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select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
...过程如下所示：
（1）使用copy_from_user从用户空间拷贝fd_set到内核空间
（2）注册回调函数__pollwait
（3）遍历所有fd，调用其对应的poll方法（对于socket，这个poll方法是sock_poll，sock_poll根据情况会调用到tcp_poll,udp_poll或者datagram_p...
WSAAsyncSelect模型 - C/C++ - 清泛网 - 专注C/C++及内核技术
... IEvent //指定哪些通知码需要发送
//FD_READ可以读套接字
//FD_WRITE 可以写套接字
//FD_ACCEPT 监听套接字有连接接入
//FD_CONNET 如果套接字连接对方主机，...
How can I pipe stderr, and not stdout?
...
You could use /dev/stdout et al, or use /dev/fd/N. They will be marginally less efficient unless the shell treats them as special cases; the pure numeric notation doesn't involve accessing files by name, but using the devices does mean a file name lookup. Whether you ...
How to open, read, and write from serial port in C?
...lt;termios.h>
#include <unistd.h>
int
set_interface_attribs (int fd, int speed, int parity)
{
struct termios tty;
if (tcgetattr (fd, &tty) != 0)
{
error_message ("error %d from tcgetattr", errno);
return -1;
}
cfs...
What happens to an open file handle on Linux if the pointed file gets moved or deleted
...1 is returned, and errno is set
* appropriately.
*/
int check_fd_fine(int fd) {
struct stat _stat;
int ret = -1;
if(!fcntl(fd, F_GETFL)) {
if(!fstat(fd, &_stat)) {
if(_stat.st_nlink >= 1)
ret = 0;
else
pr...
How to store standard error in a variable
...ch was saved in file descriptor 3. Note that stderr still refers to where FD 1 pointed before: To the output capturing $(..)
3>&- then closes the file descriptor 3 as it is no more needed, such that command does not suddenly has some unknown open file descriptor showing up. Note that the o...
libevent+protobuf轻松搭建tcpserver - C/C++ - 清泛网 - 专注C/C++及内核技术
libevent+protobuf轻松搭建tcpserver1. 基础代码 设置某fd为O_NONBLOCK模式 int set_non_block(int fd); server端socket流程:socket(),setsoc...1. 基础代码
// 设置某fd为O_NONBLOCK模式
int set_non_block(int fd);
// server端socket流程:socket(),setsockopt(),bi...
Caveats of select/poll vs. epoll reactors in Twisted
...e highest numbered file descriptor you pass it. If you select on a single fd, 100, then that's roughly twice as expensive as selecting on a single fd, 50. Adding more fds below the highest isn't quite free, so it's a little more complicated than this in practice, but this is a good first approxima...
How to read a single character from the user?
...tty, sys
def __call__(self):
import sys, tty, termios
fd = sys.stdin.fileno()
old_settings = termios.tcgetattr(fd)
try:
tty.setraw(sys.stdin.fileno())
ch = sys.stdin.read(1)
finally:
termios.tcsetattr(fd, termios.TCSADR...
Linux C/C++进程单实例互斥代码分享 - C/C++ - 清泛网 - 专注C/C++及内核技术
...h>
#define kPidFileName "app.pid"
bool enter_app_singleton() {
int fd = open(kPidFileName, O_RDWR | O_TRUNC);
if (fd == -1) {
//对应的锁文件当前不存在，试图创建该锁文件
fd = creat(kPidFileName, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
if (fd > 0) {
...