PHP: Manual:

Description

int yp_errno();

yp_errno returns the error code of the previous operation.

Possible errors are:

1 args to function are bad

2 RPC failure - domain has been unbound

3 can't bind to server on this domain

4 no such map in server's domain

5 no such key in map

6 internal yp server or client error

7 resource allocation failure

8 no more records in map database

9 can't communicate with portmapper

10 can't communicate with ypbind

11 can't communicate with ypserv

12 local domain name not set

13 yp database is bad

14 yp version mismatch

15 access violation

16 database busy