The sample udf_blob is included in a precompiled dynamic library called libv4apiex (extension is platform-dependent). Its implementation is in the samples directory in udf_blob.cxx.
ITo declare the table UDF to the server, issue:
CREATE PROCEDURE udf_blob( IN data long varchar, letter char(1) )
RESULT ( c1 BIGINT )
EXTERNAL NAME 'udf_blob@libv4apiex'
Select rows from the table UDF:
set temporary option Enable_LOB_Variables = 'On';
create variable testblob long varchar;
set testblob = 'aaaaaaaaaabbbbbbbbbbbb';
select * from udf_blob(testblob, 'a');
The supplied string contains the letter "a" 10 times.