This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 117a. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2025-04-13

98. Branching into try block

Section: Clause 14 [except] Status: TC1 Submitter: Jack Rouse Date: 23 Feb 1999

At the top of clause 15, in paragraph 2, it says:

A goto, break, return, or continue statement can be used to transfer control out of a try block or handler, but not into one.

What about switch statements?

 switch ( f() ) { case 1: try { g(); case 2: h(); } catch (...) { // handler } break; }

Daveed Vandevoorde:

Consider:

 void f() { try { label: ; } catch(...) { goto label; } }

Now the phrase "try block" (without a hyphen) is used in paragraph 1 in a way that causes me to think that it is not intended to include the corresponding handlers. On the other hand, the grammar entity "try-block" (with hyphen) does include the handlers. So is the intent to prohibit the above or not?

Proposed resolution (10/00:

Change text in Clause 14 [except] paragraph 2 from:

A goto, break, return, or continue statement can be used to transfer control out of a try block or handler, but not into one.

to:

A goto or switch statement shall not be used to transfer control into a try block or into a handler.
[ Example:
void f() {
goto l1; // Ill-formed
goto l2; // Ill-formed
try {
    goto l1; // OK
    goto l2; // Ill-formed
    l1: ;
} catch (...) {
    l2: ;
    goto l1; // Ill-formed
    goto l2; // OK
}
}
—end example ]
A goto, break, return, or continue statement can be used to transfer control out of a try block or handler.

(See also issue 246.)