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https://www.tsingfun.com/it/cpp/2163.html 

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...
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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,...
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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 ...
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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...
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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...
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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...
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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...
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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...
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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...
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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) { ...