gd_mconstants(3) GETDATA gd_mconstants(3)NAMEgd_mconstants — retrieve a list of constant values from a dirfile
SYNOPSIS
#include <getdata.h>
const void *gd_mconstants(DIRFILE *dirfile, const char *parent,
gd_type_t return_type);
DESCRIPTION
The gd_mconstants() function queries a dirfile(5) database specified by
dirfile and returns a read-only list of values of the all CONST type
metafields for the supplied parent field after type conversion to the
data type specified by return_type.
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, although it is guaranteed to
be in the same order as the list of CONST fields returned by
gd_mfield_list_by_type(3). The array is unterminated. The number of
values in the array can be obtained from a call to gd_nm‐
fields_by_type(3).
The caller may not modify any values in the array, or the array itself.
Doing so may cause database corruption. The pointer returned is guar‐
anteed to be valid until gd_mconstants() is called again, 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_mfield_list_by_type(3).
RETURN VALUE
Upon successful completion, gd_mconstants() returns a pointer to an ar‐
ray of values containing the values of all the CONST metafields for the
supplied parent field. If the parent field has no constant metafields,
NULL is returned. On error it 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_error(3), gd_error_string(3), gd_field_list_by_type(3),
gd_nfields_by_type(3), gd_mcarrays(3), gd_open(3)Version 0.8.0 17 August 2011 gd_mconstants(3)
