sc_fifo.h warnings with gcc -DNDEBUG

[Timur Kelin]

include/sysc/communication/sc_fifo.h:269:10: warning: unused variable ‘write_success’ [-Wunused-variable]
     bool write_success = sc_fifo<T>::nb_write(val_);
          
include/sysc/communication/sc_fifo.h:226:10: warning: unused variable ‘read_success’ [-Wunused-variable]
     bool read_success = sc_fifo<T>::nb_read(val_);

 

sc_fifo.h:

    bool write_success = sc_fifo<T>::nb_write(val_);
    sc_assert( write_success );

 

sc_report.h

#if defined(NDEBUG) && !defined(SC_ENABLE_ASSERTIONS) // disable assertions

#define sc_assert(expr) \
 ((void) 0)
 
 ....

i.e. expr is not addressed  when assertions are disabled

 

This is resolved with

#if defined(NDEBUG) && !defined(SC_ENABLE_ASSERTIONS) // disable assertions

#define sc_assert(expr) \
 ((void)(expr))
  
....

 

[Paul Floyd]

sc_assert does the same as the C std lib assert.

 

You probably don't want to paste `expr` in the macro in case it has side effects (not that you should be doing that).

[Timur Kelin]

True. 

It means that the updates should be made to sc_fifo.h:

template <class T>
inline
void
sc_fifo<T>::read( T& val_ )
{
    while( num_available() == 0 ) {
	sc_core::wait( m_data_written_event );
    }
    bool read_success = sc_fifo<T>::nb_read(val_);

    if( !read_success ) {
       sc_assert( read_success );
    }
}

 

[maehne]

Thanks @Timur Kelin for reporting this issue! I have forwarded it to the SystemC LWG to investigate how to fix it best in the proof-of-concept implementation of SystemC.