Run A Process
/* * Simple program to demonstrate the fork/exec/run sequence for creating * processes in Unix. */ #include <iostream> #include <string> using namespace std; #include <unistd.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/wait.h> int main() { /* Ask for a program to run. This is just the file name of an executable. */ cout << "What shall I run? "; string cmd; getline(cin, cmd); /* Request a single parameter. */ cout << "Would you like a parameter for that? (return for none) "; string parm; getline(cin, parm); /* Create a child process and try to run the program in it. */ if(fork() == 0) { if(parm.length() > 0) execl(cmd.c_str(), cmd.c_str(), parm.c_str(), NULL); else execl(cmd.c_str(), cmd.c_str(), NULL); cout << "Sorry, the exec failed." << endl; exit(1); } /* See what was the cause of the child processes' demise. */ int status; wait(&status); if(WIFEXITED(status)) cout << "Exited." << endl; else if(WIFSIGNALED(status)) cout << "Killed." << endl; else cout << "Mysteriously vanished." << endl; } /* * Note: This program really should check the return values for fork() and for * exec() to make sure they succeeded, and print an error message if not. * Failure is indicated by a negative return value. It would also help to use * errno and strerror() to print a descriptive error message in place of the * existing exec() failure message, or for the new messages. */