How to add our functions in postgres

Hi,
I have to add a function in varlena.c named
btcasecmp(PG_FUNCTION_ARG) ,
so what other information I have to add in source.
I know little bit of it,
I have added that function in
src/backend/utils/fmgrtab.c and assign a new oid but when I installed that 
function definition is not appearing in the table "pg_amproc",
So I want to know what other information I have to add so that I can call 
my function using oid.

Thanks and regards,
Sandeep

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| Sandeep Satpal |
| M.Tech Student |
| Lab 212 KReSIT |
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