The code creates a new terminal and prints the output of the new terminal to a file for the mode.

Transferred from: http://blog.chinaunix.net/uid-20682147-id-4981769.html

Cat term.c#include<stdio.h> #include <stdbool.h> #include <stdlib.h> #include <string.h># include<sys/prctl.h> #include <unistd.h> #include <utmp.h> #include <signal.h> #include < pty.h> #include <fcntl.h>static void on_signal (int signo) {printf ("[%d] signal:%s \ n", Getpid (), Strsignal ( Signo));}    int main () {int amaster = 0;char name[100];struct Termios termp;     Termios.h (bits/termios.h) struct winsize winp; Term.h (bits/ioctl-types.h) pid_t pid = Forkpty (&amaster, name, &AMP;TERMP, &AMP;WINP), if (PID < 0) {perror ("fork Pty "); exit (1);} else if (0 = = pid) {//child processes that are part of the new terminal//subprocess () are not visible on the terminal of the parent process//The parent process is interrupted or hung out will send Sighupsignal (SIGHUP, on_signal) to the child process;p rintf (" Child:%d \ n ", Getpid ()); int save_fd = DUP (stdout_fileno); int fd = open (" 1.txt ", (O_rdwr | o_creat), 0644);d up2 (Fd,stdout_fileno), while (true) {sleep (1);p rintf ("Sub process printf!!! \ n ");} Exit (0);} else if (PID > 0) {///parent process used before terminal//If interrupt sends sighupprintf to process ("pid:%d/%d\n", Getpid (), PID);p rintf("Name:%s\n", name);p rintf ("Amaster:%d\n", Amaster);p rintf ("Win.row:%d\n", Winp.ws_row);p rintf ("Win.col:%d\n", Winp.ws_col);p rintf ("Win.xpixel:%d\n", Winp.ws_xpixel);p rintf ("Win.ypixel:%d\n", Winp.ws_ypixel); GetChar ();} return 0;}

GCC Term.c-o term-lutil

Tail-f 1.txt
Sub process printf!!!
Sub process printf!!!
Sub process printf!!!
Sub process printf!!!
Sub process printf!!!
Sub process printf!!!
Sub process printf!!!
Sub process printf!!!
Sub process printf!!!
[6598] Signal:hangup
Sub process printf!!!
Sub process printf!!!
Sub process printf!!!

Transferred from: http://blog.csdn.net/wangxvfeng101/article/details/11558697

Method 1: #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <sys           /stat.h> #include <fcntl.h> int main () {fflush (stdout);           Setvbuf (stdout,null,_ionbf,0);           printf ("Test stdout\n"); int save_fd = DUP (Stdout_fileno); Save standard output File Descriptor Note: Be sure to copy a file descriptor with DUP.           Don't use = like a handle under a WINODWS. int fd = open ("Test1.txt", (O_rdwr |           o_creat), 0644); Dup2 (Fd,stdout_fileno);                      Replace the standard output printf ("Test file\n") with our newly opened file descriptor; Return to the standard output again.                      Two ways//Method 1 has the condition of saving standard output//dup2 (Save_fd,stdout_fileno);           Method 2 does not save the standard output case int ttyfd = open ("/dev/tty", (O_RDWR), 0644);           Dup2 (Ttyfd,stdout_fileno);       printf ("Test tty\n");              } Method 2: #include <stdlib.h> #include <stdio.h> #include <unistd.h>           int main () {Fflush (stdout);           Setvbuf (stdout,null,_ionbf,0);           printf ("Test stdout\n"); Freopen ("Test1.txt", "w", stdout);   Note: Do not use this type of code stdout = fopen ("Test1.txt", "w"); So the output is weird.           It is best to replace it with a function such as freopen.           printf ("Test file\n");           Freopen ("/dev/tty", "w", stdout);       printf ("Test tty\n"); }

1. Here we can easily solve the problem of Prinft not output to the screen.
4. There are only two cases.
5. The 1th standard output is redirected.
6. Problem with the 2nd output buffer. Is the first two lines of code in our two cases.
7. Fflush (stdout);  //Refresh the buffer to let it output immediately. Call it after printf and it will be output immediately.
8. Setvbuf (stdout,null,_ionbf,0); //If you have a problem with the last method, use this function. The buffer is directly suppressed. It is directly output.
9. Both of these functions are related to stream buffers.   Specific use and description online there are many.  I'll just say what a stream buffer is, and what it does.  The operating system has set a buffer for reducing IO operations. Wait until the buffer is full and then go to Operation IO. This is to improve efficiency.

The code creates a new terminal and prints the output of the new terminal to a file for the mode.