c++/10606: uncaught_exception() returns false too early

[sebor@roguewave.com]

>Number:         10606
>Category:       c++
>Synopsis:       uncaught_exception() returns false too early
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri May 02 21:26:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     sebor@roguewave.com
>Release:        3.2
>Organization:
>Environment:

>Description:
The program below shows that the gcc implementation of uncaught_exception() violates 15.5.3, p1. Specifically, the function is required to return true "until completing the initialization of the exception-declaration in the matching handler" which the gcc impletation fails to do (the output line marked <<<).

Martin
>How-To-Repeat:
$ cat t.cpp; g++ t.cpp && ./a.out 
#include <stdio.h>
#include <exception>

int main ()
{
#define SHOW(fun)   \
    printf ("%s(%d): %s: uncaught_exception() = %d\n", \
            __FILE__, __LINE__, fun, std::uncaught_exception ())

    struct S {
        S () { SHOW ("S::S()"); }
        S (const S &s) { SHOW ("S::S(const S&)"); }
        ~S () { SHOW ("S::~S()"); }
    };
    try {
        S s;

        throw s;
    }
    catch (S s) {
        SHOW ("catch");
    }
}
t.cpp(11): S::S(): uncaught_exception() = 0
t.cpp(12): S::S(const S&): uncaught_exception() = 0
t.cpp(13): S::~S(): uncaught_exception() = 1
t.cpp(12): S::S(const S&): uncaught_exception() = 0 <<<
t.cpp(21): catch: uncaught_exception() = 0
t.cpp(13): S::~S(): uncaught_exception() = 0
t.cpp(13): S::~S(): uncaught_exception() = 0
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: