GNU `gperf' generates perfect hash functions. Usage: ../src/gperf [OPTION]... [INPUT-FILE] If a long option shows an argument as mandatory, then it is mandatory for the equivalent short option also. Input file interpretation: -e, --delimiters=DELIMITER-LIST Allow user to provide a string containing delimiters used to separate keywords from their attributes. Default is ",\n". -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. 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-fn-name=NAME Specify name of generated hash function. Default is `hash'. -N, --lookup-fn-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. -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 at the beginning of the code. -G, --global 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). -W, --word-array-name=NAME Specify name of word list array. Default name is `wordlist'. -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 1-126, 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. -l, --compare-strlen Compare key lengths before trying a string comparison. This helps cut down on the number of string comparisons made during the lookup. -D, --duplicates Handle keywords that hash to duplicate values. This is useful for certain highly redundant keyword sets. -f, --fast=ITERATIONS Generate the gen-perf.hash function ``fast''. This decreases gperf's running time at the cost of minimizing generated table size. The numeric argument represents the number of times to iterate when resolving a collision. `0' means ``iterate by the number of keywords''. -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. -o, --occurrence-sort Reorders input keys by frequency of occurrence of the key sets. This should decrease the search time dramatically. -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 -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). Report bugs to .