recvfrom returns -1

I ported a process over from QNX4 to QNX6 with minimal changes. The process sits in a loop waiting for incoming UDP packets using recvfrom. However, when a packet comes in the call fails with “message too long” (even for small test packets). I tried increasing the buffer size, but to no avail. Any suggestions on this?

problem solved - one of the parameters was uninitialized (guess QNX4 allows it, but not QNX6).