Condition prefixes

You can use a condition prefix to specify whether some conditions are enabled or disabled. If a condition is enabled, the compiler generates any extra code needed in order to detect the condition. If a condition is disabled, the compiler generates no extra code to detect it.

Disabling a condition is equivalent to asserting that the condition cannot occur; if it does, your program is in error. For instance, if the SUBSCRIPTRANGE condition is enabled, the compiler generates extra code to ensure that any array index is within the bounds of its array. If the SUBSCRIPTRANGE condition is disabled, the extra code is not generated and using an invalid array index leads to unpredictable results.

If a condition is detected by hardware, disabling the condition has no effect.

You can specify a condition prefix only for eligible conditions.

condition

Some conditions are always enabled, and cannot be disabled. Some are enabled unless you disable them, and some are disabled unless you enable them. The conditions are listed in Conditions.

statement

Condition prefixes are not valid for DECLARE, DEFAULT, FORMAT, OTHERWISE, END, ELSE, ENTRY, and %statements. For information about the scope of condition prefixes, see Scope of the condition prefix.

  (size):  L1:  X=(I**N) / (M+L);

To enable conditions, specify the condition prefix with the condition name. To disable conditions, specify the condition prefix with the condition name, preceded by NO without intervening blanks.

Types and status of conditions are shown in Table 1.

For information about the performance effects of enabling and disabling conditions, refer to the Programming Guide.