Fork handout
- 1. Lab exercise-‐ Using Linux O/S. Instruction: 1. Create p01hw.c c program 2. Save in myc directory 3. Compile by using $gcc p01hw.c (if there is no syntax error, an executable file a.out will be created) 4. $mv a.out p01hw.exe rename 5. Run the executable file by issuing p01hw.exe at the $ prompt p01hw.c #include <stdio.h> main() { printf(“n Hello World nn”); } After successfully create and execute the first program p01hw.c, you are ready to create, compile and execute another c programs. Note: 1. Login into linux/unix by using username/password given by the technician 2. Run gedit/text editor to create your first program (recommended, instead of using vi editor) 3. Open a terminal if you want to issue a Linux command at the $ prompt For example: (study all these commands) $PATH=$PATH:. to include current directory for file searching $echo $PATH to display the content of env. var. PATH $mkdir myc make directory myc $cd myc change to directory myc $vi p01hw.c create p01hw.c program using vi editor In vi: i=insert, <esc> exit to command mode, x=delete a char, :wq or ZZ to save and quit OR $gedit p01hw.c & use gedit to create your program (run at the background) $ls –l to display the content of current directory $ps –ef to display process status / running programs $kill -‐9 nnnn to kill a process with a pid=nnnn Use gedit/text editor to edit a file p02hw.c #include <stdio.h> main() { int i, j=11; for(i=0; i < j; i++) printf(“n%d Hello Worldnn”, i); } p03fork.c #include <stdio.h> #include <unistd.h> main() { int i; i = fork(); printf(“Hello World %d %dn”, i, getpid()); } // getpid() is to display process id (pid) // getppid() is to display parent’s pid p04fork.c #include <stdio.h> #include <unistd.h> main() { printf(“nt Hello Worldnn”); fork(); printf(“nt Peace!nn”); fork(); printf(“nt Bye bye Worldnn”); } Note: Analyze the output! March 2014
- 2. Lab exercise@KPU p05hw.c #include <stdio.h> #include <unistd.h> main() { int i=1; while (i != 0) printf(“n%d Hello %dn”, getpid(),i++); } ü Use CTRL-C to interrupt a running program! ü Based on the pid, use kill to terminate the process. p06fork.c #include <stdio.h> #include <unistd.h> main() { int pid1, pid2, pid3; printf(“nHello Worldnn”); pid1=fork(); pid2=fork(); printf(“nWorld! %d %dnn”, pid1, pid2); pid3=fork(); printf(“nBye bye World %dnn”, getpid()); } p07fork.c #include <stdio.h> #include <unistd.h> main() { int pid1, pid2; printf(“nHello Worldnn”); pid1 = fork(); if (pid1 < 0) printf(“nBye bye Worldnn”); else if (pid1 == 0) printf(“nI’m the childnn”); else { pid2 = fork(); printf(“nI’m the parent/another childnn”, pid2);} } p08fork.c #include <stdio.h> #include <unistd.h> main() { int pid1; printf(“nHello Worldnn”); pid1 = fork(); if (pid1 < 0) printf(“nBye bye Worldnn”); else if (pid1 == 0) { sleep(5); sleep for 5 seconds printf(“nChild processnn”); } else { usleep(2000000); sleep for 2 seconds printf(“nParent processnn”); } } Parent will wake-up first Use gcc to compile a c++ program March 2014
- 3. Lab exercise@KPU p08fork2.c #include <stdio.h> #include <math.h> #include <sys/types.h> #include <unistd.h> int main() { int pid, cpid,ppid,gppid; pid=fork(); if (pid < 0) { printf(" Bye bye World n"); exit(1);} else if (pid == 0) { ppid=getppid(); sleep(5); printf(“Child process %d, parent %dn",cpid=getpid(),ppid);} else { gppid=getppid(); usleep(2000000); printf(" parent process %d grandParent %dn",cpid=getpid(),gppid);} return 0; } Use gcc to compile a c++ program March 2014