xenial (3) gd_carrays.3.gz

NAME

       gd_carrays — 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);

DESCRIPTION

       The gd_carrays() function queries a dirfile(5) database specified by dirfile and returns a read-only list
       of values of the all CARRAY fields defined in the database,  after  type  conversion  to  the  data  type
       specified  by  return_type.   Notably,  this  list does not include /META subfields.  For a list of valid
       symbols to use for return_type, see the gd_get_carray(3) man page.

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

       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).
       The number of values in the array can be obtained from a call to gd_nfields_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 gd_carrays() is called again  with
       the  same  arguments,  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).

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

RETURN VALUE

       Upon successful completion, gd_carrays() returns 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 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.  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.  On
       error, gd_carrays() returns NULL and sets the dirfile error to a non-zero error  value.   Possible  error
       values 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.

       The dirfile error may be retrieved by calling gd_error(3).  A descriptive error string for the last error
       encountered can be obtained from a call to gd_error_string(3).

SEE ALSO

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