Provided by: zlibc_0.9j-7_i386 bug


       zlibc.conf - zlibc’s configuration file


       This  manpage  has  been  automatically  generated from zlibc’s texinfo
       documentation.  However, this process is only approximative,  and  some
       items,  such as crossreferences, footnotes and indices are lost in this
       translation  process.   Indeed,  this   items   have   no   appropriate
       representation  in  the  manpage format.  Thus I strongly advise you to
       use the original texinfo doc.

       *      To generate a printable copy  from  the  texinfo  doc,  run  the
              following commands:

                     ./configure; make dvi; dvips zlibc.dvi

       *      To generate a html copy,  run:

                     ./configure; make html

              A       premade       html       can      be      found      at:

       *      To generate an info copy (browsable  using  emacs’  info  mode),

                     ./configure; make info

       The  texinfo doc looks most pretty when printed or as html.  Indeed, in
       the info version certain examples are difficult  to  read  due  to  the
       quoting conventions used in info.


       To  get its configuration, zlibc first looks into the file described by
       the environment variable LD_ZLIB_CONFFILE (if any), then in ‘~/.zlibrc’
       and  finally in ‘/usr/local/etc/zlibc.conf’ (‘/etc/zlibc.conf’ on Linux
       ).  If the desired information is found in neither of these files,  the
       compiled-in  defaults  are used.  It is possible to supply only part of
       the needed information in the configuration files. In  that  case,  the
       missing  information  is  retrieved from the compiled-in defaults. This
       allows you to have really small runtime configuration files, which only
       list   the  differences  between  the  desired  configuration  and  the
       compiled-in configuration.

       If an error occurs while parsing one of the  configuration  files,  the
       offending file is skipped, and the search continues with the next file.
       However, no error message is printed unless the environmental  variable
       LD_ZLIB_VERBOSE is turned on (i.e. set to 1 or to on ).

       If  two files contain contradictory information, the information in the
       file which is scanned first is retained (usually ‘~/.zlibrc’).  If  any
       flags  have  been  set  or  unset  using environmental variables, these
       settings override the flags specified in the configuration files.

       The configuration files are read by each  process.  For  each  process,
       they  are  read  at  most  once,  at  the time when zlibc is first used
       (attempt to access a compressed file). Afterwards they  are  cached  in
       the process’s virtual memory.  Thus, changing zlibc configuration files
       doesn’t generally have any effect on already running processes.

Overall structure

       The zlibrc files consist of two sections: A commands section (‘Commands
       line flags’) and a class definition section (‘Class section’).

       The commands section describes how zlibc should behave depending on the
       executable that it was  called  from.   Several  commands  are  grouped
       together into command classe.

       The   class  definition  section  describes  how  zlibc  should  behave
       depending on the class of the command and the datafile opened.

       The configuration file may contain comments in both sections: a comment
       starts with a hash (#) and stops at the end of the line.

       Dashes (-) and underbars (_) may be used indifferently in all keywords.

Commands section

   General syntax of the commands section
       The format for a line in the "commands" section is as follows:

       commands "cmd1" [ ... "cmdn" ] use flags "class"

       In this line, the cmd1 ... cmdn  are  the  basenames  of  the  programs
       (commands)  for which this line should apply.  The basename is the name
       without the path, i.e. ls instead of  /usr/bin/ls.  The  command  names
       should  be  enclosed  in  quotes.  You may also use the keyword default
       (without quotes) to match all commands.

       The  flags  describe  those  aspects  of  zlibc’s  behaviour  that  are
       independant from the datafile which is being accessed. These flags come
       in pairs.  The flags need not to be listed on a single  commands  line,
       they   may   occur   in  several  places,  even  in  several  different
       configuration files (for instance one in  /etc/zlibc.conf  and  another
       one in ~/.zlibrc.

       If  two  contradictory  flags are found in the configuration files, the
       one which is seen first is taken.

       If on the other hand a  certain  flag  is  not  found  at  all  in  the
       configuration  files,  the  compiled-in  default for this flag is used.
       This is usually the second flag of  each  pair,  described  below  (see
       section  Commands line flags).

       These flags can all be overridden by environmental variables.  When the
       corresponding environmental variable is set to 1 or to  on,  the  first
       flag  is  used,  when  it  is set to 0 or to off.  If the environmental
       variables is set to neither of these 4 values, it is ignored).

       The class names the commands class that these commands belong to.   If,
       for a given command, two commands lines give different classes, the one
       which is seen first is taken. No union of classes is made, the  classes
       are  always treated as a whole. Thus, if you want to make a change to a
       command class, you need to describe it in its entirety.

       The following example says that the tar, cpio,  pax,  cp  and  mv  show
       compressed  files  in a directory listing (readdir_compr flag), and are
       of class generic_safe.

          commands "tar" "cpio" "pax" "cp" "mv" use readdir_compr "generic_safe"

       The class generic_safe would then need to be described further  in  the
       class section.

   Available commands line flags
       This  section describes the flags which can be used on a commands line.
       All these flags come in pairs.

       The table below describes each of these pairs.  The first word  in  the
       header  of  each  item  is the non-default flag, the second word is the
       default flag, and the third word is the environmental variable by which
       you  can  override  the  settings from the configuration files. If this
       environmental variable is turned on (set to 1), the non-default (first)
       flag  is  taken,  if  it is turned off (set to 0), the default (second)
       flag is taken.

       disable / enable / LD_ZLIB_DISAB
              The disable  flag  disables  zlibc  for  the  programs  on  this
              commands line.  This is useful for compression and uncompression
              utilities.  Without this flag, gunzip would  not  work  anymore,
              because  it  would  think  that  the  uncompressed  file  exists
              already, and it would refuse to overwrite this file.

       disable_child / enable_child / LD_ZLIB_DISAB_CHILD
              The disable_child flag disables zlibc for the  programs  started
              by  programs  on  this  commands  line.  This  is implemented by
              removeing all occurrences of uncompress.o  from  the  LD_PRELOAD
              environment  variable. This function is useful for programs such
              as xemacs, in order to make sure that all  launched  subprograms
              return results consistent with emacs itself (directory listings,

       readdir_compr / readdir_uncompr / LD_ZLIB_READDIR
              The readdir function shows the  uncompressed  files  (i.e.  with
              their  trailing  .gz  extension)  when the readdir_compr flag is
              set, and the compressed files otherwise.

       verbose / silent / LD_ZLIB_VERBOSE
              When verbose is set, zlibc prints informational messages.

       unlink / no_unlink / LD_ZLIB_UNLINK
              If the unlink flag is set, and if  the  user  program  tries  to
              unlink  a  virtual  (uncompressed)  file, the package translates
              this call into unlinking the real file. If the no_unlink flag is
              set,   requests  to  unlink  virtual  (uncompressed)  files  are
              silently ignored.

Class section

       A command class definition describes those aspects of zlibc’s  behavior
       that  depend  on  the  name  of  the  datafile which is being accessed.
       Command classes are identified by a name which is matched  against  the
       class  parameter  from the commands.  The class name should be enclosed
       between quotes both in the commands line and in the class definition.

       The class section contains descriptions of  different  command  classes
       (i.e  descriptions  how  datafiles  should be uncompressed). Each class
       definition begins with a line of the following format:

       class "id"

       The class id is the same string as the one used in the  commands  line.
       The remaining lines of a class definition are as follows: [ [ criterion
       ] [ "name" ]] mode

       The following example shows the definition of the  class  used  for  X-

          # X uses tmp files in its own directories.
          class "X"
          subdir "/usr/X11R6" usetmpfile
          subdir "/usr/X386" usetmpfile
          subdir "/usr/lib/X11" usetmpfile

       This  says  that  all  compressed files who are in a subdirectory below
       ‘/usr/X11R6’, ‘/usr/X386’  or  ‘/usr/lib/X11’  are  decompressed  using
       temporary files (usetmpfile), and that files from other directories are
       decompressed using pipes (showpipe)

       The following examples illustrates a command class, named nopipe, which
       always  uses  temporary  files  for decompression # generic class which
       uses temp files for all files.  class "nopipe" usetmpfile

   File selection Criteria
       The criterion  describes what parts of the filename should match:

              The entire filename of the target data file must match name.

              The basename (filename without directory)  of  the  target  data
              file must match name.

              The  data  file  must  live  in the directory name.  If the user
              program opens the file with an absolute pathname, that  filename
              is  used  as  is.   If on the other hand the user program uses a
              relative pathname, zlibc uses the most direct path to  the  file
              (i.e. without symlinks).

              The  data  file must live in the directory name or in one of its
              subdirectories. If the user  program  opens  the  file  with  an
              absolute pathname, that filename is used as is.  If on the other
              hand the user program uses a relative pathname, zlibc  uses  the
              most direct path to the file (i.e. without symlinks).

              The  data  file’s  name  must  end  in name.  This is useful for
              selecting files according to their extension.

              The data file must live on the same  filesystem  as  name.  This
              criterion  can  for example be used for example to disable zlibc
              on a doublespaced filesystem (where zlibc would  be  redundant),
              or  to  switch  off  uncompressed  size  reporting  on  an ftpfs
              filesystems .

              All data files match. All class definitions must have a  default
              line,  and  this  default  line  must  be  the  last line of the
              definition. The default criterion needs no ’name’ parameter.

       all    All data files match. Unlike default, this line needs not to  be
              the  last  line of the class definitions. Thus it is possible to
              specify  several  all  lines  for  different  aspects  of  zlibc

       The  lines  of  each class definition are scanned in sequence, and, for
       each aspect, the first matching line is  adopted.   The  class  may  be
       defined  in another initialisation file, if this file is scanned later.
       The criterion parameter may be omitted if it can be  deduced  from  the
       name. In that case, the following heuristics are used:

       *      Names beginning with a dot are considered as suffix.

       *      Names  beginning  with  a slash, but not ending with a slash are
              considered as filename.

       *      Names beginning and  ending  with  a  slash  are  considered  as

       *      A missing name is considered as default.

       *      All the other names are considered as basename.