Thomas Esser and others.  I then started to integrate Web2c with Kpathsea. After the release of a stable Web2c, I hope to be able to stop development, and turn most of my attention back to making fonts for GNU. (Always assuming Micros**t hasn't completely obliterated Unix by then, or that software patents haven't stopped software development by anybody smaller than a company with a million-dollar-a-year legal budget.  Which is actually what I think is likely to happen, but that's another story...)

[Olaf writes.]  At the end of 1997, UNIX is still alive and kicking, individuals still develop software, and Web2c development still continues.  Karl had been looking for some time for someone to take up part of the burden, and I volunteered.

     [file install.texi not included]
     [file hier.texi not included]
     [file unixtex.texi not included]
     [file bugs.texi not included]

Path searching
**************

This chapter describes the generic path searching mechanism Kpathsea provides.  For information about searching for particular file types (e.g., TeX fonts), see the next chapter.

Searching overview
==================

A search path is a colon-separated list of path elements, which are directory names with a few extra frills.  A search path can come from (a combination of) many sources; see below.  To look up a file foo along a path .:/dir, Kpathsea checks each element of the path in turn: first ./foo, then /dir/foo, returning the first match (or possibly all matches).

The ``colon'' and ``slash'' mentioned here aren't necessarily : and / on non-Unix systems.  Kpathsea tries to adapt to other operating systems' conventions.

To check a particular path element E, Kpathsea first sees if a prebuilt database (see Filename database) applies to E, i.e., if the database is in a directory that is a prefix of E.  If so, the path specification is matched against the contents of the database.

If the database does not exist, or does not apply to this path element, or contains no matches, the filesystem is searched (if this was not forbidden by the specification with !! and if the file being searched for must exist).  Kpathsea constructs the list of directories that correspond to this path element, and then checks in each for the file being searched for.  (To help speed future lookups of files in the same directory, the directory in which a file is found is floated to the top of the directory list.)

The ``file must exist'' condition comes into play with VF files and input files read by the TeX \openin command.  These files may not exist (consider cmr10.vf), and so it would be wrong to search the disk for them.  Therefore, if you fail to update ls-R when you install a new VF file, it will never be found.

Each path element is checked in turn: first the database, then the disk. If a match is found, the search stops and the result is returned.  This avoids possibly-expensive processing of path specifications that are never needed on a particular run.  (Unless the search explicitly requested all matches.)

Although the simplest and most common path element is a directory name, Kpathsea supports additional features in search paths: layered default values, environment variable names, config file values, users' home directories, and recursive subdirectory searching.  Thus, we say that Kpathsea expands a path element, meaning transforming all the magic specifications into the basic directory name or names.  This process is described in the sections below.  It happens in the same order as the sections.

Exception to all of the above: If the filename being searched for is absolute or explicitly relative, i.e., starts with / or ./ or ../, Kpathsea simply checks if that file exists.

Ordinarily, if Kpathsea tries to access a file or directory that cannot be read, it gives a warning.  This is so you will be alerted to directories or files that accidentally lack read permission (for example, a lost+found).  If you prefer not to see these warnings, include the value readable in the TEX_HUSH environment variable or config file value.

This generic path searching algorithm is implemented in kpathsea/pathsearch.c.  It is employed by a higher-level algorithm when searching for a file of a particular type (see File lookup, and Glyph lookup).

Path sources
============

A search path can come from many sources.  In the order in which Kpathsea uses them:

 1. A user-set environment variable, e.g., TEXINPUTS. Environment variables with an underscore and the program name appended override; for example, TEXINPUTS_latex overrides TEXINPUTS if the program being run is named latex.

 2. A program-specific configuration file, e.g., an S /a:/b line in Dvips' config.ps (see Config files (Dvips)).

 3. A line in a Kpathsea configuration file texmf.cnf, e.g., TEXINPUTS=/c:/d (see below).

 4. The compile-time default (specified in kpathsea/paths.h).

You can see each of these values for a given search path by using the debugging options (see Debugging).

These sources may be combined via default expansion (see Default expansion).

Config files
------------

As mentioned above, Kpathsea reads runtime configuration files named texmf.cnf for search path and other definitions.  The search path used to look for these configuration files is named TEXMFCNF, and is constructed in the usual way, as described above, except that configuration files cannot be used to define the path, naturally; also, an ls-R database is not used to search for them.

Kpathsea reads all texmf.cnf files in the search path, not just the first one found; definitions in earlier files override those in later files.  Thus, if the search path is .:$TEXMF, values from ./texmf.cnf override those from $TEXMF/texmf.cnf.

If Kpathsea cannot find any texmf.cnf file, it reports a warning including all the directories it checked.  If you don't want to see this warning, set the environment variable KPATHSEA_WARNING to the single character 0 (zero, not oh).

While (or instead of) reading this description, you may find it helpful to look at the distributed texmf.cnf, which uses or at least mentions most features.  The format of texmf.cnf files follows:

  * Comments start with % and continue to the end of the line.

  * Blank lines are ignored.

  * A \ at the end of a line acts as a continuation character, i.e., the next line is appended.  Whitespace at the beginning of continuation lines is not ignored.

  * Each remaining line must look like

          VARIABLE [. PROGNAME] [=] VALUE

     where the = and surrounding whitespace is optional.

  * The VARIABLE name may contain any character other than whitespace, =, or ., but sticking to A-Za-z_ is safest.

  * If .PROGNAME is present, the definition only applies if the program that is running is named (i.e., the last component of argv[0] is) PROGNAME or PROGNAME.exe.  This allows different flavors of TeX to have different search paths, for example.

  * VALUE may contain any characters except % and @. (These restrictions are only necessary because of the processing done on texmf.cnf at build time, so you can stick those characters in after installation if you have to.)  The $VAR.PROG feature is not available on the right-hand side; instead, you must use an additional variable (see below for example).  A ; in VALUE is translated to : if running under Unix; this is useful to write a single texmf.cnf which can be used under both Unix and NT.

  * All definitions are read before anything is expanded, so you can use variables before they are defined (like Make, unlike most other programs).

Here is a configuration file fragment illustrating most of these points:

     % TeX input files -- i.e., anything to be found by \input or \openin ...
     latex209_inputs = .:$TEXMF/tex/latex209//:$TEXMF/tex//
     latex2e_inputs = .:$TEXMF/tex/latex//:$TEXMF/tex//
     TEXINPUTS = .:$TEXMF/tex//
     TEXINPUTS.latex209 = $latex209_inputs
     TEXINPUTS.latex2e = $latex2e_inputs
     TEXINPUTS.latex = $latex2e_inputs

Although this format has obvious similarities to Bourne shell scripts---change the comment character to #, disallow spaces around the =, and get rid of the .NAME convention, and it could be run through the shell.  But there seemed little advantage to doing this, since all the information would have to passed back to Kpathsea and parsed there anyway, since the sh process couldn't affect its parent's environment.

The implementation of all this is in kpathsea/cnf.c.

Path expansion
==============

Kpathsea recognizes certain special characters and constructions in search paths, similar to that in shells.  As a general example: ~$USER/{foo,bar}//baz expands to all subdirectories under directories foo and bar in $USER's home directory that contain a directory or file baz.  These expansions are explained in the sections below.

Default expansion
-----------------

If the highest-priority search path (see Path sources) contains an extra colon (i.e., leading, trailing, or doubled), Kpathsea inserts at that point the next-highest-priority search path that is defined.  If that inserted path has an extra colon, the same happens with the next-highest.  (An extra colon in the compile-time default value has unpredictable results, so installers beware.)

For example, given an environment variable setting

     setenv TEXINPUTS /home/karl:

and a TEXINPUTS value from texmf.cnf of

     .:$TEXMF//tex

then the final value used for searching will be:

     /home/karl:.:$TEXMF//tex

Put another way, default expansion works on ``formats'' (search paths), and not directly on environment variables.  Example, showing the trailing : ignored in the first case and expanded in the second:

     $ env TTFONTS=/tmp: kpsewhich --expand-path '$TTFONTS'
     /tmp
     $ env TTFONTS=/tmp: kpsewhich --show-path=.ttf
     /tmp:.:/home/olaf/texmf/fonts/truetype//:...

Since Kpathsea looks for multiple configuration files, it would be natural to expect that (for example) an extra colon in ./texmf.cnf would expand to the path in $TEXMF/texmf.cnf. Or, with Dvips' configuration files, that an extra colon in config.$PRINTER would expand to the path in config.ps. This doesn't happen.  It's not clear this would be desirable in all cases, and trying to devise a way to specify the path to which the extra colon should expand seemed truly baroque.

Technicality: Since it would be useless to insert the default value in more than one place, Kpathsea changes only one extra : and leaves any others in place (they will eventually be ignored).  Kpathsea checks first for a leading :, then a trailing :, then a doubled :.

You can trace this by debugging ``paths'' (see Debugging). Default expansion is implemented in the source file kpathsea/kdefault.c.

Variable expansion
------------------

$foo or ${foo} in a path element is replaced by (1) the value of an environment variable foo (if defined); (2) the value of foo from texmf.cnf (if defined); (3) the empty string.

If the character after the $ is alphanumeric or _, the variable name consists of all consecutive such characters. If the character after the $ is a {, the variable name consists of everything up to the next } (braces may not be nested around variable names).  Otherwise, Kpathsea gives a warning and ignores the $ and its following character.

You must quote the $'s and braces as necessary for your shell. Shell variable values cannot be seen by Kpathsea, i.e., ones defined by set in C shells and without export in Bourne shells.

For example, given

     setenv tex /home/texmf
     setenv TEXINPUTS .:$tex:${tex}prev

the final TEXINPUTS path is the three directories:

     .:/home/texmf:/home/texmfprev

The .PROGNAME suffix on variables and _PROGNAME on environment variable names are not implemented for general variable expansions.  These are only recognized when search paths are initialized (see Path sources).

Variable expansion is implemented in the source file kpathsea/variable.c.

Tilde expansion
---------------

A leading ~ in a path element is replaced by the value of the environment variable HOME, or . if HOME is not set.  On Windows, the environment variable USERPROFILE is checked instead of HOME.

A leading ~USER in a path element is replaced by USER's home directory from the system passwd database.

For example,

     setenv TEXINPUTS ~/mymacros:

will prepend a directory mymacros in your home directory to the default path.

As a special case, if a home directory ends in /, the trailing slash is dropped, to avoid inadvertently creating a // construct in the path.  For example, if the home directory of the user root is /, the path element ~root/mymacros expands to just /mymacros, not //mymacros.

Tilde expansion is implemented in the source file kpathsea/tilde.c.

Brace expansion
---------------

x{A,B}y expands to xAy:xBy. For example:

     foo/{1,2}/baz

expands to foo/1/baz:foo/2/baz.  : is the path separator on the current system; e.g., on a DOS system, it's ;.

Braces can be nested; for example, x{A,B{1,2}}y expands to xAy:xB1y:xB2y.

Multiple non-nested braces are expanded from right to left; for example, x{A,B}{1,2}y expands to x{A,B}1y:x{A,B}2y, which expands to xA1y:xB1y:xA2y:xB2y.

This feature can be used to implement multiple TeX hierarchies, by assigning a brace list to $TEXMF, as mentioned in texmf.in.

You can also use the path separator in stead of the comma.  The last example could have been written x{A:B}{1:2}y.

Brace expansion is implemented in the source file kpathsea/expand.c.  It is a modification of the Bash sources, and is thus covered by the GNU General Public License, rather than the Library General Public License that covers the rest of Kpathsea.

KPSE_DOT expansion
------------------

When KPSE_DOT is defined in the environment, it names a directory that should be considered the current directory for the purpose of looking up files in the search paths.  This feature is needed by the mktex... scripts mktex scripts, because these change the working directory.  You should not ever define it yourself.

Subdirectory expansion
----------------------

Two or more consecutive slashes in a path element following a directory D is replaced by all subdirectories of D: first those subdirectories directly under D, then the subsubdirectories under those, and so on.  At each level, the order in which the directories are searched is unspecified.  (It's ``directory order'', and definitely not alphabetical.)

If you specify any filename components after the //, only subdirectories which match those components are included.  For example, /a//b would expand into directories /a/1/b, /a/2/b, /a/1/1/b, and so on, but not /a/b/c or /a/1.

You can include multiple // constructs in the path.

// at the beginning of a path is ignored; you didn't really want to search every directory on the system, did you?

I should mention one related implementation trick, which I took from GNU find.  Matthew Farwell suggested it, and David MacKenzie implemented it.

The trick is that in every real Unix implementation (as opposed to the POSIX specification), a directory which contains no subdirectories will have exactly two links (namely, one for . and one for ..). That is to say, the st_nlink field in the stat structure will be two.  Thus, we don't have to stat everything in the bottom-level (leaf) directories---we can just check st_nlink, notice it's two, and do no more work.

But if you have a directory that contains a single subdirectory and 500 regular files, st_nlink will be 3, and Kpathsea has to stat every one of those 501 entries.  Therein lies slowness.

You can disable the trick by undefining UNIX_ST_LINK in kpathsea/config.h. (It is undefined by default except under Unix.)

Unfortunately, in some cases files in leaf directories are stat'd: if the path specification is, say, $TEXMF/fonts//pk//, then files in a subdirectory .../pk, even if it is a leaf, are checked. The reason cannot be explained without reference to the implementation, so read kpathsea/elt-dirs.c (search for may descend) if you are curious.  And if you can find a way to solve the problem, please let me know.

Subdirectory expansion is implemented in the source file kpathsea/elt-dirs.c.

Filename database (ls-R)
========================

Kpathsea goes to some lengths to minimize disk accesses for searches (see Subdirectory expansion).  Nevertheless, at installations with enough directories, searching each possible directory for a given file can take an excessively long time (depending on the speed of the disk, whether it's NFS-mounted, how patient you are, etc.).

In practice, a font tree containing the standard PostScript and PCL fonts is large enough for searching to be noticeably slow on typical systems these days.  Therefore, Kpathsea can use an externally-built ``database'' file named ls-R that maps files to directories, thus avoiding the need to exhaustively search the disk.

A second database file aliases allows you to give additional names to the files listed in ls-R.  This can be helpful to adapt to ``8.3'' filename conventions in source files.

The ls-R and aliases features are implemented in the source file kpathsea/db.c.

ls-R
----

As mentioned above, you must name the main filename database ls-R.  You can put one at the root of each TeX installation hierarchy you wish to search ($TEXMF by default); most sites have only one hierarchy.  Kpathsea looks for ls-R files along the TEXMFDBS path, so that should presumably match the list of hierarchies.

The recommended way to create and maintain ls-R is to run the mktexlsr script, which is installed in $(bindir) (/usr/local/bin by default).  That script goes to some trouble to follow symbolic links as necessary, etc.  It's also invoked by the distributed mktex... scripts.

At its simplest, though, you can build ls-R with the command

     cd /YOUR/TEXMF/ROOT && ls -LAR ./ >ls-R

presuming your ls produces the right output format (see the section below).  GNU ls, for example, outputs in this format. Also presuming your ls hasn't been aliased in a system file (e.g., /etc/profile) to something problematic, e.g., ls --color=tty.  In that case, you will have to disable the alias before generating ls-R.  For the precise definition of the file format, see Database format.

Regardless of whether you use the supplied script or your own, you will almost certainly want to invoke it via cron, so when you make changes in the installed files (say if you install a new LaTeX package), ls-R will be automatically updated.

The -A option to ls includes files beginning with . (except for . and ..), such as the file .tex included with the LaTeX tools package.  (On the other hand, directories whose names begin with . are always ignored.)

If your system does not support symbolic links, omit the -L.

ls -LAR /YOUR/TEXMF/ROOT will also work.  But using ./ avoids embedding absolute pathnames, so the hierarchy can be easily transported.  It also avoids possible trouble with automounters or other network filesystem conventions.

Kpathsea warns you if it finds an ls-R file, but the file does not contain any usable entries.  The usual culprit is running plain ls -R instead of ls -LR ./ or ls -R /YOUR/TEXMF/ROOT.  Another possibility is some system directory name starting with a . (perhaps if you are using AFS); Kpathsea ignores everything under such directories.

Because the database may be out-of-date for a particular run, if a file is not found in the database, by default Kpathsea goes ahead and searches the disk. If a particular path element begins with !!, however, only the database will be searched for that element, never the disk.  If the database does not exist, nothing will be searched.  Because this can surprise users (``I see the font foo.tfm when I do an ls; why can't Dvips find it?''), it is not in any of the default search paths.

Filename aliases
----------------

In some circumstances, you may wish to find a file under several names. For example, suppose a TeX document was created using a DOS system and tries to read longtabl.sty.  But now it's being run on a Unix system, and the file has its original name, longtable.sty.  The file won't be found.  You need to give the actual file longtable.sty an alias longtabl.sty.

You can handle this by creating a file aliases as a companion to the ls-R for the hierarchy containing the file in question.  (You must have an ls-R for the alias feature to work.)

The format of aliases is simple: two whitespace-separated words per line; the first is the real name longtable.sty, and second is the alias (longtabl.sty).  These must be base filenames, with no directory components.  longtable.sty must be in the sibling ls-R.

Also, blank lines and lines starting with % or # are ignored in aliases, to allow for comments.

If a real file longtabl.sty exists, it is used regardless of any aliases.

Database format
---------------

The ``database'' read by Kpathsea is a line-oriented file of plain text. The format is that generated by GNU (and most other) ls programs given the -R option, as follows.

  * Blank lines are ignored.

  * If a line begins with / or ./ or ../ and ends with a colon, it's the name of a directory.  (../ lines aren't useful, however, and should not be generated.)

  * All other lines define entries in the most recently seen directory. /'s in such lines will produce possibly-strange results.

  * Files with no preceding directory line are ignored.

For example, here's the first few lines of ls-R (which totals about 30K bytes) on my system:

     bibtex
     dvips
     fonts
     ls-R
     metafont
     metapost
     tex
     web2c

     ./bibtex:
     bib
     bst
     doc

     ./bibtex/bib:
     asi.bib
     btxdoc.bib
     ...

kpsewhich: Standalone path searching
====================================

The Kpsewhich program exercises the path searching functionality independent of any particular application.  This can also be useful as a sort of find program to locate files in your TeX hierarchies, perhaps in administrative scripts.  It is used heavily in the distributed mktex... scripts.

Synopsis:

     kpsewhich OPTION... FILENAME...

The options and filename(s) to look up can be intermixed. Options can start with either - or --, and any unambiguous abbreviation is accepted.

Path searching options
----------------------

Kpsewhich looks up each non-option argument on the command line as a filename, and returns the first file found.

Various options alter the path searching behavior:

--all
     Report all matches found, one per line.  By default, if there is more than one match, just one will be reported (chosen effectively at random).

--dpi=NUM
     Set the resolution to NUM; this only affects gf and pk lookups.  -D is a synonym, for compatibility with Dvips.  Default is 600.

--engine=NAME
     Set the engine name to NAME.  By default it is not set.  The engine name is used in some search paths to allow files with the same name but used by different engines to coexist.

--format=NAME
     Set the format for lookup to NAME.  By default, the format is guessed from the filename, with tex being used if nothing else fits.  The recognized filename extensions (including any leading .) are also allowable NAMEs.

     All formats also have a name, which is the only way to specify formats with no associated suffix.  For example, for Dvips configuration files you can use --format="dvips config".  (The quotes are for the sake of the shell.)

     When the filename being searched for is config.ps, the format is automatically switched to dvips config.  Similarly, when the filename is pdftex.cfg, the format is switched to pdftex config (although pdftex.cfg is not used any more; look for pdftexconfig.tex instead.)

     Here's the current list of recognized names and the associated suffixes. See Supported file formats, for more information on each of these.

          gf: gf
          pk: pk
          bitmap font
          afm: .afm
          base: .base
          bib: .bib
          bst: .bst
          cnf: .cnf
          ls-R: ls-R
          fmt: .fmt
          map: .map
          mem: .mem
          mf: .mf
          mfpool: .pool
          mft: .mft
          mp: .mp
          mppool: .pool
          MetaPost support
          ocp: .ocp
          ofm: .ofm .tfm
          opl: .opl
          otp: .otp
          ovf: .ovf
          ovp: .ovp
          graphic/figure: .eps .epsi
          tex: .tex
          TeX system documentation
          texpool: .pool
          TeX system sources
          PostScript header/font: .pro
          Troff fonts
          tfm: .tfm
          type1 fonts: .pfa .pfb
          vf: .vf
          dvips config
          ist: .ist
          truetype fonts: .ttf .ttc
          type42 fonts
          web2c files
          other text files
          other binary files
          misc fonts
          web: .web
          cweb: .w .web
          enc: .enc
          cmap: .cmap
          sfd: .sfd
          opentype fonts
          pdftex config
          lig files: .lig
          texmfscripts

     This option and --path are mutually exclusive.

--interactive
     After processing the command line, read additional filenames to look up from standard input.

-mktex=FILETYPE
-no-mktex=FILETYPE
     Turn on or off the mktex script associated with FILETYPE. The only values that make sense for FILETYPE are pk, mf, tex, and tfm. By default, all are off in Kpsewhich.  See mktex scripts.

--mode=STRING
     Set the mode name to STRING; this also only affects gf and pk lookups.  No default: any mode will be found.  See mktex script arguments.

--must-exist
     Do everything possible to find the files, notably including searching the disk.  By default, only the ls-R database is checked, in the interest of efficiency.

--path=STRING
     Search along the path STRING (colon-separated as usual), instead of guessing the search path from the filename.  // and all the usual expansions are supported (see Path expansion).  This option and --format are mutually exclusive.  To output the complete directory expansion of a path, instead of doing a one-shot lookup, see --expand-path and --show-path in the following section.

--progname=NAME
     Set the program name to NAME; default is kpsewhich.  This can affect the search paths via the .PROGNAM feature in configuration files (see Config files).

--subdir=STRING
     Report only those matches whose directory part ends with STRING (compared literally, except case is ignored on a case-insensitive operating system).  For example, suppose there are two matches for a given name:

          kpsewhich foo.sty
          => /some/where/foo.sty
          /another/place/foo.sty

     Then we can narrow the result to what we are interested in with --subdir:

          kpsewhich --subdir=where foo.sty
          => /some/where/foo.sty

          kpsewhich --subdir=place foo.sty
          => /another/place/foo.sty

     The string to match must be at the end of the directory part of the match, and it is taken literally, with no pattern matching:

          kpsewhich --subdir=another foo.sty
          =>

     The string to match may cross directory components:

          kpsewhich --subdir=some/where foo.sty
          => /some/where/foo.sty

     --subdir implies --all; if there is more than one match, they will all be reported (in our example, both where and place end in e):

          kpsewhich --subdir=e
          => /some/where/foo.sty
          /another/place/foo.sty

     Because of the above rules, the presence of a leading / is important, since it ``anchors'' the match to a full component name:

          kpsewhich --subdir=/lace foo.sty
          =>

     However, a trailing / is immaterial (and ignored), since the match always takes place at the end of the directory part:

          kpsewhich --subdir=lace/ foo.sty
          => /another/place/foo.sty

     The purpose of these rules is to make it convenient to find results only within a particular area of the tree.  For instance, a given script named foo.lua might exist within both texmf-dist/scripts/pkg1/ and texmf-dist/scripts/pkg2/. By specifying, say, --subdir=/pkg1, you can be sure of getting the one you are interested in.

     We only match at the end because a site might happen to install TeX in /some/coincidental/pkg1/path/, and we wouldn't want texmf-dist/scripts/pkg2/ to match that when searching for /pkg1.

Auxiliary tasks
---------------

Kpsewhich provides some additional features not strictly related to path lookup:

  * --debug=NUM sets the debugging options to NUM. See Debugging.

  * --var-value=VARIABLE outputs the value of VARIABLE, expanding $ (see Variable expansion and ~ (see Tilde expansion) constructs, but not performing other expansions.

  * --expand-braces=STRING outputs the variable and brace expansion of STRING.  See Path expansion.

  * --expand-var=STRING outputs the variable and tilde expansion of STRING.  For example, the mktex... scripts run kpsewhich --expand-var='$TEXMF' to find the root of the TeX system hierarchy.  See Path expansion.

  * --expand-path=STRING outputs the complete expansion of STRING, with each element separated by the usual path separator on the current system (; on Windows, : otherwise). This may be useful to construct a custom search path for a format not otherwise supported.  To retrieve the search path for a format that is already supported, see --show-path, next.

     Nonexistent directories are culled from the output:

          $ kpsewhich --expand-path '/tmp'
          => /tmp
          $ kpsewhich --expand-path '/nonesuch'
          =>

     For one-shot uses of an arbitrary (not built in to Kpathsea) path, see --path in the previous section.

  * --show-path=NAME shows the path that would be used for file lookups of file type NAME.  Either a filename extension (pk, .vf, etc.) or an integer can be used, just as with --format, described in the previous section.

Standard options
----------------

Kpsewhich accepts the standard GNU options:

  * --help prints a help message on standard output and exits.

  * --version prints the Kpathsea version number and exits.

TeX support
***********

Although the basic features in Kpathsea can be used for any type of path searching, it came about (like all libraries) with a specific application in mind: I wrote Kpathsea specifically for TeX system programs.  I had been struggling with the programs I was using (Dvips, Xdvi, and TeX itself) having slightly different notions of how to specify paths; and debugging was painful, since no code was shared.

Therefore, Kpathsea provides some TeX-specific formats and features. Indeed, many of the supposedly generic path searching features were provided because they seemed useful in that conTeXt (font lookup, particularly).

Kpathsea provides a standard way to search for files of any of the supported file types; glyph fonts are a bit different than all the rest. Searches are based solely on filenames, not file contents---if a GF file is named cmr10.600pk, it will be found as a PK file.

Supported file formats
======================

Kpathsea has support for a number of file types.  Each file type has a list of environment and config file variables that are checked to define the search path, and most have a default suffix that plays a role in finding files (see the next section).  Some also define additional suffixes, and/or a program to be run to create missing files on the fly.

Since environment variables containing periods, such as TEXINPUTS.latex, are not allowed on some systems, Kpathsea looks for environment variables with an underscore, e.g., TEXINPUTS_latex (see Config files).

The following table lists the above information.

afm
     (Adobe font metrics, see Metric files (Dvips)) AFMFONTS; suffix .afm.

base
     (Metafont memory dump, see Memory dumps (Web2c)) MFBASES, TEXMFINI; suffix .base.

bib
     (BibTeX bibliography source, see bibtex invocation (Web2c)) BIBINPUTS, TEXBIB; suffix .bib.

bst
     (BibTeX style file, see Basic BibTeX style files (Web2c)) BSTINPUTS; suffix .bst.

cmap
     (character map files) CMAPFONTS; suffix .cmap.

cnf
     (Runtime configuration files, see Config files) TEXMFCNF; suffix .cnf.

cweb
     (CWEB input files) CWEBINPUTS; suffixes .w, .web; additional suffix .ch.

dvips config
     (Dvips config.* files, such as config.ps, see Config files (Dvips)) TEXCONFIG.

enc files
     (encoding vectors) ENCFONTS; suffix .enc.

fmt
     (TeX memory dump, see Memory dumps (Web2c)) TEXFORMATS, TEXMFINI; suffix .fmt.

gf
     (generic font bitmap, see Glyph files (Dvips)) PROGRAMFONTS, GFFONTS, GLYPHFONTS, TEXFONTS; suffix gf.

graphic/figure
     (Encapsulated PostScript figures, see PostScript figures (Dvips)) TEXPICTS, TEXINPUTS; additional suffixes: .eps, .epsi.

ist
     (makeindex style files) TEXINDEXSTYLE, INDEXSTYLE; suffix .ist.

lig files
     (ligature definition files) LIGFONTS; suffix .lig.

ls-R
     (Filename databases, see Filename database) TEXMFDBS.

map
     (Fontmaps, see Fontmap) TEXFONTMAPS; suffix .map.

mem
     (MetaPost memory dump, see Memory dumps (Web2c)) MPMEMS, TEXMFINI; suffix .mem.

MetaPost support
     (MetaPost support files, used by DMP; see dmp invocation (Web2c)) MPSUPPORT.

mf
     (Metafont source, see mf invocation (Web2c)) MFINPUTS; suffix .mf; dynamic creation program: mktexmf.

mfpool
     (Metafont program strings, see pooltype invocation (Web2c)) MFPOOL, TEXMFINI; suffix .pool.

mft
     (MFT style file, see mft invocation (Web2c)) MFTINPUTS; suffix .mft.

misc fonts
     (font-related files that don't fit the other categories) MISCFONTS

mp
     (MetaPost source, see mpost invocation (Web2c)) MPINPUTS; suffix .mp.

mppool
     (MetaPost program strings, see pooltype invocation (Web2c)) MPPOOL, TEXMFINI; suffix .pool.

ocp
     (Omega compiled process files) OCPINPUTS;

     suffix .ocp; dynamic creation program: MakeOmegaOCP.

ofm
     (Omega font metrics) OFMFONTS, TEXFONTS;

     suffixes .ofm, .tfm; dynamic creation program: MakeOmegaOFM.

opentype fonts
     (OpenType fonts) OPENTYPEFONTS.

opl
     (Omega property lists) OPLFONTS, TEXFONTS; suffix .opl.

otp
     (Omega translation process files) OTPINPUTS; suffix .otp.

ovf
     (Omega virtual fonts) OVFFONTS, TEXFONTS; suffix .ovf.

ovp
     (Omega virtual property lists) OVPFONTS, TEXFONTS; suffix .ovp.

pdftex config
     (PDFTeX-specific configuration files) PDFTEXCONFIG.

pk
     (packed bitmap fonts, see Glyph files (Dvips)) PROGRAMFONTS (PROGRAM being XDVI, etc.), PKFONTS, TEXPKS, GLYPHFONTS, TEXFONTS; suffix pk; dynamic creation program: mktexpk.

PostScript header
     (downloadable PostScript, see Header files (Dvips)) TEXPSHEADERS, PSHEADERS; additional suffix .pro.

subfont definition files
     (subfont definition files) SFDFONTS suffix .sfd.

tex
     (TeX source, see tex invocation (Web2c)) TEXINPUTS; suffix .tex; additional suffixes: none, because such a list cannot be complete; dynamic creation program: mktextex.

TeX system documentation
     (Documentation files for the TeX system) TEXDOCS.

TeX system sources
     (Source files for the TeX system) TEXSOURCES.

texmfscripts
     (Architecture-independent executables distributed in the texmf tree) TEXMFSCRIPTS.

texpool
     (TeX program strings, see pooltype invocation (Web2c)) TEXPOOL, TEXMFINI; suffix .pool.

tfm
     (TeX font metrics, see Metric files (Dvips)) TFMFONTS, TEXFONTS; suffix .tfm; dynamic creation program: mktextfm.

Troff fonts
     (Troff fonts, used by DMP; see DMP invocation (Web2c)) TRFONTS.

truetype fonts
     (TrueType outline fonts) TTFONTS; suffixes .ttf, .ttc.

type1 fonts
     (Type 1 PostScript outline fonts, see Glyph files (Dvips)) T1FONTS, T1INPUTS, TEXPSHEADERS, DVIPSHEADERS; suffixes .pfa, .pfb.

type42 fonts
     (Type 42 PostScript outline fonts) T42FONTS.

vf
     (virtual fonts, see Virtual fonts (Dvips)) VFFONTS, TEXFONTS; suffix .vf.

web
     (WEB input files) WEBINPUTS; suffix .web; additional suffix .ch.

web2c files
     (files specific to the web2c implementation) WEB2C.

There are two special cases, because the paths and environment variables always depend on the name of the program: the variable name is constructed by converting the program name to upper case, and then appending INPUTS.  Assuming the program is called foo, this gives us the following table.

other text files
     (text files used by foo) FOOINPUTS.

other binary files
     (binary files used by foo) FOOINPUTS.

If an environment variable by these names are set, the corresponding texmf.cnf definition won't be looked at (unless, as usual, the environment variable value has an extra :).  See Default expansion.

For the font variables, the intent is that:

  * TEXFONTS is the default for everything.

  * GLYPHFONTS is the default for bitmap (or, more precisely, non-metric) files.

  * Each font format has a variable of its own.

  * Each program has its own font override path as well; e.g., DVIPSFONTS for Dvipsk.  Again, this is for bitmaps, not metrics.

File lookup
===========

This section describes how Kpathsea searches for most files (bitmap font searches are the exception, as described in the next section).

Here is the search strategy for a file NAME:

 1. If the file format defines default suffixes, and the suffix of NAME name is not already a known suffix for that format, try the name with each default appended, and use alternative names found in the fontmaps if necessary.  We postpone searching the disk as long as possible.  Example: given foo.sty, look for foo.sty.tex before foo.sty.  This is unfortunate, but allows us to find foo.bar.tex before foo.bar if both exist and we were given foo.bar.

 2. Search for NAME, and if necessary for alternative names found in the fontmaps.  Again we avoid searching the disk if possible.  Example: given foo, we look for foo.

 3. If the file format defines a program to invoke to create missing files, run it (see mktex scripts).

This is implemented in the routine kpse_find_file in kpathsea/tex-file.c.  You can watch it in action with the debugging options (see Debugging).

Glyph lookup
============

This section describes how Kpathsea searches for a bitmap font in GF or PK format (or either) given a font name (e.g., cmr10) and a resolution (e.g., 600).

Here is an outline of the search strategy (details in the sections below) for a file NAME at resolution DPI.  The search stops at the first successful lookup.

 1. Look for an existing file NAME.DPIFORMAT in the specified format(s).

 2. If NAME is an alias for a file F in the fontmap file texfonts.map, look for F.DPI.

 3. Run an external program (typically named mktexpk) to generate the font (see mktex scripts)

 4. Look for FALLBACK.DPI, where FALLBACK is some last-resort font (typically cmr10).

This is implemented in kpse_find_glyph_format in kpathsea/tex-glyph.c.

Basic glyph lookup
------------------

When Kpathsea looks for a bitmap font NAME at resolution DPI in a format FORMAT, it first checks each directory in the search path for a file NAME.DPIFORMAT; for example, cmr10.600pk.  Kpathsea looks for a PK file first, then a GF file.

If that fails, Kpathsea looks for dpiDPI/NAME.FORMAT; for example, dpi600/cmr10.pk. This is how fonts are typically stored on filesystems (such as DOS) that permit only three-character extensions.

If that fails, Kpathsea looks for a font with a close-enough DPI. ``Close enough'' is defined by the macro KPSE_BITMAP_TOLERANCE in kpathsea/tex-glyph.h to be DPI / 500 + 1.  This is slightly more than the 0.2% minimum allowed by the DVI standard (CTAN:/dviware/driv-standard/level-0).

Fontmap
-------

If a bitmap font or metric file is not found with the original name (see the previous section), Kpathsea looks through any fontmap files for an alias for the original font name.  These files are named texfonts.map and searched for along the TEXFONTMAPS environment/config file variable.  All texfonts.map files that are found are read; earlier definitions override later ones.

This feature is intended to help in two respects:

 1. An alias name is limited in length only by available memory, not by your filesystem.  Therefore, if you want to ask for Times-Roman instead of ptmr, you can (you get ptmr8r).

 2. A few fonts have historically had multiple names: specifically, LaTeX's ``circle font'' has variously been known as circle10, lcircle10, and lcirc10.  Aliases can make all the names equivalent, so that it no longer matters what the name of the installed file is; TeX documents will find their favorite name.

The format of fontmap files is straightforward:

  * Comments start with % and continue to the end of the line.

  * Blank lines are ignored.

  * Each nonblank line is broken up into a series of words: a sequence of non-whitespace characters.

  * If the first word is include, the second word is used as a filename, and it is searched for and read.

  * Otherwise, the first word on each line is the true filename;

  * the second word is the alias;

  * subsequent words are ignored.

If an alias has an extension, it matches only those files with that extension; otherwise, it matches anything with the same root, regardless of extension.  For example, an alias foo.tfm matches only when foo.tfm is being searched for; but an alias foo matches foo.vf, foo.600pk, etc.

As an example, here is an excerpt from the texfonts.map in the Web2c distribution.  It makes the circle fonts equivalent and includes automatically generated maps for most PostScript fonts available from various font suppliers.

     circle10        lcircle10
     circle10        lcirc10
     lcircle10       circle10
     lcircle10       lcirc10
     lcirc10         circle10
     lcirc10         lcircle10
     ...
     include adobe.map
     include apple.map
     include bitstrea.map
     ...

Fontmaps are implemented in the file kpathsea/fontmap.c. The Fontname distribution has much more information on font naming (see Introduction (Filenames for TeX fonts)).

Fallback font
-------------

If a bitmap font cannot be found or created at the requested size, Kpathsea looks for the font at a set of fallback resolutions.  You specify these resolutions as a colon-separated list (like search paths). Kpathsea looks first for a program-specific environment variable (e.g., DVIPSSIZES for Dvipsk), then the environment variable TEXSIZES, then a default specified at compilation time (the Make variable default_texsizes).  You can set this list to be empty if you prefer to find fonts at their stated size or not at all.

Finally, if the font cannot be found even at the fallback resolutions, Kpathsea looks for a fallback font, typically cmr10.  Programs must enable this feature by assigning to the global variable kpse_fallback_font or calling kpse_init_prog (see Calling sequence); the default is no fallback font.

Suppressing warnings
====================

Kpathsea provides a way to suppress selected usually-harmless warnings; this is useful at large sites where most users are not administrators, and thus the warnings are merely a source of confusion, not a help.  To do this, you set the environment variable or configuration file value TEX_HUSH to a colon-separated list of values.  Here are the possibilities:

all
     Suppress everything possible.

checksum
     Suppress mismatched font checksum warnings.

lostchar
     Suppress warnings when a character is missing from a font that a DVI or VF file tries to typeset.

none
     Don't suppress any warnings.

readable
     Suppress warnings about attempts to access a file whose permissions render it unreadable.

special
     Suppresses warnings about an unimplemented or unparsable \special command.

tex-hush.c defines the function that checks the variable value.  Each driver implements its own checks where appropriate.

Programming
***********

This chapter is for programmers who wish to use Kpathsea. See Introduction, for the conditions under which you may do so.

Programming overview
====================

Aside from this manual, your best source of information is the source to the programs I've modified to use Kpathsea (see Introduction).  Of those, Dviljk is probably the simplest, and hence a good place to start. Xdvik adds VF support and the complication of X resources.  Dvipsk adds the complication of its own config files.  Web2c is source code I also maintain, so it uses Kpathsea rather straightforwardly, but is of course complicated by the Web to C translation.  Finally, Kpsewhich is a small utility program whose sole purpose is to exercise the main path-searching functionality.

Beyond these examples, the .h files in the Kpathsea source describe the interfaces and functionality (and of course the .c files define the actual routines, which are the ultimate documentation). pathsearch.h declares the basic searching routine. tex-file.h and tex-glyph.h define the interfaces for looking up particular kinds of files.  In view of the way the headers depend on each other, it is recommended to use #include <kpathsea/kpathsea.h>, which includes every Kpathsea header.

If you want to include only specific headers, you should still consider including kpathsea/config.h before including any other Kpathsea header, as it provides symbols used in the other headers.  Note that kpathsea/config.h includes kpathsea/c-auto.h, which is generated by Autoconf.

The library provides no way for an external program to register new file types: tex-file.[ch] must be modified to do this. For example, Kpathsea has support for looking up Dvips config files, even though no program other than Dvips will likely ever want to do so.  I felt this was acceptable, since along with new file types should also come new defaults in texmf.cnf (and its descendant paths.h), since it's simplest for users if they can modify one configuration file for all kinds of paths.

Kpathsea does not parse any formats itself; it barely opens any files. Its primary purpose is to return filenames.  The GNU font utilities does contain libraries to read TFM, GF, and PK files, as do the programs above, of course.

Calling sequence
================

The typical way to use Kpathsea in your program goes something like this:

 1. Call kpse_set_program_name with argv[0] as the first argument; the second argument is a string or NULL.  The second argument is used by Kpathsea as the program name for the .PROGRAM feature of config files (see Config files). If the second argument is NULL, the value of the first argument is used.  This function must be called before any other use of the Kpathsea library.

     If necessary, kpse_set_program_name sets the global variables program_invocation_name and program_invocation_short_name. These variables are used in the error message macros defined in kpathsea/lib.h.  It sets the global variable kpse_program_name to the program name it uses.  It also initializes debugging options based on the environment variable KPATHSEA_DEBUG (if that is set).  Finally, it sets the variables SELFAUTOLOC, SELFAUTODIR and SELFAUTOPARENT to the location, parent and grandparent directory of the executable, removing . and .. path elements and resolving symbolic links. These are used in the default configuration file to allow people to invoke TeX from anywhere, specifically from a mounted CD-ROM.  (You can use --expand-var=\$SELFAUTOLOC, etc., to see the values finds.)

 2. The kpse_set_progname is deprecated.  A call to kpse_set_progname with argv[0] is equivalent to a call of kpse_set_program_name with first argument argv[0] and second argument NULL.  The function is deprecated because it cannot ensure that the .PROGRAM feature of config files will always work (see Config files).

 3. Set debugging options. See Debugging.  If your program doesn't have a debugging option already, you can define one and set kpathsea_debug to the number that the user supplies (as in Dviljk and Web2c), or you can just omit this altogether (people can always set KPATHSEA_DEBUG).  If you do have runtime debugging already, you need to merge Kpathsea's options with yours (as in Dvipsk and Xdvik).

 4. If your program has its own configuration files that can define search paths, you should assign those paths to the client_path member in the appropriate element of the kpse_format_info array.  (This array is indexed by file type; see tex-file.h.)  See resident.c in Dvipsk for an example.

 5. Call kpse_init_prog (see proginit.c). It's useful for the DVI drivers, at least, but for other programs it may be simpler to extract the parts of it that actually apply.  This does not initialize any paths, it just looks for (and sets) certain environment variables and other random information.  (A search path is always initialized at the first call to find a file of that type; this eliminates much useless work, e.g., initializing the BibTeX search paths in a DVI driver.)

 6. The routine to actually find a file of type FORMAT is kpse_find_FORMAT, defined in tex-file.h. These are macros that expand to a call to kpse_find_file.  You can call, say, kpse_find_tfm after doing only the first of the initialization steps above---Kpathsea automatically reads the texmf.cnf generic config files, looks for environment variables, and does expansions at the first lookup.

 7. To find PK and/or GF bitmap fonts, the routines are kpse_find_pk, kpse_find_gf and kpse_find_glyph, defined in tex-glyph.h. These return a structure in addition to the resultant filename, because fonts can be found in so many ways. See the documentation in the source.

 8. To actually open a file, not just return a filename, call kpse_open_file.  This function takes the name to look up and a Kpathsea file format as arguments, and returns the usual FILE *. It always assumes the file must exist, and thus will search the disk if necessary (unless the search path specified !!, etc.).  In other words, if you are looking up a VF or some other file that need not exist, don't use this.

Kpathsea also provides many utility routines. Some are generic: hash tables, memory allocation, string concatenation and copying, string lists, reading input lines of arbitrary length, etc. Others are filename-related: default path, tilde, and variable expansion, stat calls, etc. (Perhaps someday I'll move the former to a separate library.)

The c-*.h header files can also help your program adapt to many different systems.  You will almost certainly want to use Autoconf for configuring your software if you use Kpathsea; I strongly recommend using Autoconf regardless.  It is available from ftp://prep.ai.mit.edu/pub/gnu/.

Program-specific files
======================

Many programs will need to find some configuration files.  Kpathsea contains some support to make it easy to place them in their own directories.  The Standard TeX directory structure (see Introduction (A Directory Structure for TeX files)), specifies that such files should go into a subdirectory named after the program, like texmf/ttf2pk.

Two special formats, kpse_program_text_format and kpse_program_binary_format exist, which use .:$TEXMF/PROGRAM// as their compiled-in search path.  To override this default, you can use the variable PROGRAMINPUTS in the environment and/or texmf.cnf. That is to say, the name of the variable is constructed by converting the name of the program to upper case, and appending INPUTS.

The only difference between these two formats is whether kpse_open_file will open the files it finds in text or binary mode.

Programming with config files
=============================

You can (and probably should) use the same texmf.cnf configuration file that Kpathsea uses for your program.  This helps installers by keeping all configuration in one place.

To retrieve a value VAR from config files, the best way is to call kpse_var_value on the string VAR.  This will look first for an environment variable VAR, then a config file value. The result will be the value found or NULL.  This function is declared in kpathsea/variable.h.  For an example, see the shell_escape code in web2c/lib/texmfmp.c.

The routine to do variable expansion in the context of a search path (as opposed to simply retrieving a value) is kpse_var_expand, also declared in kpathsea/variable.h.  It's generally only necessary to set the search path structure components as explained in the previous section, rather than using this yourself.

If for some reason you want to retrieve a value only from a config file, not automatically looking for a corresponding environment variable, call kpse_cnf_get (declared in kpathsea/cnf.h) with the string VAR.

No initialization calls are needed.