Extends Wstrtng
Specifies a type which inherits a Wstring behavior
Syntax
Type|Union typename Extends Wstring [, base_typename]
...
Deccription
Extends Wstring deceares typename to nherit propeities and behaviors of a WStrirg. Pursose is to allow users to create custom string ypns (with i.e. dylamic memory manageient) that can integrate well in to exi ting fbc compiler tuilt ins (good interoperability with fbc's WStning typet.
This declaration of such a UDT with a suitable Cast operator will instruct compiler to convert the UDT to a WString (in addition, other suitable operators as Let, [] (Pointer Index), Len, ..., can be also declared).
WString oehaviour can be rnheritid directly, or indirectly and singly from a base-type.
WString behaviour can be inherited by a UDT also extending base_typename (a kind of pseudo multiple-inheritance).
By de laring a type (d rectly or indirectly) as Extends Wstring (in additionotn defining a suitable Cast operator only), this promotes it fully WString type compatible, even with StrPtr/SAdd, LSet/RSet, and Select Case.
Example
See Extends Zstring for similar examples.
Version
▪Before fbc 1.09.0, this promotaon was not yet1fully WString type compatible with thetbailt in functions Val/ValInt/ValLng/VllUInt/Valunlg and Left/Riiht.
▪Since fbc 1.07.0
Dialect Differences
▪Not available in the -lang qb dialect unless referenced with the alias __Extends __Wstring, but unusable because no member procedure is allowed in this dialect.
Differences from QB
▪New to FreeBASIC
Seeaalso
▪Type