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How much is the overhead of smart pointers compared to normal pointers in C++?
...ude <thread>
uint32_t n = 100000000;
void t_m(void){
auto a = (char*) malloc(n*sizeof(char));
for(uint32_t i=0; i<n; i++) a[i] = 'A';
}
void t_u(void){
auto a = std::unique_ptr<char[]>(new char[n]);
for(uint32_t i=0; i<n; i++) a[i] = 'A';
}
void t_u2(void){
a...
Remove specific characters from a string in Python
I'm trying to remove specific characters from a string using Python. This is the code I'm using right now. Unfortunately it appears to do nothing to the string.
...
See all breakpoints in Visual Studio 2010+
...
In Visual Studio 2017, Ctrl+D duplicates the current selection and Ctrl+B adds a new breakpoint at the current line. Ctrl+F9 does nothing.
– Malcolm
May 7 '19 at 16:16
...
What's the difference between a temp table and table variable in SQL Server?
...-unique indexes too.
Table variables don't participate in transactions and SELECTs are implicitly with NOLOCK. The transaction behaviour can be very helpful, for instance if you want to ROLLBACK midway through a procedure then table variables populated during that transaction will still be populated...
How to allocate aligned memory only using the standard library?
...
Original answer
{
void *mem = malloc(1024+16);
void *ptr = ((char *)mem+16) & ~ 0x0F;
memset_16aligned(ptr, 0, 1024);
free(mem);
}
Fixed answer
{
void *mem = malloc(1024+15);
void *ptr = ((uintptr_t)mem+15) & ~ (uintptr_t)0x0F;
memset_16aligned(ptr, 0, 10...
How is std::function implemented?
... // function pointer types for the type-erasure behaviors
// all these char* parameters are actually casted from some functor type
typedef R (*invoke_fn_t)(char*, Args&&...);
typedef void (*construct_fn_t)(char*, char*);
typedef void (*destroy_fn_t)(char*);
// type-aware...
What is the optimal length for an email address in a database?
...
The maximum length of an email address is 254 characters.
Every email address is composed of two parts. The local part that comes before the '@' sign, and the domain part that follows it. In "user@example.com", the local part is "user", and the domain part is "example.c...
libevent+protobuf轻松搭建tcpserver - C/C++ - 清泛网 - 专注C/C++及内核技术
...:socket(),connect()，返回连接的sockfd
int create_io_channel(const char *ipaddr, int port);
2. 搭建TCP Server
下面以伪代码方式给出，错误处理省略
int main(int argc, char *argv[])
{
// 初始化
…
// event初始化
event_init();
init_server(por...
How to printf uint64_t? Fails with: “spurious trailing ‘%’ in format”
... I wonder if there are progress towards a locale independent and/or locale selectable version of std::to_string(). The cppreference page still link only to std::to_chars(), which is not really what people need. I wonder if fmt and/or c++20 deal with it or not yet.
– ceztko
...
What is The Rule of Three?
...pointers.
The person class might have looked like this:
class person
{
char* name;
int age;
public:
// the constructor acquires a resource:
// in this case, dynamic memory obtained via new[]
person(const char* the_name, int the_age)
{
name = new char[strlen(the_name...