To: J3                                                 09-238r1
From: John Reid
Subject: Inter-procedural transfers
Date: 2009 August 11
References: 09-238, 09-007r2

In 09-238, Nick Maclaren points out that if a C++ procedure is called
(directly or indirectly) from Fortran, it might bypass the return
mechanism of an executing Fortran procedure by using throw/catch.
He suggested adding a note to discourage this. HPC prefers to add
the general rule to normative text and mention exception handling in
a note.


EDITS

[438:25-439:1] In 15.5.1 Definition and reference of interoperable
procedures, para 5, replace the second sentence "If a procedure ..." by
"A procedure that is defined by means other than Fortran and is invoked
during the execution of a Fortran procedure shall not cause a transfer
of control to an executing Fortran procedure instance other than by
returning."

[439:2+] In 15.5.1 Definition and reference of interoperable procedures,
after para 5, add
"NOTE 15.23a
Examples of code that might cause a transfer of control that bypasses
the normal return mechanism of a Fortran procedure are setjmp/longjmp
in C and exception handling in other languages. No such behavior is
permitted by this part of ISO/IEC 1539."