gd_reference — retrieve or set the reference field for a Dirfile
const char *gd_reference(DIRFILE *dirfile, const char *field_code);
The gd_reference() function sets or retrieves the reference field (see dirfile(5)) associated with the dirfile specified by dirfile. If the field_code argument is non-NULL, the reference field for the dirfile will be set to the field specified. If field_code is NULL, the reference field is not modified. The field code should refer to a RAW field, and may not contain a representation suffix.
On success, gd_reference() returns the field code of the dirfile's reference field, which will be field_code, if field_code is non-NULL. If no RAW fields are defined in the dirfile, this function will return NULL, without raising an error. On error, NULL is returned and the dirfile error is set to a non-zero error value. Possible error values are:
- The specified dirfile was opened read-only.
- The library was unable to allocate memory.
- The field specified by field_code was not found.
- The supplied dirfile was invalid.
- The field specified by field_code was not a RAW field.
- The metadata of the primary format specification fragment (the file named format in the root dirfile directory) was protected from change.
The get_reference() function appeared in GetData-0.4.2. It took only one parameter (the DIRFILE), and returned the current reference field.
The dirfile_reference() function appeared in GetData-0.5.0.
In GetData-0.7.0, the dirfile_reference() function was renamed to gd_reference() and the get_reference() function was removed.
|25 December 2016||Version 0.10.0|