gd_mcarrays(3) GETDATA gd_mcarrays(3)NAME
gd_constants — retrieve a list of CARRAY values from a dirfile
SYNOPSIS
#include <getdata.h>
const gd_carray_t *gd_mcarrays(DIRFILE *dirfile, const char *parent,
gd_type_t return_type);
DESCRIPTION
The gd_mcarrays() function queries a dirfile(5) database specified by
dirfile and returns a read-only list of values of the all CARRAY
metafields for the supplied parent field, 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) 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_mfield_list_by_type(3). The number of values in the array can be
obtained from a call to gd_nmfields_by_type(3).
The caller may not modify any values in the array, nor the array it‐
self. Doing so may cause database corruption. The pointer returned is
guaranteed to be valid only until gd_mcarrays() is called again, or un‐
til the dirfile's metadata is modified (by adding, modifying or delet‐
ing 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 call‐
ing gd_field_list_by_type(3).
RETURN VALUE
Upon successful completion, gd_mcarrays() 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 termi‐
nated 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_mcarrays() 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_CODE
The supplied parent field code was not found, or referred to a
metafield itself.
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 per‐
form 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 descrip‐
tive error string for the last error encountered can be obtained from a
call to gd_error_string(3).
SEE ALSOdirfile(5), gd_carrays(3), gd_error(3), gd_error_string(3), gd_get_car‐
ray(3), gd_mfield_list_by_type(3), gd_nmfields_by_type(3), gd_open(3)Version 0.7.0 19 August 2011 gd_mcarrays(3)
