Explicit Cursor in Firebird PSQL

Explicit cursor is a new this in Firebird because it's only available in version 2. We can found this syntax in the release notes on Stored Procedure Language (PSQL) section. The example below is taken from that release notes

DECLARE RNAME CHAR(31);
DECLARE C CURSOR FOR ( SELECT RDB$RELATION_NAME FROM RDB$RELATIONS );
BEGIN
 OPEN C;
 WHILE (1 = 1) DO
 BEGIN
   FETCH C INTO :RNAME;
   IF (ROW_COUNT = 0) THEN
     LEAVE;
   SUSPEND;
 END
 CLOSE C;
END