|  |  |  | libuser Reference Manual |  | 
|---|---|---|---|---|
#define LU_VALUE_INVALID_ID char* lu_value_strdup (const GValue *value); gboolean lu_value_init_set_attr_from_string (GValue *value, const char *attr, const char *string, lu_error_t **error); void lu_value_init_set_id (GValue *value, id_t id); id_t lu_value_get_id (const GValue *value); int lu_values_equal (const GValue *a, const GValue *b);
Libuser entities store attribute values as GValue, which allows representing
any possible data type.  Only a few types are needed in practice; the only
types applications should hard-code are G_TYPE_LONG and G_TYPE_STRING
(G_TYPE_STRING can usually be used as a fallback for other number types).
The only currently used data types that are not conveniently supported using
the above types are uid_t and gid_t (which can be together represented in
id_t), because they can support values outside of the range of glong.  Helper
functions are provided to convert values between id_t and GValue, even if the
value is stored using G_TYPE_STRING.  The GValue types used for storing id_t
values are an internal implementation detail of libuser and applications should
not rely on them.
Values of each attribute are expected to have a specific type, documented in
the documentation of the specific attribute name.  Using other types (e.g.
using G_TYPE_STRING for LU_UIDNUMBER) is not allowed and results in undefined
behavior.. You can use lu_value_strdup() and
lu_value_init_set_attr_from_string() for conversion between strings and values
appropriate for a specific attribute.
#define LU_VALUE_INVALID_ID ((id_t)-1)
An id_t value that matches no valid user or group ID.
char* lu_value_strdup (const GValue *value);
Converts value, of any type used by libuser, to a string.  Preferable
to hard-coding checks for expected value types.
| 
 | value | 
| Returns : | string, should be freed by g_free() | 
gboolean lu_value_init_set_attr_from_string (GValue *value, const char *attr, const char *string, lu_error_t **error);
Initializes a zero-filled (uninitialized) value for storing a value of
attribute attr and sets it to the contents of string.  To see whether a
specific type is used for an attribute, see the documentation of that
attribute.
void lu_value_init_set_id (GValue *value, id_t id);
Initializes a zero-filled (uninitialized) value with an unspecified type and
sets it to id.
| 
 | GValue | 
| 
 | user or group ID. | 
id_t lu_value_get_id (const GValue *value);
Get the contents of value. value should be initialized by
lu_value_init_set_id() or use G_TYPE_LONG or G_TYPE_STRING.
If value does not contain a valid id_t value, LU_VALUE_INVALID_ID
is returned.
| 
 | GValue | 
| Returns : | ID value or LU_VALUE_INVALID_ID |