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Diffstat (limited to '1088/CH24/EX24.16/Result16.txt')
| -rwxr-xr-x | 1088/CH24/EX24.16/Result16.txt | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/1088/CH24/EX24.16/Result16.txt b/1088/CH24/EX24.16/Result16.txt new file mode 100755 index 000000000..2225a189d --- /dev/null +++ b/1088/CH24/EX24.16/Result16.txt @@ -0,0 +1,110 @@ + ans =
+
+ 1.
+
+-->exec('Example16.sci')
+
+-->clear
+
+-->flag=1
+ flag =
+
+ 1.
+
+-->mode(-1)
+Current date is 23-Jun-2013
+
+Welcome to the Textbook Companionship Project 2013
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ Book Title : UNIX CONCEPTS AND APPLICATIONS
+
+ Book Edition : 4
+
+ Book Author : Sumitabha Das
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ Code Author : Pranav Bhat T
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ Chapter Number : 24
+
+ Chapter Title : Systems programming II- Files
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+Example 16 : Show the method of using fork and exec to run a user-defined
+ program and kill it in 5 seconds if not completed
+
+ ****************************************************************
+
+ Answer :
+
+ INSTRUCTIONS :
+
+ 1.These programs are part of systems programming PURELY in Unix and the commands have NO EQUIVALENT IN SCILAB
+
+ 2.However the .c files which are displayed here are also made into a seperate file.If you are a unix user then try compiling and
+ running the programme with gcc or cc compiler
+
+ 3.The outputs displayed here are just MOCK OUTPUTS which are DISPLAYED IN THE TEXTBOOK
+
+ 4.The inconvenience is regretted.
+.............Press [ENTER] to continue..... UNIX SHELL SIMULATOR(DEMO VERSION WITH PRELOADED COMMANDS)
+
+
+
+
+$ cat killprocess.c # to open the file emp.lst /* Program: killprocess.c -- Uses fork and exec to run a user-defined program and kills it if it doesnt complete in 5 seconds */
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+
+pid_t pid;
+int main(int argc, char **argv) {
+ int i,status;
+ void death_handler(int signo); /* A common signal handler this time */
+
+ signal(SIGCHLD, death_handler); /* death_handler is invoked when a */
+ signal(SIGALRM, death_handler); /* child dies or an alarm is recieved */
+
+ switch (pid = fork()) {
+ case -1: printf("Fork error\n");
+ case 0: execvp(argv[1],&argv[1]); /* Execute command */
+ perror("exec");
+ break;
+ default: alarm(5); /* Will send SIGALRM after 5 seconds */
+ pause(); /* Will return when SIGCHILD signal is received */
+ printf("Parent dies\n");
+ }
+ exit(0);
+ }
+
+ void death_handler(int signo) { /* This common handler pics up the */
+ int status; /* exit status for normal termination */
+ signal(signo, death_handler); /* but sends the SIGTERM signal if */
+ switch(signo) { /* command doesnt complete in 5 seconds */
+ case SIGCHLD: waitpid(-1, &status, 0); /* Same as wait(&status); */
+ printf("Child dies; exit status: %d\n",WEXITSTATUS(status));
+ break;
+ case SIGALRM: if (kill(pid, SIGTERM) == 0)
+ fprintf(stderr, "5 seconds over,child killed\n");
+ }
+}
+ $ cc killprocess.c $ a.out date Sat Jun 20 22:29:27 IST 2013
+Child dies: exit status: 0
+Parent dies
+$ a.out find /home -name a.out -print /home /sumit/personal/project8/a.out
+/home/sumit/personal/books_code/glass_ables/12/a.out
+/home/sumit/personal/books_code/stevens_c/ch08/a.out ..after 5 second time interval ...
+5 seconds over, child killed
+Parent dies
+
+
+
+$ exit #To exit the current simulation terminal and return to Scilab console
+
+........# (hit [ENTER] for result)
+
+ BACK TO SCILAB CONSOLE...
+Loading initial environment
+-->diary(0)
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