win7 64位 下，进程可申请的堆空间

void test(){
    char * c = NULL;
    // input bad_alloc
    //unsigned int i = (unsigned int)pow(2,31);

    // ok
    unsigned int i = (unsigned int)pow(2,30);
    try{
        c = new char[i];
    }catch(bad_alloc& e){
        cout << e.what() << endl;
        //cout << s << endl;
    }
    if( c != NULL)
        delete []c;
}