gd_reference(3)

NAME

gd_reference—retrieve or set the reference field for a Dirfile

SYNOPSIS

#include <getdata.h>

const char *gd_reference(DIRFILE *dirfile, const char *field_code);

DESCRIPTION

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.

RETURN VALUE

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:

GD_E_ACCMODE: The specified dirfile was opened read-only.
GD_E_ALLOC: The library was unable to allocate memory.
GD_E_BAD_CODE: The field specified by field_code was not found.
GD_E_BAD_DIRFILE: The supplied dirfile was invalid.
GD_E_BAD_FIELD_TYPE: The field specified by field_code was not a RAW field.
GD_E_PROTECTED: The metadata of the primary format specification fragment (the file named format in the root dirfile directory) was protected from change.

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).

HISTORY

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.