/* setsid() is allowed only when we are not a process group leader.
* Otherwise our PID serves as PGID of some existing process group
- * and cannot be used as PGID of a new process group. */
+ * and cannot be used as PGID of a new process group.
+ *
+ * Example: setsid() below fails when run alone in interactive shell:
+ * $ setsid PROG
+ * because shell's child (setsid) is put in a new process group.
+ * But doesn't fail if shell is not interactive
+ * (and therefore doesn't create process groups for pipes),
+ * or if setsid is not the first process in the process group:
+ * $ true | setsid PROG
+ * or if setsid is executed in backquotes (`setsid PROG`)...
+ */
if (setsid() < 0) {
pid_t pid = fork_or_rexec(argv);
if (pid != 0) {
* However, the code is larger and upstream
* does not do such trick.
*/
- exit(EXIT_SUCCESS);
+ return EXIT_SUCCESS;
}
/* child */