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gawk: Array Functions

 
 16.4.11.2 Array Functions
 .........................
 
 The following functions relate to individual array elements:
 
 'awk_bool_t get_element_count(awk_array_t a_cookie, size_t *count);'
      For the array represented by 'a_cookie', place in '*count' the
      number of elements it contains.  A subarray counts as a single
      element.  Return false if there is an error.
 
 'awk_bool_t get_array_element(awk_array_t a_cookie,'
 '                             const awk_value_t *const index,'
 '                             awk_valtype_t wanted,'
 '                             awk_value_t *result);'
      For the array represented by 'a_cookie', return in '*result' the
      value of the element whose index is 'index'.  'wanted' specifies
      the type of value you wish to retrieve.  Return false if 'wanted'
      does not match the actual type or if 'index' is not in the array
      (⇒Table 16.1 table-value-types-returned.).
 
      The value for 'index' can be numeric, in which case 'gawk' converts
      it to a string.  Using nonintegral values is possible, but requires
      that you understand how such values are converted to strings (⇒
      Conversion); thus, using integral values is safest.
 
      As with _all_ strings passed into 'gawk' from an extension, the
      string value of 'index' must come from 'gawk_malloc()',
      'gawk_calloc()', or 'gawk_realloc()', and 'gawk' releases the
      storage.
 
 'awk_bool_t set_array_element(awk_array_t a_cookie,'
 '                             const awk_value_t *const index,'
 '                             const awk_value_t *const value);'
      In the array represented by 'a_cookie', create or modify the
      element whose index is given by 'index'.  The 'ARGV' and 'ENVIRON'
      arrays may not be changed, although the 'PROCINFO' array can be.
 
 'awk_bool_t set_array_element_by_elem(awk_array_t a_cookie,'
 '                                     awk_element_t element);'
      Like 'set_array_element()', but take the 'index' and 'value' from
      'element'.  This is a convenience macro.
 
 'awk_bool_t del_array_element(awk_array_t a_cookie,'
 '                             const awk_value_t* const index);'
      Remove the element with the given index from the array represented
      by 'a_cookie'.  Return true if the element was removed, or false if
      the element did not exist in the array.
 
    The following functions relate to arrays as a whole:
 
 'awk_array_t create_array(void);'
      Arrays:: for a discussion of how to create a new array and add
      elements to it.
 
 'awk_bool_t clear_array(awk_array_t a_cookie);'
      Clear the array represented by 'a_cookie'.  Return false if there
      was some kind of problem, true otherwise.  The array remains an
      array, but after calling this function, it has no elements.  This
      is equivalent to using the 'delete' statement (⇒Delete).
 
 'awk_bool_t flatten_array_typed(awk_array_t a_cookie,'
 '                               awk_flat_array_t **data,'
 '                               awk_valtype_t index_type,'
 '                               awk_valtype_t value_type);'
      For the array represented by 'a_cookie', create an
      'awk_flat_array_t' structure and fill it in with indices and values
      of the requested types.  Set the pointer whose address is passed as
      'data' to point to this structure.  Return true upon success, or
      false otherwise.  ⇒Flattening Arrays, for a discussion of
      how to flatten an array and work with it.
 
 'awk_bool_t flatten_array(awk_array_t a_cookie, awk_flat_array_t **data);'
      For the array represented by 'a_cookie', create an
      'awk_flat_array_t' structure and fill it in with 'AWK_STRING'
      indices and 'AWK_UNDEFINED' values.  This is superseded by
      'flatten_array_typed()'.  It is provided as a macro, and remains
      for convenience and for source code compatibility with the previous
      version of the API.
 
 'awk_bool_t release_flattened_array(awk_array_t a_cookie,'
 '                                   awk_flat_array_t *data);'
      When done with a flattened array, release the storage using this
      function.  You must pass in both the original array cookie and the
      address of the created 'awk_flat_array_t' structure.  The function
      returns true upon success, false otherwise.
 
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