NAME¶
gd_mstrings — retrieve a list of string values from a dirfile
SYNOPSIS¶
#include <getdata.h>
const char **gd_mstrings(DIRFILE *dirfile,
const char *parent);
DESCRIPTION¶
The
gd_mstrings() function queries a
dirfile(5) database specified by
dirfile and returns a read-only list of values of the all
STRING
type metafields for the supplied
parent field.
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
STRING fields returned by
gd_mfield_list_by_type(3). The array is terminated by a NULL pointer.
The number of strings in the array can be obtained from a call to
gd_nmfields_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_mstrings() is called again with the same arguments, 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_mfield_list_by_type(3).
RETURN VALUE¶
Upon successful completion,
gd_mstrings() returns a pointer to an array
of strings containing the values of all the
STRING metafields for the
specified parent field. 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_nmfields_by_type(3),
gd_strings(3)