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When to Use the Error
Message Service
At the level of applications code the Error Reporting System, ERR, exclusively
should be used for error reporting.
Within environment subroutine libraries the rule is to use calls to EMS unless
it is necessary to deliver error messages to the user (i.e. by
calls to
ERR_FLUSH).
A subroutine library must use one or other of these error reporting
libraries exclusively: i.e. if EMS calls are used within a
subroutine library, they must be used exclusively throughout the library -
no calls to ERR routines are allowed.
Furthermore, if ERR calls are used to report errors within a subroutine
library, say because calls to ERR_FLUSH are required during
interaction with
the user, then it must be understood that this subroutine library exists at a
hierarchical level above the environment system software.
This subroutine library cannot then be called from other libraries purporting
to exist at lower levels within the subroutine hierarchy -
to do so could result in unpredictable behaviour when an error occurs.
Next: Reporting Errors
Up: EMS Error Message Service
Previous: Introduction
EMS Error Message Service
Starlink System Note 4
P C T Rees
A J Chipperfield
28 September 2001
E-mail:ussc@star.rl.ac.uk
Copyright © 2001 Council for the Central Laboratory of the Research
Councils