Linux File Description Descriptor set to non-clogging method

PassFcntlSet File Description Descriptor PropertiesFcntl is the use of F_SETFL,F_GETFL, set the file of flags, clogging is set to non-clogging, non-clogging is set to plug (this can be encapsulated as a basic function in server development)1. Get the flags of the file, which is the second parameter of the Open function:

    Flags = FCNTL (fd,f_getfl,0);

2, set the file flags:

     Fcntl (Fd,f_setfl,flags);

3. Add a flags for the file. For example, the file is blocked and you want to set it to non-clogging:

      Flags = FCNTL (fd,f_getfl,0);      Flags |= O_nonblock;      Fcntl (Fd,f_setfl,flags);

Or one step the way:

     Fcntl (Socket,f_setfl,fcntl (SOCKET,F_GETFL) | O_nonblock);

4, cancel a file of a flags, for example, the file is non-clogging, want to set up a blockage: 

    Flags = FCNTL (fd,f_getfl,0);    Flags &= ~o_nonblock;    Fcntl (Fd,f_setfl,flags);

PassSocket APIcreate a non-cloggingSocket

</pre><pre name= "code" class= "CPP" > #include <sys/types.h> #include <sys/socket.h>int socket ( int domain,int type,int protocal);

TypeSpecify the type of service, the type of service is mainlySock_streamServices,Sock_dgreamservice, it is worth noting that theLinuxKernel version number2.6.17up,typeParticipants can accept the following two logos at the same time as these services:Sock_nonblock,sock_cloexec,each of them represents the newly createdsockset to non-clogging, as well as inForkcall when creating a child process is closed in a child processsocket.However, the previous version number is not supported.

1. Creating blockagesSocket

    int fd_sock = socket (af_inet,sock_stream,0);

2. create non-clogging sockets

    int fd_sock = socket (af_inet,sock_stream| sock_nonblock,0);

The above code indicates that a new socket created is non-clogging

Linux File Description Descriptor set to non-clogging method