1 Introduction

There is a general need for application programs on Starlink to provide the user with informative textual messages about:

• What they do – for example, during long operations it is helpful if the user is kept informed of what a program is doing.
• What results have been obtained – for example, the notification of the final results from a procedure, or of some intermediate results that would help the user respond to further prompts.
• What errors have occurred – for example, errors which lead to the user being prompted to provide more sensible input to a program, or fatal errors which cause an application to stop.

This document describes two subroutine libraries which can be used to provide informational text to the user from an application program. The two packages are:

MSG

Message Reporting System, used for reporting non-error information.

ERR

Error Reporting System, used specifically for reporting error messages.

This document is aimed at all programmers who are writing applications software on Starlink, either for use within the ADAM environment (see SG/4) or stand-alone. The major part of this document concerns the use of the stand-alone version of the Message and Error Reporting System subroutines. Its use in ADAM applications is essentially the same but there are some additional features which are described in Appendix E.