NAME¶
gd_field_list_by_type — retrieve a list of fields in a dirfile
SYNOPSIS¶
#include <getdata.h>
const char **gd_field_list_by_type(DIRFILE
*dirfile, gd_entype_t type);
DESCRIPTION¶
The
gd_field_list_by_type() function queries a
dirfile(5) database
specified by
dirfile and returns a read-only list of names of the all
fields of the indicated type which are defined in the database. Notably, this
list does not include /META subfields.
The
dirfile argument must point to a valid DIRFILE object previously
created by a call to
gd_open(3). The
type argument should be one
of the following symbols indicating the desired field type:
- GD_BIT_ENTRY, GD_CARRAY_ENTRY, GD_CONST_ENTRY,
GD_DIVIDE_ENTRY, GD_INDEX_ENTRY, GD_LINCOM_ENTRY,
GD_LINTERP_ENTRY, GD_MULTIPLY_ENTRY, GD_PHASE_ENTRY,
GD_POLYNOM_ENTRY, GD_RAW_ENTRY, GD_RECIP_ENTRY,
GD_SBIT_ENTRY, GD_STRING_ENTRY.
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. The array is terminated by a NULL
pointer. The number of fields in the array can be obtained from a call to
gd_nfields_by_type(3).
The caller may not modify any strings in the array, or the array itself. Doing
so may cause database corruption. The pointer returned is guaranteed to be
valid until
gd_field_list_by_type() is called again on the same DIRFILE
object with the same
type argument, or until the array is de-allocated
by a call to
gd_close(3).
For
CONST,
CARRAY, and
STRING field types, corresponding
lists of values for may be obtained by calling
gd_constants(3),
gd_carrays(3), or
gd_strings(3).
RETURN VALUE¶
Upon successful completion,
gd_field_list_by_type() returns a pointer to
an array of strings containing the names of all the fields defined in the
dirfile database of the specific type. 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_DIRFILE
- The supplied dirfile was invalid.
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_constants(3),
gd_error(3),
gd_error_string(3),
gd_field_list(3),
gd_mfield_list_by_type(3),
gd_nfields_by_type(3),
gd_strings(3)