Some info of sendto(), recvfrom()

[N100CCH0 at TWNITRI1.BITNET]

We have SunLink OSI installed in our SPARC station 1.  We use OSI
sock_dgram system interface to CLNS.

The program I wrote is following page 115, 116 in chapter 6 - the OSI
sock_dgram system interface in the SunLink OSI programmer's Guide.  The
program works fine.

The problem occured when I tried to replace sendmsg() by sendto(), replace
recvmsg() by recvfrom() in the same program.  The error message is
"unreachable network".

I really appreciate if anyone can tell me how to use sendto and recvfrom
in this program.

Thanks in advance.