[SQL] Registring a C function in PostgreSQL

[Miguel González]

I have followed the instructions in the Bruje Momjian´s book to register a function, and i got this message:  ERROR:/load of file /home/postgres/ctof.so failed: /home/postgres/ctof.so ELF file´s phentsize not the expected size. What is going on? I have tried to get more documentation about how to use C functions in PostgreSQL, but I cant.  Many thanks in advance  Miguel