The Sun S3L Safety Mechanism

The Sun S3L safety mechanism offers two basic features: It synchronizes the parallel processes so that you can pinpoint the area of code that generated an error. It also performs error checking and reports errors at a user-selectable level of detail.

Synchronization

When a Sun S3L application executes on multiple processes, the processes are generally running asynchronously with respect to one another. The Sun S3L safety mechanism provides an interface for explicitly synchronizing the processes to each Sun S3L call made by your code. It traps and reports errors, indicating when the errors occurred relative to the synchronization points.

Error Checking and Reporting

The safety mechanism can perform error checking and generate run-time error information at multiple levels of detail. You can turn safety checking on at any level during all or part of a program. One level checks for errors in the usage and arguments of the Sun S3L calls in your program; a more detailed level also checks for errors generated by internal Sun S3L routines. Examples of errors found and reported by the safety mechanism include the following:

• A supplied or returned data element that should be numerical is not. For example, it is identified as a Not a Number (NaN), or as infinity. NaNs are defined in the IEEE Standard for Binary Floating-Point Arithmetic.

• The code generates a division by 0 (for example, because of bad data, a user error, or an internal software problem).

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  Note -

  For performance reasons, Sun S3L conducts most of its argument checking and error handling independently on each process. Consequently, when the safety mechanism is enabled and an error is detected, different processes may return different error values.

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