(kpathsea.info)File lookup

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Enter node , (file) or (file)node

4.2 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.  Example: given `foo.bar', look for
     `foo.bar.tex'.

  2. Search for NAME, and if necessary for alternative names found in
     the fontmaps.  Example: given `foo.bar', we also look for
     `foo.bar'.

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

   The order in which we search for "suffixed" name (item 1) or the
"as-is" name (item 2) is controlled by the `try_std_extension_first'
configuration value.  The default set in `texmf.cnf' is true, since
common suffixes are already recognized: `babel.sty' will only look for
`babel.sty', not `babel.sty.tex', regardless of this setting.

   When the suffix is unknown (e.g., `foo.bar'), both names are always
tried; the difference is the order in which they are tried.

   `try_std_extension_first' only affects names being looked up which
*already* have an extension.  A name without an extension (e.g., `tex
story') will always have an extension added first.

   This algorithm is implemented in the routine `kpathsea_find_file' in
`kpathsea/tex-file.c'.  You can watch it in action with the debugging
options (Note: Debugging).