大约有 118 项符合查询结果（耗时：0.0387秒） [XML]
How to count the number of set bits in a 32-bit integer?
...tset width chops after sign-extension
std::bitset<bitwidth> bs( static_cast<UT>(x) );
return bs.count();
}
See asm from gcc, clang, icc, and MSVC on the Godbolt compiler explorer.
x86-64 gcc -O3 -std=gnu++11 -mpopcnt emits this:
unsigned test_short(short a) { return popcount...
How expensive is RTTI?
...n runtime if you can afford to do
if (typeid(a) == typeid(b)) {
B* ba = static_cast<B*>(&a);
etc;
}
instead of
B* ba = dynamic_cast<B*>(&a);
if (ba) {
etc;
}
The former involves only one comparison of std::type_info; the latter necessarily involves traversing an inhe...
C++实现一款简单完整的聊天室服务器+客户端 - C/C++ - 清泛网 - 专注C/C++及内核技术
...得光标显示。
//
HCURSOR CClientDlg::OnQueryDragIcon()
{
return static_cast<HCURSOR>(m_hIcon);
}
void CClientDlg::OnBnClickedConnect()
{
UpdateData(TRUE);
DWORD ip;
m_ip.GetAddress(ip);
//初始化套接字DLL
WSADATA wsa;
if(WSAStartup(MAKEWORD(2,2),&wsa)!=0){
MessageB...
Polymorphism in C++
..., typename Policy>
void f()
{
Amount x = Policy::thirteen;
x /= static_cast<Amount>(2);
std::cout << traits<Amount>::to_double(x) * 1.1;
}
So, compiler-provided operator overloading for builtin types, Standard conversions, casting / coercion / implicit constructors...
How do I safely pass objects, especially STL objects, to and from a DLL?
...;
original_type get() const
{
original_type result;
result = static_cast<original_type>(*data);
return result;
}
void set_from(const original_type& value)
{
data = reinterpret_cast<safe_type*>(pod_helpers::pod_malloc(sizeof(safe_type))); //note the pod_m...
print call stack in C or C++
... r = dwfl_report_end(dwfl, nullptr, nullptr);
assert(!r);
static_cast<void>(r);
}
// Loop over stack frames.
std::stringstream ss;
{
void* stack[512];
int stack_size = ::backtrace(stack, sizeof stack / sizeof *stack);
for (int i = 0; i ...
What is move semantics?
...remove_reference<T>::type&&
move(T&& t)
{
return static_cast<typename std::remove_reference<T>::type&&>(t);
}
As you can see, move accepts any kind of parameter thanks to the forwarding reference T&&, and it returns an rvalue reference. The std...
tinyxml XML解析库下载（tinyxml2.h 和 tinyxml2.cpp） - 源码下载 - 清泛...
...teSpace( char p ) {
return !IsUTF8Continuation(p) && isspace( static_cast<unsigned char>(p) );
}
inline static bool IsNameStartChar( unsigned char ch ) {
return ( ( ch < 128 ) ? isalpha( ch ) : 1 )
|| ch == ':'
|| ch == '_';
...