Ada Reference Manual (Ada 2022) — Legal Information

11.3 Raise Statements and Raise Expressions

A raise_statement raises an exception.

Syntax

2/2

raise_statement ::= raise;
| raise exception_name [with string_expression];

2.1/4

raise_expression ::= raise exception_name [with string_simple_expression]

2.2/4

If a raise_expression appears within the expression of one of the following contexts, the raise_expression shall appear within a pair of parentheses within the expression:

2.3/4

object_declaration;

2.4/4

modular_type_definition;

2.5/4

floating_point_definition;

2.6/4

ordinary_fixed_point_definition;

2.7/4

decimal_fixed_point_definition;

Legality Rules

3/4

The exception_name, if any, of a raise_statement or raise_expression shall denote an exception. A raise_statement with no exception_name (that is, a re-raise statement) shall be within a handler, but not within a body enclosed by that handler.

Name Resolution Rules

3.1/4

The string_expression or string_simple_expression, if any, of a raise_statement or raise_expression is expected to be of type String.

3.2/4

The expected type for a raise_expression shall be any single type.

Dynamic Semantics

4/4

To raise an exception is to raise a new occurrence of that exception, as explained in 11.4. For the execution of a raise_statement with an exception_name, the named exception is raised. Similarly, for the evaluation of a raise_expression, the named exception is raised. In both of these cases, if a string_expression or string_simple_expression is present, the expression is evaluated and its value is associated with the exception occurrence. For the execution of a re-raise statement, the exception occurrence that caused transfer of control to the innermost enclosing handler is raised again.

4.1/4

NOTE If the evaluation of a string_expression or string_simple_expression raises an exception, that exception is propagated instead of the one denoted by the exception_name of the raise_statement or raise_expression.

Examples

Examples of raise statements:

6/2

raise Ada.IO_Exceptions.Name_Error; -- see A.13
raise Queue_Error with "Buffer Full"; -- see 9.11

raise; -- re-raise the current exception

8/5

-- For an example of a raise expression, see the Streams Subsystem definitions in 13.13.1.

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