Sun S3L 3.0 Programming and Reference Guide

Levels of Error Checking

The Sun S3L safety mechanism has four selectable levels: 0, 2, 5, and 9. These levels are defined in Table 6-1.

At levels 2, 5, and 9, some safety mechanism error messages are displayed at the terminal when you run the program; other information appears in the backtrace when you use a debugger such as Prism.

Table 6-1 S3L Safety Mechanism Levels


0	Turns off the safety mechanism. Explicit synchronization and error checking are not performed. This level is appropriate for production runs of code that has already been thoroughly tested.
2	Detects potential race conditions in multithreaded S3L operations on parallel arrays. To avoid race conditions, an S3L function locks all parallel array handles in its argument list before proceeding. This safety level causes warning messages to be generated if more than one S3L function attempts to use the same parallel array at the same time.
5	Detects and reports all level-2 errors. In addition, level 5 performs explicit synchronization before and after each call and locates each error with respect to the synchronization points. This safety level is appropriate during program development or during runs for which a small performance penalty can be tolerated.
9	Checks for and reports all level 2 and level 5 errors, as well as errors generated by lower levels of code that were called from within S3L. Performs explicit synchronization in these lower levels of code and locates each error with respect to the synchronization points. This level performs all implemented error checking and exacts a very high performance price. It is appropriate for detailed debugging when a problem occurs.