Internet

Introduction

The IYONIX pc has a 10/100/1000Mbit/s Ethernet Interface built in and an RJ45 connector on the back panel. RISC OS 5.01 is currently being supplied with Version 5 of the Internet stack is in ROM and this includes PPP and EtherK modules.

There has been some confusion about error numbers returned by Internet calls in RISC OS 5 although the behaviour is unchanged from RISC OS 3.50:

Error numbers used by DCI 4

The Internet module provided with RISC OS 5 uses the same version of the DCI (Device Control Interface) protocol that was introduced in RISC OS 3.50. Programmers using the DCI 4 version of the Internet module should note that the error codes returned by SockLib calls are different to those returned by the corresponding Socket_... SWIs.

When calling Internet SockLib routines any errors are normally indicated by a return value of -1 with the Internet error number in the errno global variable and error numbers are in the range 0 to 87 as documented under ERRNO in the RISC OS Programmer's Reference Manual (PRM) volume 5a (page 5a-380 of the printed copy).

However, when calling Internet routines as using the Socket_... SWI any errors are returned using the conventional RISC OS mechanism, i.e. the V (overflow) flag is set and R0 points to an error block. In this instance the error number in the error block is &20E00 greater than the Internet error number.

This is in accordance with the error mechanism described in the section The Internet module - SWI Calls in the PRM (page 5a-463 of the printed copy).

For example, the CONNECT call might return &24 in errno to indicate that a non-blocking connection is in progress, but the equivalent SWI call to Socket_Connect under the same circumstances would return &20E24.