c fcntl

Detailed description of fcntl functions for file control and fcntl functions for control Abstract:This article mainly discusses the basic application of the fcntl function for file control. the dup function can copy file descriptors, while the fcntl

Refer to the differences between FCNTL (), LOCKF, flock in LinuxWhat is the difference between these three functions , which are all about locking up a file?First flock and fcntl are system calls, and LOCKF is a library function . LOCKF is actually

I. fcntl Functions Function: manipulate the file descriptor to change the attributes of an opened file. Int fcntl (int fd, int cmd,.../* Arg */); The cmd value can be as follows: Copy file descriptorF_dupfd (long) Set/Get file descriptor

fcntl和select函数彻底搞明白 第一、fcntl函数详细使用        fcntl有强大的功能，它能够复制一个现有的描述符，获得/设置文件描述符标记，获得/设置文件状态标记，获得/设置异步I/O所有权，获得/设置纪录锁。 当多个用户共同使用，操作一个文件的情况，Linux通常采用的方法就是给文件上锁，来避免共享资源产生竞争的状态。 fcntl文件锁有两种类型：建议性锁和强制性锁        

Function Description: Manipulate file characteristics According to the file description.File Control function FcntlHeader file:#include #include Function Prototypes:int fcntl (int fd, int cmd);int fcntl (int fd, int cmd, long arg);int fcntl (int fd,

Function Description: describes the features of a file based on its description.File control functionsFcntl -- file control LibraryStandard C library (libc,-LC) Synopsis# Include ;Int fcntl (int fd, int cmd );Int fcntl (int fd, int cmd, long Arg

embedded Linux system Programming (ii)--File Descriptor control function fcntl Because the fcntl function is too flexible and complex, the fcntl function is listed separately from the file IO , which is easy to read in detail. The function

1. DUP functionThe 1.1 DUP function is used to copy a file descriptor , and the copied file descriptor can be used normally (see Example 1). The DUP function returns one of the smallest available file descriptors in the current File descriptor table

int fcntl (int fd,int cmd,...)The function Fcntl provides a very rich feature. The main dependencies are the various parameters of CMD: Copy an existing file descriptor F_dupfd,f_dupfd_cloexec Gets the flag for the set file descriptor F_

// The lock1.c/* program first creates a file and opens it in a readable way. Then, it adds some content to the file, and then sets two regions in the file, the first region is 10-30 bytes and the shared lock is used. The second region is 40-50