NAME

       gd_carrays, gd_mcarrays — retrieve a list of CARRAY values from a Dirfile

SYNOPSIS

       #include <getdata.h>

       const gd_carray_t *gd_carrays(DIRFILE *dirfile, gd_type_t return_type);

       const gd_carray_t *gd_mcarrays(DIRFILE *dirfile, const char *parent, gd_type_t
              return_type);

DESCRIPTION

       The gd_carrays() function queries a dirfile(5) database specified by dirfile and generates
       a  read-only  list  of  values of the all top-level CARRAY fields defined in the database,
       after type conversion to the data type specified by return_type.   For  a  list  of  valid
       symbols to use for return_type, see the gd_get_carray(3) manual page.

       The  gd_mcarrays()  function  behaves  similarly,  but  creates a list of values of CARRAY
       subfields under the parent field parent.

       The dirfile argument must point to a valid DIRFILE object previously created by a call  to
       gd_open(3).

       A   corresponding   list   of   names   for  these  fields  may  be  obtained  by  calling
       gd_field_list_by_type(3) or gd_mfield_list_by_type(3).

RETURN VALUE

       Upon successful completion, gd_carrays() and gd_mcarrays(3) return a pointer to  an  array
       of  gd_carray_t  objects  containing  the values of all the CARRAYs defined in the dirfile
       database.  The gd_carray_t structure is defined as:

              typedef struct {
                size_t       n;              /* array_len */
                void        *d;              /* CARRAY data */
              } gd_carray_t;

       where n specifies the length of the CARRAY data, and d is an  array  of  the  data  values
       themselves. If return_type was GD_NULL, d will be NULL.  Otherwise, the caller should cast
       the void pointer to a type  appropriate  for  the  return_type  specified.   The  list  is
       terminated by an end-of-list marker consisting of a gd_carray_t item with n set to zero.

       If  no  CARRAYs are defined in the database, a list containing only the end-of-list marker
       is returned.

       The array returned will be de-allocated by a call to gd_close(3) and  should  not  be  de-
       allocated  by the caller.  The list returned should not be assumed to be in any particular
       order, except that it is guaranteed to be in the same order as the list of  CARRAY  fields
       returned  by  gd_field_list_by_type(3) or gd_mfield_list_by_type(3).  The number of values
       in   the   array   can   be   obtained   from   a   call   to   gd_nfields_by_type(3)   or
       gd_nmfields_by_type(3).

       The  caller  may  not  modify any values in the array, nor the array itself.  Doing so may
       cause database corruption.  The pointer returned is guaranteed to be valid only until  the
       function  is  called  again,  or  until  the  dirfile's  metadata  is modified (by adding,
       modifying or deleting an entry),  or  until  the  array  is  de-allocated  by  a  call  to
       gd_close(3) or gd_discard(3).

       On error, gd_carrays() returns NULL and stores a negative-valued error code in the DIRFILE
       object which may be retrieved by a subsequent call to gd_error(3).  Possible  error  codes
       are:

       GD_E_ALLOC
               The library was unable to allocate memory.

       GD_E_BAD_DIRFILE
               The supplied dirfile was invalid.

       GD_E_BAD_TYPE
               The return_type specified was invalid.

       GD_E_INTERNAL_ERROR
               An  internal error occurred in the library while trying to perform the task.  This
               indicates a bug in the  library.   Please  report  the  incident  to  the  GetData
               developers.

       A descriptive error string for the error may be obtained by calling gd_error_string(3).

HISTORY

       The gd_carrays() and gd_mcarrays() functions appeared in GetData-0.7.0.

SEE ALSO

       dirfile(5),  gd_error(3),  gd_error_string(3), gd_field_list_by_type(3), gd_get_carray(3),
       gd_mfield_list_by_type(3), gd_nfields_by_type(3) gd_nmfields_by_type(3) gd_open(3)