I have written a code in c, it works and now I want to implement it in Monetdb. 1) should I append the code in /sql/backends/monet5/UDF/udf.c file? 2) I have gone through udf.c, but still not sure how implement my c code there. I do not know C, just wanted to implement simple code. Can anyone help me adapting it to UDF? I want a function like BAnd(a.chunk, b.chunk), and instead of {"10101011"} in foo and bar, I want values of the columns. #include<stdio.h> main (){ const char foo[] = {"10101011"}; const char bar[] = {"01110111"}; int counter; float result; int strlen = sizeof(foo)/sizeof(foo[0])-1; for (int i=0; i < strlen; i++) { if (foo[i] == bar[i]) { counter++; } } result = (float)counter / strlen; printf("%d::%d::%f", counter, strlen, result); return 0; }