没有这一步内核不会知道应该将信号发送给哪个进程fcntl(STDIN_FILENO, F_SETOWN, getpid());//获得文件的状态标志oflags =fcntl(STDIN_FILENO, F_GETFL);//启动异步通知机制fcntl(STDIN_FILENO, F_SETFL, oflags |FASYNC);while(1);
而在Linux系统中,实现文件锁的函数之一就是fcntl()函数。fcntl()函数是Unix/Linux系统中的文件控制函数,它可以对文件描述符进行各种控制操作,其中包括文件锁。 在Linux系统中,fcntl()函数的原型是: ``` intfcntl(int fd, int cmd, ... /* str 文件锁...
flags &= ~(FASYNC); if (set) { if (fcntl(fd, F_SETOWN, getpid()) == -1) panic("Could not set up async IO"); } if (fcntl(fd, F_SETFL, flags) == -1) panic("Could not set up async IO"); 👍1 Activity Sign up for free to join this conversation on GitHub. Already ha...
F_GETFL 取得文件描述词状态旗标,此旗标为open()的参数flags。 F_SETFL 设置文件描述词状态旗标,参数arg为新旗标,但只允许O_APPEND、O_NONBLOCK和O_ASYNC位的改变,其他位的改变将不受影响。 F_GETLK 取得文件锁定的状态。 F_SETLK 设置文件锁定的状态。此时flcok 结构的l_type 值必须是F_RDLCK、F_WRLCK或...
在网络编程中,fcntl常用来设置或清除文件描述符(如socket描述符)的某些状态标志。例如,设置文件描述符为非阻塞模式(O_NONBLOCK)或注册异步IO通知(FASYNC)。 2. 安装netcat工具-【我们主要用它来发送消息,当做一个简单的客户端】 netcat是一个功能强大的网络工具,它可以用于调试和探测网络服务。除了简单的TCP连接,它...
fcntl(sg_fd, F_SETFL, oflags | FASYNC)www.tldp.org/HOWTO/SCSI-Generic-HOWTO/fcntl.html ...
fcntl函数能够改变已经打开文件的属性。 ? fcntl函数的的功能其实很复杂,它的功能取决于cmd这个参数。...在获取(修改)已打开文件状态标志的时候,cmd这个参数取F_GETFL或F_SETFL #include #includefcntl.h> #include...int flag = fcntl(fd...
There are several types of flags associated with each open object. Flags for an object are represented by symbols defined in the <fcntl.h> header file. The followingfile statusflags can be associated with an object: FASYNCTheSIGIOsignal is sent to the process when it is possible to do I/...
FD_DIRECTORY The specified file descriptor refers to a directory. F_SETFL Set the file status flags for the specified file descriptor. The argument is the new set of flags, as a variable of type int. These flags are as specified for the oflag argument to open(), along with the addi...
=item C<FD_CLOEXEC> During a successful C<exec> call, the file descriptor will be closed automatically. =back =item C<F_GETFL> Return (as a number) the set of file description status flags (O_*) as set by C<open> and C<fcntl>. To determine the file access mode, perform a bitwi...