c - fork() function will never return 0 -

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i trying run fork function in c in child section of code, trying execute command using exacvp, before execution trying printf function never executes. ran in debug , have noticed pid never assigned 0. did try simple fork example on separate project , worked smoothly. have idea why child section never executes?

int startprocesses(int background) { int = 0;  while(*(linearray+i) != null) {     int pid;     int status;     char *processname;      pid = fork();      if (pid == 0) {          printf("i child");         // child process         processname = strtok(linearray[i], " ");         execvp(processname, linearray[i]);         i++;         continue;      } else if (!background) {          // parent process         waitpid(pid, &status, 0);         i++;         if(wexitstatus(status)) {             printf(cannot_run_error);             return 1;         }     } else {         i++;         continue;     } } return 0;

}

stdio files flushed on program's exit, execvp directly replaces process image, bypassing flush-at-exit mechanism , leaving i child message in memory never sent screen. add explicit fflush(stdout) before execvp, or end string \n automatically flushed when running on tty.

note execvp never exits, , if does, because has failed execute new process. @ point, only thing child can report error , call _exit(127) (or similar exit status). if child continues, incorrectly configured command name cause execute rest of parent's loop in parallel parent. process continue other descendants, creating fork bomb can grind system halt.


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