Provided by: gperf_3.0.3-1ubuntu1_amd64 bug

NAME

       gperf - generate a perfect hash function from a key set

SYNOPSIS

       gperf [OPTION]... [INPUT-FILE]

DESCRIPTION

       GNU 'gperf' generates perfect hash functions.

       If  a  long option shows an argument as mandatory, then it is mandatory for the equivalent
       short option also.

   Output file location:
       --output-file=FILE Write output to specified file.

       The results are written to standard output if no output file is specified or if it is -.

   Input file interpretation:
       -e, --delimiters=DELIMITER-LIST
              Allow user to provide a string containing delimiters used to separate keywords from
              their attributes.  Default is ",".

       -t, --struct-type
              Allows  the  user  to include a structured type declaration for generated code. Any
              text before %% is considered part of the type declaration. Key words and additional
              fields may follow this, one group of fields per line.

       --ignore-case
              Consider  upper  and  lower  case  ASCII characters as equivalent. Note that locale
              dependent case mappings are ignored.

   Language for the output code:
       -L, --language=LANGUAGE-NAME
              Generates code in the specified language.  Languages  handled  are  currently  C++,
              ANSI-C, C, and KR-C. The default is C.

   Details in the output code:
       -K, --slot-name=NAME
              Select name of the keyword component in the keyword structure.

       -F, --initializer-suffix=INITIALIZERS
              Initializers for additional components in the keyword structure.

       -H, --hash-function-name=NAME
              Specify name of generated hash function. Default is 'hash'.

       -N, --lookup-function-name=NAME
              Specify name of generated lookup function. Default name is 'in_word_set'.

       -Z, --class-name=NAME
              Specify name of generated C++ class. Default name is 'Perfect_Hash'.

       -7, --seven-bit
              Assume 7-bit characters.

       -l, --compare-lengths
              Compare  key  lengths  before  trying a string comparison. This is necessary if the
              keywords contain NUL bytes. It  also  helps  cut  down  on  the  number  of  string
              comparisons made during the lookup.

       -c, --compare-strncmp
              Generate comparison code using strncmp rather than strcmp.

       -C, --readonly-tables
              Make the contents of generated lookup tables constant, i.e., readonly.

       -E, --enum
              Define  constant values using an enum local to the lookup function rather than with
              defines.

       -I, --includes
              Include the necessary system include file <string.h> at the beginning of the code.

       -G, --global-table
              Generate the static table of keywords as a  static  global  variable,  rather  than
              hiding it inside of the lookup function (which is the default behavior).

       -P, --pic
              Optimize  the  generated table for inclusion in shared libraries.  This reduces the
              startup time of programs using a shared library containing the generated code.

       -Q, --string-pool-name=NAME
              Specify  name  of  string  pool  generated  by  option  --pic.   Default  name   is
              'stringpool'.

       --null-strings
              Use NULL strings instead of empty strings for empty keyword table entries.

       -W, --word-array-name=NAME
              Specify name of word list array. Default name is 'wordlist'.

       --length-table-name=NAME
              Specify name of length table array. Default name is 'lengthtable'.

       -S, --switch=COUNT
              Causes  the generated C code to use a switch statement scheme, rather than an array
              lookup table.  This can lead to a reduction in both time and space requirements for
              some  keyfiles.  The  COUNT  argument  determines  how  many  switch statements are
              generated.  A value of 1 generates 1 switch containing all the elements, a value of
              2  generates  2  tables  with 1/2 the elements in each table, etc. If COUNT is very
              large, say 1000000, the generated C code does a binary search.

       -T, --omit-struct-type
              Prevents the transfer of the type declaration to the output file. Use  this  option
              if the type is already defined elsewhere.

   Algorithm employed by gperf:
       -k, --key-positions=KEYS
              Select  the  key  positions used in the hash function.  The allowable choices range
              between 1-255, inclusive.  The positions are separated by  commas,  ranges  may  be
              used,  and  key  positions  may  occur  in any order.  Also, the meta-character '*'
              causes the generated hash function to consider ALL key positions, and  $  indicates
              the "final character" of a key, e.g., $,1,2,4,6-10.

       -D, --duplicates
              Handle  keywords  that  hash to duplicate values. This is useful for certain highly
              redundant keyword sets.

       -m, --multiple-iterations=ITERATIONS
              Perform multiple choices of the -i and -j values, and choose the best results. This
              increases the running time by a factor of ITERATIONS but does a good job minimizing
              the generated table size.

       -i, --initial-asso=N
              Provide an initial value for the associate values array. Default is 0. Setting this
              value larger helps inflate the size of the final table.

       -j, --jump=JUMP-VALUE
              Affects  the  "jump value", i.e., how far to advance the associated character value
              upon collisions. Must be an odd number, default is 5.

       -n, --no-strlen
              Do not include the length of the keyword when computing the hash function.

       -r, --random
              Utilizes randomness to initialize the associated values table.

       -s, --size-multiple=N
              Affects the size of the generated hash table. The numeric argument N indicates "how
              many times larger or smaller" the associated value range should be, in relationship
              to the number of keys, e.g. a value of 3 means "allow the maximum associated  value
              to  be  about 3 times larger than the number of input keys". Conversely, a value of
              1/3 means "make the maximum associated value about 3 times smaller than the  number
              of  input  keys".  A  larger  table  should  decrease  the  time  required  for  an
              unsuccessful search, at the expense of extra table space. Default value is 1.

   Informative output:
       -h, --help
              Print this message.

       -v, --version
              Print the gperf version number.

       -d, --debug
              Enables the debugging option (produces verbose output to the standard error).

AUTHOR

       Written by Douglas C. Schmidt and Bruno Haible.

REPORTING BUGS

       Report bugs to <bug-gnu-gperf@gnu.org>.

COPYRIGHT

       Copyright © 1989-1998, 2000-2004, 2006-2007 Free Software Foundation, Inc.
       This is free software; see the source for copying conditions.  There is NO  warranty;  not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       The full documentation for gperf is maintained as a Texinfo manual.  If the info and gperf
       programs are properly installed at your site, the command

              info gperf

       should give you access to the complete manual.