4.3  Structured Blocks

This section specifies the concept of a structured block. A structured block:

• may contain infinite loops where the point of exit is never reached;

• may halt due to an IEEE exception;

  ∙ may contain calls to exit(), _Exit(), quick_exit(), abort() or functions with a _Noreturn specifier (in C) or a noreturn attribute (in C/C++); ∙ may be an expression statement, iteration statement, selection statement, or try block, provided that the corresponding compound statement obtained by enclosing it in { and } would be a structured block; and
  ∙ may contain STOP or ERROR STOP statements.

Restrictions

• Entry to a structured block must not be the result of a branch.

• The point of exit cannot be a branch out of the structured block.

  ∙ The point of entry to a structured block must not be a call to setjmp. ∙ longjmp must not violate the entry/exit criteria of structured blocks.
  ∙ throw, co_await, co_yield and co_return must not violate the entry/exit criteria of structured blocks.