Why vector use at function can't caught exception in SC?

[Allen yang]

Nowadays, I use at function to access vector and it out of range. However, it didn't pause and the program shutdown only.

#include <systemc>

int sc_main(int args, char* argv[])
{
    std::vector<int> vec = {1, 2, 3};

    int num1 = vec.at(1);
    int num2 = vec.at(10); 

    return 0;
  }

Here's the result:

root@xxx:/home#
        SystemC 2.3.3-Accellera --- Jan 25 2024 15:41:45
        Copyright (c) 1996-2018 by all Contributors,
        ALL RIGHTS RESERVED
Error: (E549) uncaught exception: vector::_M_range_check: __n (which is 10) >= this->size() (which is 3)
In file: ../../../src/sysc/kernel/sc_except.cpp:101
root@xxx:/home#

 

I expected it will be like below, and the program will be crash and output coredump file.

terminate called after throwing an instance of 'std::out_of_range'
  what():  vector::_M_range_check: __n (which is 10) >= this->size() (which is 3)

 

 

[AmeyaVS]

Hello @Allen yang,

It is because sc_main is called within a context of a try catch block.

See this:

https://github.com/accellera-official/systemc/blob/bec101067d808f93bf215031dff6fa9ab7035995/src/sysc/kernel/sc_main_main.cpp#L66-L108\

Captured the snippet from the implementation and reproduced below.

try
    {
        pln();

        // Perform initialization here
        sc_in_action = true;

        // copy array of pointers to keep allocated pointers for later release
        std::vector<char*> argv_call = argv_copy;
        status = sc_main( argc, &argv_call[0] );

        // Perform cleanup here
        sc_in_action = false;
    }
    catch( const sc_report& x )
    {
        sc_report_handler::get_handler()
            ( x, sc_report_handler::get_catch_actions() );
    }
    catch( ... )
    {
        // translate other escaping exceptions
        sc_report*  err_p = sc_handle_exception();
        if( err_p )
            sc_report_handler::get_handler()
                ( *err_p, sc_report_handler::get_catch_actions() );
        delete err_p;
    }

You can see there is a broader catch( ... ) statement which is causing the exception to be handled instead of being thrown.

You can possibly try writing you own main function but will need to take care of additional SystemC kernel initialization sequences.

Hope this helps.

Regards,

Ameya Vikram Singh

[Allen yang]

Hi @AmeyaVS,

Thank you for your help. Do you mean that I should rewrite `sc_main_main.cpp` by myself fixing `catch(...) ...` code ? Can I just use code below?

    catch( ... )
    {
        // don't translate other escaping exceptions
    }

 

[AmeyaVS]

Hello @Allen yang,

You could try removing the catch all block itself, so that the exceptions is thrown from the sc_main method.

Regards,

Ameya Vikram Singh

[Allen yang]

I have try your advice and it works. Thanks!

 

[Allen yang]

Hi @AmeyaVS,

When I try `vector::at` in `SC_METHOD` or `SC_(C)THREAD`, the stack can't be show. I try to rewrite `sc_except.cpp::sc_handle_exception`, it didn't work. Can you help me figure out this?

Regards,

Allen

[AmeyaVS]

2 hours ago, Allen yang said:

I try to rewrite `sc_except.cpp::sc_handle_exception`, it didn't work. Can you help me figure out this?

Hello @Allen yang,

It is possible to get a stack trace, but then again what is your use-case?

Regards,

Ameya Vikram Singh

[Allen yang]

12 hours ago, AmeyaVS said:

Hello @Allen yang,

It is possible to get a stack trace, but then again what is your use-case?

Regards,

Ameya Vikram Singh

My use-case is in `SC_METHOD` or `SC_(C)THREAD` if exception caught I can see the ori stack trace with c++ not rethrow or caught by `sc_report`.

The stack trace isn't my exception. I don't want to use `catch throw` to get stack trace which I really need.