NAME¶
gd_mfield_list — retrieve a list of fields in a dirfile
SYNOPSIS¶
#include <getdata.h>
const char **gd_mfield_list(DIRFILE
*dirfile, const char *parent);
DESCRIPTION¶
The
gd_mfield_list() function queries a
dirfile(5) database specified by
dirfile and returns a read-only list of names of the all metafields for
the specified parent field in the database.
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. The array is terminated by a NULL
pointer. The number of strings in the array can be obtained from a call to
gd_nmfields(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_mfield_list() is called again with the same arguments,
or until the array is de-allocated by a call to
gd_close(3).
RETURN VALUE¶
Upon successful completion,
gd_mfield_list() returns a pointer to an
array of strings containing the names of all the metafields of the given
parent. 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.
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_mfield_list_by_type(3),
gd_mvector_list(3),
gd_nfields(3)
