XMM-Newton Science Analysis System


cal (cal-3.184) [xmmsas_20070308_1802-6.6.0]

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Error Handling

Error conditions can arise as a consequence of various circumstances:

• failure of operating system functions (e.g. file reading)
• out-of-boundary conditions (e.g. requesting PSF at energy for which no information is available)
• problem with calibration index mechanism
• conflicts between CAL state and type of requested calibration quantity (e.g., no energy-to-PI conversion for OM)
• others

The CAL uses the general SAS error handling strategy (see package error for details): An error condition can either be fatal or non-fatal. In the former case no corrective action can be performed and execution stops with a corresponding error message. Non-fatal error conditions do not lead to program termination but just produce a warning message which should clearly indicate the nature of the problem such the the user can reliably assess the correctness of returned/computed quantities.

Several CAL routines also issue diagnostic messages which provide to the expert user detailed information about the operations being performed. These messages shall be of particular value in the case of unexpected error/warning conditions which need to be resolved. The level of diagnostic messages to be issued by the CAL can be controlled via the environment variable SAS_VERBOSITY (see documentation of package error for details).