setsid -- Create Session and Specify Process Group ID

SYNOPSIS

 #include <sys/types.h>
 #include <unistd.h>

 pid_t setsid(void);

DESCRIPTION

setsid creates a new session. The calling process is its session leader. The calling process is the process group leader of the new process group; it must not already be a process group leader. The calling process does not have a controlling terminal. The calling process begins as the only process in the new process group and in the new session. The process group ID of the new process group is equal to the process ID of the caller.

RETURN VALUE

setsid returns the value of the new process group ID of the calling process. setsid returns a -1 if not successful.

EXAMPLE

The following code fragment illustrates the use of setsid to create a new session:

 #include <sys/types.h>
 #include <unistd.h>
 #include <stdio.h>

 pid_t pid;

 .
 .
 .
 printf("The process group ID is %d\n", (int) getpgrp());

 if ((pid = setsid()) == -1)
    perror("setsid error");
 else
    printf("The new process group ID is %d\n", (int) pid);
 .
 .
 .

Note: Also see the setpgid example.

RELATED FUNCTIONS

setpgid