Как бы увидеть стек исключения?

int a = 1;
double b = 2.5;

void somefunc() {
                                b = b * b + (a = ((a % 2 == 0) ? a * 2 + 1 : a + 3));
}

int main() {
  somefunc();
  somefunc();
  ...

break main
run
while 1
        s
        bt
        printf "\na = %d, b = %f\n", a, b
end

$ gdb -x 1.gdb ./a.out 

//------------------------------------------------------------------------------
	class debug_info{
		int pos, N, line; char* names[256];
	public:
		Ostream& stream;

		debug_info( Ostream& Astream, const char* args, const char* file, int line );
		~debug_info();
		const char* expr(){ if( pos<N ) return names[pos]; else return 0; }
		void next(){ if( pos < N ) stream.printf( names[pos++] );	else raise( "debug_info()::next() names vector overflow, N=%i", N ); }

#ifndef SWIG
		debug_info& operator , ( bool v ){ next(); stream.printf( "=%s", v?"True":"False" ); return *this; }
		debug_info& operator , ( char v ){ next(); stream.printf( "=%c", v ); return *this; }
		debug_info& operator , ( int  v ){ next(); stream.printf( "=%d",  v ); return *this; }
		debug_info& operator , ( long v ){ next(); stream.printf( "=%ld", v ); return *this; }
		debug_info& operator , ( size_t v ){ next(); stream.printf( "=%ld", v ); return *this; }
		debug_info& operator , ( float v  ){ next(); stream.printf( "=%g", v ); return *this; }
		debug_info& operator , ( double v ){ next(); stream.printf( "=%g", v ); return *this; }
		debug_info& operator , ( const char* v ){ next(); stream.printf( "=%s", v && strlen(v)?v:"\"\"" ); return *this; }
#endif //SWIG
	};

	template< class T > debug_info& operator, ( debug_info& S, T* ptr ){ S.next(); S.stream.printf("=>%0x", ptr ); return S; }
//	template< class T > void write_debug_info( debug_info& S, const T& v ){ S,v; }
#define WOUT( args... ) { ::aiv::debug_info _tmp_debug_info_obj( ::aiv::mystdout, #args, __FILE__, __LINE__ ); _tmp_debug_info_obj,args; }
#define WERR( args... ) { ::aiv::debug_info _tmp_debug_info_obj( ::aiv::mystderr, #args, __FILE__, __LINE__ ); _tmp_debug_info_obj,args; }
#define WSTR( stream, file, line, args... ) { ::aiv::debug_info _tmp_debug_info_obj( stream, #args, file, line ); _tmp_debug_info_obj,args; }
//------------------------------------------------------------------------------

debug_info::debug_info(Ostream& Astream, const char* S, const char* file, int Aline):pos(0),N(0),line(Aline),stream(Astream){
	int i=0, p=0, len = strlen(S), brc=0, brp=0, brf=0;
	do{
		if( S[i]=='(' ) brc++; if( S[i]==')' ) brc--;
		if( S[i]=='[' ) brp++; if( S[i]==']' ) brp--;
		if( S[i]=='{' ) brf++; if( S[i]=='}' ) brf--;
		if( brc || brp || brf ) continue;
		if( S[i]==',' ){ names[N] = new char[ i-p+1 ]; strncpy( names[N], S+p, i-p ); names[N++][i-p]=0; p=i+1; }
		if( N>255 ) raise( "show_ifo::debug_info( \"%s\" ) --- names vector overflow", S );
	} while( ++i < len );
	names[N] = new char[ i-p+1 ]; strncpy( names[N], S+p, i-p ); names[N++][i-p]=0; p=i+1;
	if( file && line ) stream.printf( "#%s %i: ", file, line );
	else if( file ) stream.printf( file );
}
debug_info::~debug_info(){ 
	if(line) stream.printf("\n"); 
	for( int i=0; i<N; i++ ) delete [] names[i]; 
	if( pos != N) raise( "debug_info::~debug_info() --- not all expressions out, pos=%i != N=%i", pos, N );
}

debug_info& operator, (debug_info& S, T obj)