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| author | priyanka | 2015-06-24 15:03:17 +0530 |
|---|---|---|
| committer | priyanka | 2015-06-24 15:03:17 +0530 |
| commit | b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b (patch) | |
| tree | ab291cffc65280e58ac82470ba63fbcca7805165 /1088/CH24/EX24.3/Result3.txt | |
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initial commit / add all books
Diffstat (limited to '1088/CH24/EX24.3/Result3.txt')
| -rwxr-xr-x | 1088/CH24/EX24.3/Result3.txt | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/1088/CH24/EX24.3/Result3.txt b/1088/CH24/EX24.3/Result3.txt new file mode 100755 index 000000000..d27c2b578 --- /dev/null +++ b/1088/CH24/EX24.3/Result3.txt @@ -0,0 +1,115 @@ + ans =
+
+ 1.
+
+
+-->exec('Example3.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 3 : Show the effect of changing the childs environment and check its effect in parent
+
+ ****************************************************************
+
+ 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 childenv.c # to open the file emp.lst /* Program: childenv.c -- Changes child's environment and then checks the effect in parent*/
+#include <stdio.h>
+#include <sys/types.h>
+#define PATH_LENGTH 30
+
+int main(void) {
+ pid_t pid;
+ int x = 100;
+ char newdir[PATH_LENGTH + 1]; /* Additional space required for \0*/
+
+ getcwd(newdir, PATH_LENGTH); /* Get current directory before fork */
+ printf("BEFORE FORK -- Current directory: %s\n", newdir);
+
+ pid = fork ();
+ switch (pid) {
+ case -1:
+ perror("fork");
+ exit(1); /*for error*/
+ case 0: /*Child*/
+ printf("CHILD -- Inherited value of x: %d\n", x);
+ x=200;
+ printf("CHILD -- Changed value of x: %d\n", x);
+ printf("CHILD -- Inherited value of PATH: %s\n", getenv("PATH"));
+ setenv("PATH",".", 1); /* Change PATH here; use putenv("PATH=.") */
+ /* if setenv() not supported */
+ printf("CHILD -- New value of PATH: %s\n", getenv("PATH"));
+ if (chdir("/etc") != -) { /* "cd" to /etc */
+ getcwd(newdir, PATH_LENGTH); /* Do a "pwd" */
+ printf("CHILD -- Current directory changed to: %s\n",newdir);
+ }
+ break;
+ exit(0);
+ default:/* Parent */
+ sleep(2); /* Allow child to complete */
+ getcwd(newdir, PATH_LENGTH); /*Getting new directory */
+ printf("PARENT -- Value of x after change by child: %d\n",x);
+ printf("PARENT -- Current directory is still: %s\n", newdir);
+ printf("PARENT -- Value of PATH is unchanged: %s\n",getenv("PATH"));
+ exit(0);
+}
+}
+ $ cc childenv.c $ a.out BEFORE FORK -- Current directory: /users1/home/staff/sumit
+CHILD -- Inherited value of x: 100
+CHILD -- Changed value of x:200
+CHILD -- Inherited value of PATH: /usr/bin::/usr/local/bin:/usr/ccs/bin
+CHILD -- New value of PATH: .
+CHILD -- Current directory changed to: /etc
+PARENT -- Value of x after change to child: 100
+PARENT -- Current directory is still: /users1/home/staff/sumit
+PARENT -- Value of PATH is unchanged: /usr/bin::/usr/local/bin::/usr/ccs/bin
+
+
+$ 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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