Ada Programming/Pragmas/No Return

Pragmas No_Return __TOC__ pragma No_Return (local_name); Description No Return is a representation pragma for procedures, which states that a procedure will never return normally; that is, it will raise an exception, loop endlessly, or terminate the program (e.g. by means of an imported function like C’s exit or by triggering a hardware reset). On the call site, this enables detection of dead code and suppression of warnings about missing return statements or missing assignment to variables. The compiler ensures that a non-returning procedure will indeed not return by raising Program_Error if it would otherwise. Example procedure P ( … ); No_Return (P); procedure Q (x: out … ) is begin if Cond then P ( … ); Some_Thing_Else; This is dead code--and due to No_Return probably a compiler warning! else x := … ; end if; No warning about a missing assignment to x here end Q; Portability The pragma No_Return is standard in the language since Ada 2005. Some compilers (e.g. GNAT and AdaMagic) already recognised No_Return as implementation defined pragma before.AI95-00329 in Appendix: From: Tucker Taft, Sent: Tuesday, March 4, 2003 11:13 AM See also Wikibook Ada Programming Ada Programming/Pragmas Ada Programming/Subprograms Ada Reference Manual 6 5 1 Pragma No_Return References No_Return No_Return